The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
The hollow, muscular organ that maintains the circulation of the blood.
The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.
A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.
The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
Pathological conditions involving the HEART including its structural and functional abnormalities.
The transference of a heart from one human or animal to another.
Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
Method in which prolonged electrocardiographic recordings are made on a portable tape recorder (Holter-type system) or solid-state device ("real-time" system), while the patient undergoes normal daily activities. It is useful in the diagnosis and management of intermittent cardiac arrhythmias and transient myocardial ischemia.
A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.
The chambers of the heart, to which the BLOOD returns from the circulation.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.
Flaps of tissue that prevent regurgitation of BLOOD from the HEART VENTRICLES to the HEART ATRIA or from the PULMONARY ARTERIES or AORTA to the ventricles.
Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.
Contractile activity of the MYOCARDIUM.
Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
Elements of limited time intervals, contributing to particular results or situations.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Examinations used to diagnose and treat heart conditions.
The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.
Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.
The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.
The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).
A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (CORONARY ARTERY DISEASE), to obstruction by a thrombus (CORONARY THROMBOSIS), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (MYOCARDIAL INFARCTION).
The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.
Processes and properties of the CARDIOVASCULAR SYSTEM as a whole or of any of its parts.
Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.
An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.
Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.
The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Freedom from activity.
Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.
AMINO ALCOHOLS containing the propanolamine (NH2CH2CHOHCH2) group and its derivatives.
The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).
Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).
A procedure to stop the contraction of MYOCARDIUM during HEART SURGERY. It is usually achieved with the use of chemicals (CARDIOPLEGIC SOLUTIONS) or cold temperature (such as chilled perfusate).
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
Diseases of the parasympathetic or sympathetic divisions of the AUTONOMIC NERVOUS SYSTEM; which has components located in the CENTRAL NERVOUS SYSTEM and PERIPHERAL NERVOUS SYSTEM. Autonomic dysfunction may be associated with HYPOTHALAMIC DISEASES; BRAIN STEM disorders; SPINAL CORD DISEASES; and PERIPHERAL NERVOUS SYSTEM DISEASES. Manifestations include impairments of vegetative functions including the maintenance of BLOOD PRESSURE; HEART RATE; pupil function; SWEATING; REPRODUCTIVE AND URINARY PHYSIOLOGY; and DIGESTION.
NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
Irregular HEART RATE caused by abnormal function of the SINOATRIAL NODE. It is characterized by a greater than 10% change between the maximum and the minimum sinus cycle length or 120 milliseconds.
A state of subnormal or depressed cardiac output at rest or during stress. It is a characteristic of CARDIOVASCULAR DISEASES, including congenital, valvular, rheumatic, hypertensive, coronary, and cardiomyopathic. The serious form of low cardiac output is characterized by marked reduction in STROKE VOLUME, and systemic vasoconstriction resulting in cold, pale, and sometimes cyanotic extremities.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.
The position or attitude of the body.
A selective adrenergic beta-1 blocking agent that is commonly used to treat ANGINA PECTORIS; HYPERTENSION; and CARDIAC ARRHYTHMIAS.
Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
The posture of an individual lying face up.
Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Period of contraction of the HEART, especially of the HEART VENTRICLES.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.
A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
The measure of the level of heat of a human or animal.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.
A condition in which the LEFT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE; MYOCARDIAL INFARCTION; and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the left ventricular wall.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
The flow of BLOOD through or around an organ or region of the body.
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
A cardioselective beta-1 adrenergic blocker possessing properties and potency similar to PROPRANOLOL, but without a negative inotropic effect.
Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.
Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.
Physiologic or biochemical monitoring of the fetus. It is usually done during LABOR, OBSTETRIC and may be performed in conjunction with the monitoring of uterine activity. It may also be performed prenatally as when the mother is undergoing surgery.
A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.
Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.
Damage to the MYOCARDIUM resulting from MYOCARDIAL REPERFUSION (restoration of blood flow to ischemic areas of the HEART.) Reperfusion takes place when there is spontaneous thrombolysis, THROMBOLYTIC THERAPY, collateral flow from other coronary vascular beds, or reversal of vasospasm.
A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.
A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
Heart failure caused by abnormal myocardial contraction during SYSTOLE leading to defective cardiac emptying.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
Drugs that selectively bind to and activate beta-adrenergic receptors.
Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.
The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.
Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.
Sense of awareness of self and of the environment.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
The geometric and structural changes that the HEART VENTRICLES undergo, usually following MYOCARDIAL INFARCTION. It comprises expansion of the infarct and dilatation of the healthy ventricle segments. While most prevalent in the left ventricle, it can also occur in the right ventricle.
A pumping mechanism that duplicates the output, rate, and blood pressure of the natural heart. It may replace the function of the entire heart or a portion of it, and may be an intracorporeal, extracorporeal, or paracorporeal heart. (Dorland, 28th ed)
Treatment process involving the injection of fluid into an organ or tissue.
This structure includes the thin muscular atrial septum between the two HEART ATRIA, and the thick muscular ventricular septum between the two HEART VENTRICLES.
Forced expiratory effort against a closed GLOTTIS.
Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)
Compounds with BENZENE fused to AZEPINES.
An activity in which the organism plunges into water. It includes scuba and bell diving. Diving as natural behavior of animals goes here, as well as diving in decompression experiments with humans or animals.
Drugs used to cause dilation of the blood vessels.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
General or unspecified injuries to the heart.
The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.
Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; (especially DIURETICS, THIAZIDE); ADRENERGIC BETA-ANTAGONISTS; ADRENERGIC ALPHA-ANTAGONISTS; ANGIOTENSIN-CONVERTING ENZYME INHIBITORS; CALCIUM CHANNEL BLOCKERS; GANGLIONIC BLOCKERS; and VASODILATOR AGENTS.
Interruption of sympathetic pathways, by local injection of an anesthetic agent, at any of four levels: peripheral nerve block, sympathetic ganglion block, extradural block, and subarachnoid block.
Cardiac manifestation of systemic rheumatological conditions, such as RHEUMATIC FEVER. Rheumatic heart disease can involve any part the heart, most often the HEART VALVES and the ENDOCARDIUM.
Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.
A device that substitutes for a heart valve. It may be composed of biological material (BIOPROSTHESIS) and/or synthetic material.
Drugs that bind to and block the activation of ADRENERGIC BETA-1 RECEPTORS.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Unexpected rapid natural death due to cardiovascular collapse within one hour of initial symptoms. It is usually caused by the worsening of existing heart diseases. The sudden onset of symptoms, such as CHEST PAIN and CARDIAC ARRHYTHMIAS, particularly VENTRICULAR TACHYCARDIA, can lead to the loss of consciousness and cardiac arrest followed by biological death. (from Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005)
The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.
The time span between the beginning of physical activity by an individual and the termination because of exhaustion.
Relatively complete absence of oxygen in one or more tissues.
Monitoring of FETAL HEART frequency before birth in order to assess impending prematurity in relation to the pattern or intensity of antepartum UTERINE CONTRACTION.
One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.
Drugs that mimic the effects of stimulating postganglionic adrenergic sympathetic nerves. Included here are drugs that directly stimulate adrenergic receptors and drugs that act indirectly by provoking the release of adrenergic transmitters.
Drugs that inhibit the actions of the sympathetic nervous system by any mechanism. The most common of these are the ADRENERGIC ANTAGONISTS and drugs that deplete norepinephrine or reduce the release of transmitters from adrenergic postganglionic terminals (see ADRENERGIC AGENTS). Drugs that act in the central nervous system to reduce sympathetic activity (e.g., centrally acting alpha-2 adrenergic agonists, see ADRENERGIC ALPHA-AGONISTS) are included here.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.
Measurement of intracardiac blood flow using an M-mode and/or two-dimensional (2-D) echocardiogram while simultaneously recording the spectrum of the audible Doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells.
Heart failure caused by abnormal myocardial relaxation during DIASTOLE leading to defective cardiac filling.
A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).
The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.
A voluntary organization concerned with the prevention and treatment of heart and vascular diseases.
A strain of Rattus norvegicus with elevated blood pressure used as a model for studying hypertension and stroke.
A PEPTIDE that is secreted by the BRAIN and the HEART ATRIA, stored mainly in cardiac ventricular MYOCARDIUM. It can cause NATRIURESIS; DIURESIS; VASODILATION; and inhibits secretion of RENIN and ALDOSTERONE. It improves heart function. It contains 32 AMINO ACIDS.
A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.
The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.
Agents that inhibit the actions of the parasympathetic nervous system. The major group of drugs used therapeutically for this purpose is the MUSCARINIC ANTAGONISTS.
The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery.
A type of cardiac arrhythmia with premature contractions of the HEART VENTRICLES. It is characterized by the premature QRS complex on ECG that is of abnormal shape and great duration (generally >129 msec). It is the most common form of all cardiac arrhythmias. Premature ventricular complexes have no clinical significance except in concurrence with heart diseases.
The blood pressure in the ARTERIES. It is commonly measured with a SPHYGMOMANOMETER on the upper arm which represents the arterial pressure in the BRACHIAL ARTERY.
The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)
A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.
Injections made into a vein for therapeutic or experimental purposes.
The hemodynamic and electrophysiological action of the HEART ATRIA.
A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.
The circulation of blood through the CORONARY VESSELS of the HEART.
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
Diet modification and physical exercise to improve the ability of animals to perform physical activities.
The long-term (minutes to hours) administration of a fluid into the vein through venipuncture, either by letting the fluid flow by gravity or by pumping it.
Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
A cardiotonic glycoside obtained mainly from Digitalis lanata; it consists of three sugars and the aglycone DIGOXIGENIN. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in ATRIAL FIBRILLATION and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. (From Martindale, The Extra Pharmacopoeia, 30th ed, p666)
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Stress wherein emotional factors predominate.
A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.
A catecholamine derivative with specificity for BETA-1 ADRENERGIC RECEPTORS. It is commonly used as a cardiotonic agent after CARDIAC SURGERY and during DOBUTAMINE STRESS ECHOCARDIOGRAPHY.
The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.
An absence of warmth or heat or a temperature notably below an accustomed norm.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Enlargement of the LEFT VENTRICLE of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality.
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The unfavorable effect of environmental factors (stressors) on the physiological functions of an organism. Prolonged unresolved physiological stress can affect HOMEOSTASIS of the organism, and may lead to damaging or pathological conditions.
Part of the arm in humans and primates extending from the ELBOW to the WRIST.
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
An infant during the first month after birth.
The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.
Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.
The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)
A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
The ability to carry out daily tasks and perform physical activities in a highly functional state, often as a result of physical conditioning.
A significant drop in BLOOD PRESSURE after assuming a standing position. Orthostatic hypotension is a finding, and defined as a 20-mm Hg decrease in systolic pressure or a 10-mm Hg decrease in diastolic pressure 3 minutes after the person has risen from supine to standing. Symptoms generally include DIZZINESS, blurred vision, and SYNCOPE.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.
Agents having as their major action the interruption of neural transmission at nicotinic receptors on postganglionic autonomic neurons. Because their actions are so broad, including blocking of sympathetic and parasympathetic systems, their therapeutic use has been largely supplanted by more specific drugs. They may still be used in the control of blood pressure in patients with acute dissecting aortic aneurysm and for the induction of hypotension in surgery.
A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.
Abnormalities in any part of the HEART SEPTUM resulting in abnormal communication between the left and the right chambers of the heart. The abnormal blood flow inside the heart may be caused by defects in the ATRIAL SEPTUM, the VENTRICULAR SEPTUM, or both.
A condition caused by underdevelopment of the whole left half of the heart. It is characterized by hypoplasia of the left cardiac chambers (HEART ATRIUM; HEART VENTRICLE), the AORTA, the AORTIC VALVE, and the MITRAL VALVE. Severe symptoms appear in early infancy when DUCTUS ARTERIOSUS closes.
Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.
A beta-1 adrenergic antagonist that has been used in the emergency treatment of CARDIAC ARRYTHMIAS.
The oxygen consumption level above which aerobic energy production is supplemented by anaerobic mechanisms during exercise, resulting in a sustained increase in lactate concentration and metabolic acidosis. The anaerobic threshold is affected by factors that modify oxygen delivery to the tissues; it is low in patients with heart disease. Methods of measurement include direct measure of lactate concentration, direct measurement of bicarbonate concentration, and gas exchange measurements.
Tumors in any part of the heart. They include primary cardiac tumors and metastatic tumors to the heart. Their interference with normal cardiac functions can cause a wide variety of symptoms including HEART FAILURE; CARDIAC ARRHYTHMIAS; or EMBOLISM.
A change in electrical resistance of the skin, occurring in emotion and in certain other conditions.
A condition in which HEART VENTRICLES exhibit impaired function.
A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)
The vessels carrying blood away from the heart.
Benzo-indoles similar to CARBOLINES which are pyrido-indoles. In plants, carbazoles are derived from indole and form some of the INDOLE ALKALOIDS.
An activity in which the body is propelled by moving the legs rapidly. Running is performed at a moderate to rapid pace and should be differentiated from JOGGING, which is performed at a much slower pace.

Graphic monitoring of labour. (1/19128)

The parturograph is a composite record designed for the monitoring of fetal and maternal well-being and the progress of labour. It permits the early recognition of abnormalities and pinpoints the patients who would benefit most from intervention. Observations are made from the time of admission of the mother to the caseroom and recorded graphically. Factors assessed include fetal heart rate, maternal vital signs and urine, cervical dilatation, descent of the presenting fetal part, and frequency, duration and intensity of uterine contractions.  (+info)

Reduction in baroreflex cardiovascular responses due to venous infusion in the rabbit. (2/19128)

We studied reflex bradycardia and depression of mean arterial blood pressure (MAP) during left aortic nerve (LAN) stimulation before and after volume infusion in the anesthetized rabbit. Step increases in mean right atrial pressure (MRAP) to 10 mm Hg did not result in a significant change in heart rate or MAP. After volume loading, responses to LAN stimulation were not as great and the degree of attenuation was propoetional to the level of increased MRAP. A change in responsiveness was observed after elevation of MRAP by only 1 mm Hg, corresponding to less than a 10% increase in average calculated blood volume. after an increase in MRAP of 10 mm Hg, peak responses were attenuated by 44% (heart rate) and 52% (MAP), and the initial slopes (rate of change) were reduced by 46% (heart rate) and 66% (MAP). Comparison of the responses after infusion with blood and dextran solutions indicated that hemodilution was an unlikely explanation for the attenuation of the reflex responses. Total arterial baroreceptor denervation (ABD) abolished the volume-related attenuation was still present following bilateral aortic nerve section or vagotomy. It thus appears that the carotid sinus responds to changes inblood volume and influences the reflex cardiovascular responses to afferent stimulation of the LAN. On the other hand, cardiopulmonary receptors subserved by vagal afferents do not appear to be involved.  (+info)

Quantification of baroreceptor influence on arterial pressure changes seen in primary angiotension-induced hypertension in dogs. (3/19128)

We studied the role of the sino-aortic baroreceptors in the gradual development of hypertension induced by prolonged administration of small amounts of angiotensin II (A II) in intact dogs and dogs with denervated sino-aortic baroreceptors. Short-term 1-hour infusions of A II(1.0-100 ng/kg per min) showed that conscious denervated dogs had twice the pressor sensitivity of intact dogs. Long-term infusions of A II at 5.0 ng/kg per min (2-3 weeks) with continuous 24-hour recordings of arterial pressure showed that intact dogs required 28 hours to reach the same level of pressure attained by denervated dogs during the 1st hour of infusion. At the 28th hour the pressure in both groups was 70% of the maximum value attained by the 7th day of infusion. Both intact and denervated dogs reached nearly the same plateau level of pressure, the magnitude being directly related both the the A II infusion rate and the daily sodium intake. Cardiac output in intact dogs initially decreased after the onset of A II infusion, but by the 5th day of infusion it was 38% above control, whereas blood volume was unchanged. Heart rate returned to normal after a reduction during the 1st day of infusion in intact dogs. Plasma renin activity could not be detected after 24 hours of A II infusion in either intact or denervated dogs. The data indicate that about 35% of the hypertensive effect of A II results from its acute pressor action, and an additional 35% of the gradual increase in arterial pressure is in large measure a result of baroreceptor resetting. We conclude that the final 30% increase in pressure seems to result from increased cardiac output, the cause of which may be decreased vascular compliance. since the blood volume remains unaltered.  (+info)

Evaluation of the force-frequency relationship as a descriptor of the inotropic state of canine left ventricular myocardium. (4/19128)

The short-term force-frequency characteristics of canine left ventricular myocardium were examined in both isolated and intact preparations by briefly pertubing the frequency of contraction with early extrasystoles. The maximum rate of rise of isometric tension (Fmas) of the isolated trabeculae carneae was potentiated by the introduction of extrasystoles. The ratio of Fmas of potentiated to control beats (force-frequency ratio) was not altered significantly by a change in muscle length. However, exposure of the trabeculae to isoproterenol (10(-7)M) significantly changed the force-frequency ratio obtained in response to a constant frequency perturbation. Similar experiments were performed on chronically instrumented conscious dogs. Left ventricular minor axis diameter was measured with implanted pulse-transit ultrasonic dimension transducers, and intracavitary pressure was measured with a high fidelity micromanometer. Atrial pacing was performed so that the end-diastolic diameters of the beats preceding and following the extrasystole could be made identical. Large increases in the maximum rate of rise of pressure (Pmas) were seen in the contraction after the extrasystole. The ratio of Pmax of the potentiated beat to that of the control beat was not changed by a 9% increase in the end-diastolic diameter, produced by saline infusion. Conversely, isoproterenol significantly altered this relationship in the same manner as in the isolated muscle. Thus, either in vitro or in situ, left ventricular myocardium exhibits large functional changes in response to brief perturbations in rate. The isoproterenol and length data indicate that the force-frequency ratio reflects frequency-dependent changes in the inotropic state, independent of changes in length.  (+info)

Site of myocardial infarction. A determinant of the cardiovascular changes induced in the cat by coronary occlusion. (5/19128)

The influence of site of acute myocardial infarction on heart rate, blood pressure, cardiac output, total peripheral resistance (TPR), cardiac rhythm, and mortality was determined in 58 anesthetized cats by occlusion of either the left anterior descending (LAD), left circumflex or right coronary artery. LAD occlusion resulted in immediate decrease in cardiac output, heart rate, and blood pressure, an increase in TPR, and cardiac rhythm changes including premature ventricular beats, ventricular tachycardia, and occasionally ventricular fibrillation. The decrease in cardiac output and increase in TPR persisted in the cats surviving a ventricular arrhythmia. In contrast, right coronary occlusion resulted in a considerably smaller decrease in cardiac output. TPR did not increase, atrioventricular condition disturbances were common, and sinus bradycardia and hypotension persisted in the cats recovering from an arrhythmia. Left circumflex ligation resulted in cardiovascular changes intermediate between those produced by occlusion of the LAD or the right coronary artery. Mortality was similar in each of the three groups. We studied the coronary artery anatomy in 12 cats. In 10, the blood supply to the sinus node was from the right coronary artery and in 2, from the left circumflex coronary artery. The atrioventricular node artery arose from the right in 9 cats, and from the left circumflex in 3. The right coronary artery was dominant in 9 cats and the left in 3. In conclusion, the site of experimental coronary occlusion in cats is a major determinant of the hemodynamic and cardiac rhythm changes occurring after acute myocardial infarction. The cardiovascular responses evoked by ligation are related in part to the anatomical distribution of the occluded artery.  (+info)

Hierarchy of ventricular pacemakers. (6/19128)

To characterize the pattern of pacemaker dominance in the ventricular specialized conduction system (VSCS), escape ventricular pacemakers were localized and quantified in vivo and in virto, in normal hearts and in hearts 24 hours after myocardial infarction. Excape pacemaker foci were localized in vivo during vagally induced atrial arrest by means of electrograms recorded from the His bundle and proximal bundle branches and standard electrocardiographic limb leads. The VSCS was isolated using a modified Elizari preparation or preparations of each bundle branch. Peacemakers were located by extra- and intracellular recordings. Escape pacemaker foci in vivo were always in the proximal conduction system, usually the left bundle branch. The rate was 43+/-11 (mean+/-SD) beats/min. After beta-adrenergic blockade, the mean rate fell to 31+/-10 beats/min, but there were no shifts in pacemaker location. In the infarcted hearts, pacemakers were located in the peripheral left bundle branch. The mean rate was 146+/-20 beats/min. In isolated normal preparations, the dominant pacemakers usually were in the His bundle, firing at a mean rate of 43+/-10 beats/min. The rates of pacemakers diminished with distal progression. In infarcted hearts, the pacemakers invariably were in the infarct zone. The mean firing rates were not influenced by beta-adrenergic blockade. The results indicate that the dominant pacemakers are normally in the very proximal VSCS, but after myocardial infarction pacemaker dominance is shifted into the infarct. Distribution of pacemaker dominance is independent of sympathetic influence.  (+info)

Perioperative growth hormone treatment and functional outcome after major abdominal surgery: a randomized, double-blind, controlled study. (7/19128)

OBJECTIVE: To evaluate short- and long-term effects of perioperative human growth hormone (hGH) treatment on physical performance and fatigue in younger patients undergoing a major abdominal operation in a normal postoperative regimen with oral nutrition. SUMMARY BACKGROUND DATA: Muscle wasting and functional impairment follow major abdominal surgery. METHODS: Twenty-four patients with ulcerative colitis undergoing ileoanal J-pouch surgery were randomized to hGH (12 IU/day) or placebo treatment from 2 days before to 7 days after surgery. Measurements were performed 2 days before and 10, 30, and 90 days after surgery. RESULTS: The total muscle strength of four limb muscle groups was reduced by 7.6% in the hGH group and by 17.1% in the placebo group at postoperative day 10 compared with baseline values. There was also a significant difference between treatment groups in total muscle strength at day 30, and at the 90-day follow-up total muscle strength was equal to baseline values in the hGH group, but still significantly 5.9% below in the placebo group. The work capacity decreased by approximately 20% at day 10 after surgery, with no significant difference between treatment groups. Both groups were equally fatigued at day 10 after surgery, but at day 30 and 90 the hGH patients were less fatigued than the placebo patients. During the treatment period, patients receiving hGH had reduced loss of limb lean tissue mass, and 3 months after surgery the hGH patients had regained more lean tissue mass than placebo patients. CONCLUSIONS: Perioperative hGH treatment of younger patients undergoing major abdominal surgery preserved limb lean tissue mass, increased postoperative muscular strength, and reduced long-term postoperative fatigue.  (+info)

Heart rate and subsequent blood pressure in young adults: the CARDIA study. (8/19128)

The objective of the present study was to examine the hypothesis that baseline heart rate (HR) predicts subsequent blood pressure (BP) independently of baseline BP. In the multicenter longitudinal Coronary Artery Risk Development in Young Adults study of black and white men and women initially aged 18 to 30 years, we studied 4762 participants who were not current users of antihypertensive drugs and had no history of heart problems at the baseline examination (1985-1986). In each race-sex subgroup, we estimated the effect of baseline HR on BP 2, 5, 7, and 10 years later by use of repeated measures regression analysis, adjusting for baseline BP, age, education, body fatness, physical fitness, fasting insulin, parental hypertension, cigarette smoking, alcohol consumption, oral contraceptive use, and change of body mass index from baseline. The association between baseline HR and subsequent systolic BP (SBP) was explained by multivariable adjustment. However, HR was an independent predictor of subsequent diastolic BP (DBP) regardless of initial BP and other confounders in white men, white women, and black men (0.7 mm Hg increase per 10 bpm). We incorporated the part of the association that was already present at baseline by not adjusting for baseline DBP: the mean increase in subsequent DBP was 1.3 mm Hg per 10 bpm in white men, white women, and black men. A high HR may be considered a risk factor for subsequent high DBP in young persons.  (+info)

Heart rate is the number of heartbeats per unit of time, often expressed as beats per minute (bpm). It can vary significantly depending on factors such as age, physical fitness, emotions, and overall health status. A resting heart rate between 60-100 bpm is generally considered normal for adults, but athletes and individuals with high levels of physical fitness may have a resting heart rate below 60 bpm due to their enhanced cardiovascular efficiency. Monitoring heart rate can provide valuable insights into an individual's health status, exercise intensity, and response to various treatments or interventions.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

Fetal heart rate (FHR) is the number of times a fetus's heart beats in one minute. It is measured through the use of a fetoscope, Doppler ultrasound device, or cardiotocograph (CTG). A normal FHR ranges from 120 to 160 beats per minute (bpm), although it can vary throughout pregnancy and is usually faster than an adult's heart rate. Changes in the FHR pattern may indicate fetal distress, hypoxia, or other conditions that require medical attention. Regular monitoring of FHR during pregnancy, labor, and delivery helps healthcare providers assess fetal well-being and ensure a safe outcome for both the mother and the baby.

Heart failure is a pathophysiological state in which the heart is unable to pump sufficient blood to meet the metabolic demands of the body or do so only at the expense of elevated filling pressures. It can be caused by various cardiac disorders, including coronary artery disease, hypertension, valvular heart disease, cardiomyopathy, and arrhythmias. Symptoms may include shortness of breath, fatigue, and fluid retention. Heart failure is often classified based on the ejection fraction (EF), which is the percentage of blood that is pumped out of the left ventricle during each contraction. A reduced EF (less than 40%) is indicative of heart failure with reduced ejection fraction (HFrEF), while a preserved EF (greater than or equal to 50%) is indicative of heart failure with preserved ejection fraction (HFpEF). There is also a category of heart failure with mid-range ejection fraction (HFmrEF) for those with an EF between 40-49%.

The Autonomic Nervous System (ANS) is a part of the peripheral nervous system that operates largely below the level of consciousness and controls visceral functions. It is divided into two main subdivisions: the sympathetic and parasympathetic nervous systems, which generally have opposing effects and maintain homeostasis in the body.

The Sympathetic Nervous System (SNS) prepares the body for stressful or emergency situations, often referred to as the "fight or flight" response. It increases heart rate, blood pressure, respiratory rate, and metabolic rate, while also decreasing digestive activity. This response helps the body respond quickly to perceived threats.

The Parasympathetic Nervous System (PNS), on the other hand, promotes the "rest and digest" state, allowing the body to conserve energy and restore itself after the stress response has subsided. It decreases heart rate, blood pressure, and respiratory rate, while increasing digestive activity and promoting relaxation.

These two systems work together to maintain balance in the body by adjusting various functions based on internal and external demands. Disorders of the Autonomic Nervous System can lead to a variety of symptoms, such as orthostatic hypotension, gastroparesis, and cardiac arrhythmias, among others.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

Heart disease is a broad term for a class of diseases that involve the heart or blood vessels. It's often used to refer to conditions that include:

1. Coronary artery disease (CAD): This is the most common type of heart disease. It occurs when the arteries that supply blood to the heart become hardened and narrowed due to the buildup of cholesterol and other substances, which can lead to chest pain (angina), shortness of breath, or a heart attack.

2. Heart failure: This condition occurs when the heart is unable to pump blood efficiently to meet the body's needs. It can be caused by various conditions, including coronary artery disease, high blood pressure, and cardiomyopathy.

3. Arrhythmias: These are abnormal heart rhythms, which can be too fast, too slow, or irregular. They can lead to symptoms such as palpitations, dizziness, and fainting.

4. Valvular heart disease: This involves damage to one or more of the heart's four valves, which control blood flow through the heart. Damage can be caused by various conditions, including infection, rheumatic fever, and aging.

5. Cardiomyopathy: This is a disease of the heart muscle that makes it harder for the heart to pump blood efficiently. It can be caused by various factors, including genetics, viral infections, and drug abuse.

6. Pericardial disease: This involves inflammation or other problems with the sac surrounding the heart (pericardium). It can cause chest pain and other symptoms.

7. Congenital heart defects: These are heart conditions that are present at birth, such as a hole in the heart or abnormal blood vessels. They can range from mild to severe and may require medical intervention.

8. Heart infections: The heart can become infected by bacteria, viruses, or parasites, leading to various symptoms and complications.

It's important to note that many factors can contribute to the development of heart disease, including genetics, lifestyle choices, and certain medical conditions. Regular check-ups and a healthy lifestyle can help reduce the risk of developing heart disease.

Heart transplantation is a surgical procedure where a diseased, damaged, or failing heart is removed and replaced with a healthy donor heart. This procedure is usually considered as a last resort for patients with end-stage heart failure or severe coronary artery disease who have not responded to other treatments. The donor heart typically comes from a brain-dead individual whose family has agreed to donate their loved one's organs for transplantation. Heart transplantation is a complex and highly specialized procedure that requires a multidisciplinary team of healthcare professionals, including cardiologists, cardiac surgeons, anesthesiologists, perfusionists, nurses, and other support staff. The success rates for heart transplantation have improved significantly over the past few decades, with many patients experiencing improved quality of life and increased survival rates. However, recipients of heart transplants require lifelong immunosuppressive therapy to prevent rejection of the donor heart, which can increase the risk of infections and other complications.

Congenital heart defects (CHDs) are structural abnormalities in the heart that are present at birth. They can affect any part of the heart's structure, including the walls of the heart, the valves inside the heart, and the major blood vessels that lead to and from the heart.

Congenital heart defects can range from mild to severe and can cause various symptoms depending on the type and severity of the defect. Some common symptoms of CHDs include cyanosis (a bluish tint to the skin, lips, and fingernails), shortness of breath, fatigue, poor feeding, and slow growth in infants and children.

There are many different types of congenital heart defects, including:

1. Septal defects: These are holes in the walls that separate the four chambers of the heart. The two most common septal defects are atrial septal defect (ASD) and ventricular septal defect (VSD).
2. Valve abnormalities: These include narrowed or leaky valves, which can affect blood flow through the heart.
3. Obstruction defects: These occur when blood flow is blocked or restricted due to narrowing or absence of a part of the heart's structure. Examples include pulmonary stenosis and coarctation of the aorta.
4. Cyanotic heart defects: These cause a lack of oxygen in the blood, leading to cyanosis. Examples include tetralogy of Fallot and transposition of the great arteries.

The causes of congenital heart defects are not fully understood, but genetic factors and environmental influences during pregnancy may play a role. Some CHDs can be detected before birth through prenatal testing, while others may not be diagnosed until after birth or later in childhood. Treatment for CHDs may include medication, surgery, or other interventions to improve blood flow and oxygenation of the body's tissues.

Hemodynamics is the study of how blood flows through the cardiovascular system, including the heart and the vascular network. It examines various factors that affect blood flow, such as blood volume, viscosity, vessel length and diameter, and pressure differences between different parts of the circulatory system. Hemodynamics also considers the impact of various physiological and pathological conditions on these variables, and how they in turn influence the function of vital organs and systems in the body. It is a critical area of study in fields such as cardiology, anesthesiology, and critical care medicine.

The fetal heart is the cardiovascular organ that develops in the growing fetus during pregnancy. It starts to form around 22 days after conception and continues to develop throughout the first trimester. By the end of the eighth week of gestation, the fetal heart has developed enough to pump blood throughout the body.

The fetal heart is similar in structure to the adult heart but has some differences. It is smaller and more compact, with a four-chambered structure that includes two atria and two ventricles. The fetal heart also has unique features such as the foramen ovale, which is a hole between the right and left atria that allows blood to bypass the lungs, and the ductus arteriosus, a blood vessel that connects the pulmonary artery to the aorta and diverts blood away from the lungs.

The fetal heart is responsible for pumping oxygenated blood from the placenta to the rest of the body and returning deoxygenated blood back to the placenta for re-oxygenation. The rate of the fetal heartbeat is faster than that of an adult, typically ranging from 120 to 160 beats per minute. Fetal heart rate monitoring is a common method used during pregnancy and childbirth to assess the health and well-being of the developing fetus.

The sympathetic nervous system (SNS) is a part of the autonomic nervous system that operates largely below the level of consciousness, and it functions to produce appropriate physiological responses to perceived danger. It's often associated with the "fight or flight" response. The SNS uses nerve impulses to stimulate target organs, causing them to speed up (e.g., increased heart rate), prepare for action, or otherwise respond to stressful situations.

The sympathetic nervous system is activated due to stressful emotional or physical situations and it prepares the body for immediate actions. It dilates the pupils, increases heart rate and blood pressure, accelerates breathing, and slows down digestion. The primary neurotransmitter involved in this system is norepinephrine (also known as noradrenaline).

Ambulatory electrocardiography, also known as ambulatory ECG or Holter monitoring, is a non-invasive method of recording the electrical activity of the heart over an extended period of time (typically 24 hours or more) while the patient goes about their daily activities. The device used to record the ECG is called a Holter monitor, which consists of a small, portable recorder that is attached to the patient's chest with electrodes.

The recorded data provides information on any abnormalities in the heart's rhythm or electrical activity during different stages of activity and rest, allowing healthcare providers to diagnose and evaluate various cardiac conditions such as arrhythmias, ischemia, and infarction. The ability to monitor the heart's activity over an extended period while the patient performs their normal activities provides valuable information that may not be captured during a standard ECG, which only records the heart's electrical activity for a few seconds.

In summary, ambulatory electrocardiography is a diagnostic tool used to evaluate the electrical activity of the heart over an extended period, allowing healthcare providers to diagnose and manage various cardiac conditions.

The baroreflex is a physiological mechanism that helps regulate blood pressure and heart rate in response to changes in stretch of the arterial walls. It is mediated by baroreceptors, which are specialized sensory nerve endings located in the carotid sinus and aortic arch. These receptors detect changes in blood pressure and send signals to the brainstem via the glossopharyngeal (cranial nerve IX) and vagus nerves (cranial nerve X), respectively.

In response to an increase in arterial pressure, the baroreceptors are stimulated, leading to increased firing of afferent neurons that signal the brainstem. This results in a reflexive decrease in heart rate and cardiac output, as well as vasodilation of peripheral blood vessels, which collectively work to reduce blood pressure back towards its normal level. Conversely, if arterial pressure decreases, the baroreceptors are less stimulated, leading to an increase in heart rate and cardiac output, as well as vasoconstriction of peripheral blood vessels, which helps restore blood pressure.

Overall, the baroreflex is a crucial homeostatic mechanism that helps maintain stable blood pressure and ensure adequate perfusion of vital organs.

The heart atria are the upper chambers of the heart that receive blood from the veins and deliver it to the lower chambers, or ventricles. There are two atria in the heart: the right atrium receives oxygen-poor blood from the body and pumps it into the right ventricle, which then sends it to the lungs to be oxygenated; and the left atrium receives oxygen-rich blood from the lungs and pumps it into the left ventricle, which then sends it out to the rest of the body. The atria contract before the ventricles during each heartbeat, helping to fill the ventricles with blood and prepare them for contraction.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

Adrenergic beta-antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-adrenergic receptors. These receptors are found in various tissues throughout the body, including the heart, lungs, and blood vessels.

Beta blockers work by binding to these receptors and preventing the activation of certain signaling pathways that lead to increased heart rate, force of heart contractions, and relaxation of blood vessels. As a result, beta blockers can lower blood pressure, reduce heart rate, and decrease the workload on the heart.

Beta blockers are used to treat a variety of medical conditions, including hypertension (high blood pressure), angina (chest pain), heart failure, irregular heart rhythms, migraines, and certain anxiety disorders. Some common examples of beta blockers include metoprolol, atenolol, propranolol, and bisoprolol.

It is important to note that while beta blockers can have many benefits, they can also cause side effects such as fatigue, dizziness, and shortness of breath. Additionally, sudden discontinuation of beta blocker therapy can lead to rebound hypertension or worsening chest pain. Therefore, it is important to follow the dosing instructions provided by a healthcare provider carefully when taking these medications.

Heart valves are specialized structures in the heart that ensure unidirectional flow of blood through its chambers during the cardiac cycle. There are four heart valves: the tricuspid valve and the mitral (bicuspid) valve, located between the atria and ventricles, and the pulmonic (pulmonary) valve and aortic valve, located between the ventricles and the major blood vessels leaving the heart.

The heart valves are composed of thin flaps of tissue called leaflets or cusps, which are supported by a fibrous ring. The aortic and pulmonic valves have three cusps each, while the tricuspid and mitral valves have three and two cusps, respectively.

The heart valves open and close in response to pressure differences across them, allowing blood to flow forward into the ventricles during diastole (filling phase) and preventing backflow of blood into the atria during systole (contraction phase). A properly functioning heart valve ensures efficient pumping of blood by the heart and maintains normal blood circulation throughout the body.

An exercise test, also known as a stress test or an exercise stress test, is a medical procedure used to evaluate the heart's function and response to physical exertion. It typically involves walking on a treadmill or pedaling a stationary bike while being monitored for changes in heart rate, blood pressure, electrocardiogram (ECG), and sometimes other variables such as oxygen consumption or gas exchange.

During the test, the patient's symptoms, such as chest pain or shortness of breath, are also closely monitored. The exercise test can help diagnose coronary artery disease, assess the severity of heart-related symptoms, and evaluate the effectiveness of treatments for heart conditions. It may also be used to determine a person's safe level of physical activity and fitness.

There are different types of exercise tests, including treadmill stress testing, stationary bike stress testing, nuclear stress testing, and stress echocardiography. The specific type of test used depends on the patient's medical history, symptoms, and overall health status.

Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.

During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.

Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.

Heart block is a cardiac condition characterized by the interruption of electrical impulse transmission from the atria (the upper chambers of the heart) to the ventricles (the lower chambers of the heart). This disruption can lead to abnormal heart rhythms, including bradycardia (a slower-than-normal heart rate), and in severe cases, can cause the heart to stop beating altogether. Heart block is typically caused by damage to the heart's electrical conduction system due to various factors such as aging, heart disease, or certain medications.

There are three types of heart block: first-degree, second-degree, and third-degree (also known as complete heart block). Each type has distinct electrocardiogram (ECG) findings and symptoms. Treatment for heart block depends on the severity of the condition and may include monitoring, medication, or implantation of a pacemaker to regulate the heart's electrical activity.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Oxygen consumption, also known as oxygen uptake, is the amount of oxygen that is consumed or utilized by the body during a specific period of time, usually measured in liters per minute (L/min). It is a common measurement used in exercise physiology and critical care medicine to assess an individual's aerobic metabolism and overall health status.

In clinical settings, oxygen consumption is often measured during cardiopulmonary exercise testing (CPET) to evaluate cardiovascular function, pulmonary function, and exercise capacity in patients with various medical conditions such as heart failure, chronic obstructive pulmonary disease (COPD), and other respiratory or cardiac disorders.

During exercise, oxygen is consumed by the muscles to generate energy through a process called oxidative phosphorylation. The amount of oxygen consumed during exercise can provide important information about an individual's fitness level, exercise capacity, and overall health status. Additionally, measuring oxygen consumption can help healthcare providers assess the effectiveness of treatments and rehabilitation programs in patients with various medical conditions.

Heart function tests are a group of diagnostic exams that are used to evaluate the structure and functioning of the heart. These tests help doctors assess the pumping efficiency of the heart, the flow of blood through the heart, the presence of any heart damage, and the overall effectiveness of the heart in delivering oxygenated blood to the rest of the body.

Some common heart function tests include:

1. Echocardiogram (Echo): This test uses sound waves to create detailed images of the heart's structure and functioning. It can help detect any damage to the heart muscle, valves, or sac surrounding the heart.
2. Nuclear Stress Test: This test involves injecting a small amount of radioactive substance into the patient's bloodstream and taking images of the heart while it is at rest and during exercise. The test helps evaluate blood flow to the heart and detect any areas of reduced blood flow, which could indicate coronary artery disease.
3. Cardiac Magnetic Resonance Imaging (MRI): This test uses magnetic fields and radio waves to create detailed images of the heart's structure and function. It can help detect any damage to the heart muscle, valves, or other structures of the heart.
4. Electrocardiogram (ECG): This test measures the electrical activity of the heart and helps detect any abnormalities in the heart's rhythm or conduction system.
5. Exercise Stress Test: This test involves walking on a treadmill or riding a stationary bike while being monitored for changes in heart rate, blood pressure, and ECG readings. It helps evaluate exercise capacity and detect any signs of coronary artery disease.
6. Cardiac Catheterization: This is an invasive procedure that involves inserting a catheter into the heart to measure pressures and take samples of blood from different parts of the heart. It can help diagnose various heart conditions, including heart valve problems, congenital heart defects, and coronary artery disease.

Overall, heart function tests play an essential role in diagnosing and managing various heart conditions, helping doctors provide appropriate treatment and improve patient outcomes.

The Parasympathetic Nervous System (PNS) is the part of the autonomic nervous system that primarily controls vegetative functions during rest, relaxation, and digestion. It is responsible for the body's "rest and digest" activities including decreasing heart rate, lowering blood pressure, increasing digestive activity, and stimulating sexual arousal. The PNS utilizes acetylcholine as its primary neurotransmitter and acts in opposition to the Sympathetic Nervous System (SNS), which is responsible for the "fight or flight" response.

Telemetry is the automated measurement and wireless transmission of data from remote or inaccessible sources to receiving stations for monitoring and analysis. In a medical context, telemetry is often used to monitor patients' vital signs such as heart rate, blood pressure, oxygen levels, and other important physiological parameters continuously and remotely. This technology allows healthcare providers to track patients' conditions over time, detect any abnormalities or trends, and make informed decisions about their care, even when they are not physically present with the patient. Telemetry is commonly used in hospitals, clinics, and research settings to monitor patients during procedures, after surgery, or during extended stays in intensive care units.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

Bradycardia is a medical term that refers to an abnormally slow heart rate, typically defined as a resting heart rate of less than 60 beats per minute in adults. While some people, particularly well-trained athletes, may have a naturally low resting heart rate, bradycardia can also be a sign of an underlying health problem.

There are several potential causes of bradycardia, including:

* Damage to the heart's electrical conduction system, such as from heart disease or aging
* Certain medications, including beta blockers, calcium channel blockers, and digoxin
* Hypothyroidism (underactive thyroid gland)
* Sleep apnea
* Infection of the heart (endocarditis or myocarditis)
* Infiltrative diseases such as amyloidosis or sarcoidosis

Symptoms of bradycardia can vary depending on the severity and underlying cause. Some people with bradycardia may not experience any symptoms, while others may feel weak, fatigued, dizzy, or short of breath. In severe cases, bradycardia can lead to fainting, confusion, or even cardiac arrest.

Treatment for bradycardia depends on the underlying cause. If a medication is causing the slow heart rate, adjusting the dosage or switching to a different medication may help. In other cases, a pacemaker may be necessary to regulate the heart's rhythm. It is important to seek medical attention if you experience symptoms of bradycardia, as it can be a sign of a serious underlying condition.

Propranolol is a medication that belongs to a class of drugs called beta blockers. Medically, it is defined as a non-selective beta blocker, which means it blocks the effects of both epinephrine (adrenaline) and norepinephrine (noradrenaline) on the heart and other organs. These effects include reducing heart rate, contractility, and conduction velocity, leading to decreased oxygen demand by the myocardium. Propranolol is used in the management of various conditions such as hypertension, angina pectoris, arrhythmias, essential tremor, anxiety disorders, and infants with congenital heart defects. It may also be used to prevent migraines and reduce the risk of future heart attacks. As with any medication, it should be taken under the supervision of a healthcare provider due to potential side effects and contraindications.

Stroke volume is a term used in cardiovascular physiology and medicine. It refers to the amount of blood that is pumped out of the left ventricle of the heart during each contraction (systole). Specifically, it is the difference between the volume of blood in the left ventricle at the end of diastole (when the ventricle is filled with blood) and the volume at the end of systole (when the ventricle has contracted and ejected its contents into the aorta).

Stroke volume is an important measure of heart function, as it reflects the ability of the heart to pump blood effectively to the rest of the body. A low stroke volume may indicate that the heart is not pumping efficiently, while a high stroke volume may suggest that the heart is working too hard. Stroke volume can be affected by various factors, including heart disease, high blood pressure, and physical fitness level.

The formula for calculating stroke volume is:

Stroke Volume = End-Diastolic Volume - End-Systolic Volume

Where end-diastolic volume (EDV) is the volume of blood in the left ventricle at the end of diastole, and end-systolic volume (ESV) is the volume of blood in the left ventricle at the end of systole.

Medical Definition of Respiration:

Respiration, in physiology, is the process by which an organism takes in oxygen and gives out carbon dioxide. It's also known as breathing. This process is essential for most forms of life because it provides the necessary oxygen for cellular respiration, where the cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and releases waste products, primarily carbon dioxide.

In humans and other mammals, respiration is a two-stage process:

1. Breathing (or external respiration): This involves the exchange of gases with the environment. Air enters the lungs through the mouth or nose, then passes through the pharynx, larynx, trachea, and bronchi, finally reaching the alveoli where the actual gas exchange occurs. Oxygen from the inhaled air diffuses into the blood, while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

2. Cellular respiration (or internal respiration): This is the process by which cells convert glucose and other nutrients into ATP, water, and carbon dioxide in the presence of oxygen. The carbon dioxide produced during this process then diffuses out of the cells and into the bloodstream to be exhaled during breathing.

In summary, respiration is a vital physiological function that enables organisms to obtain the necessary oxygen for cellular metabolism while eliminating waste products like carbon dioxide.

Myocardial ischemia is a condition in which the blood supply to the heart muscle (myocardium) is reduced or blocked, leading to insufficient oxygen delivery and potential damage to the heart tissue. This reduction in blood flow typically results from the buildup of fatty deposits, called plaques, in the coronary arteries that supply the heart with oxygen-rich blood. The plaques can rupture or become unstable, causing the formation of blood clots that obstruct the artery and limit blood flow.

Myocardial ischemia may manifest as chest pain (angina pectoris), shortness of breath, fatigue, or irregular heartbeats (arrhythmias). In severe cases, it can lead to myocardial infarction (heart attack) if the oxygen supply is significantly reduced or cut off completely, causing permanent damage or death of the heart muscle. Early diagnosis and treatment of myocardial ischemia are crucial for preventing further complications and improving patient outcomes.

Left ventricular function refers to the ability of the left ventricle (the heart's lower-left chamber) to contract and relax, thereby filling with and ejecting blood. The left ventricle is responsible for pumping oxygenated blood to the rest of the body. Its function is evaluated by measuring several parameters, including:

1. Ejection fraction (EF): This is the percentage of blood that is pumped out of the left ventricle with each heartbeat. A normal ejection fraction ranges from 55% to 70%.
2. Stroke volume (SV): The amount of blood pumped by the left ventricle in one contraction. A typical SV is about 70 mL/beat.
3. Cardiac output (CO): The total volume of blood that the left ventricle pumps per minute, calculated as the product of stroke volume and heart rate. Normal CO ranges from 4 to 8 L/minute.

Assessment of left ventricular function is crucial in diagnosing and monitoring various cardiovascular conditions such as heart failure, coronary artery disease, valvular heart diseases, and cardiomyopathies.

Cardiovascular physiological phenomena refer to the various functions and processes that occur within the cardiovascular system, which includes the heart and blood vessels. These phenomena are responsible for the transport of oxygen, nutrients, and other essential molecules to tissues throughout the body, as well as the removal of waste products and carbon dioxide.

Some examples of cardiovascular physiological phenomena include:

1. Heart rate and rhythm: The heart's ability to contract regularly and coordinate its contractions with the body's needs for oxygen and nutrients.
2. Blood pressure: The force exerted by blood on the walls of blood vessels, which is determined by the amount of blood pumped by the heart and the resistance of the blood vessels.
3. Cardiac output: The volume of blood that the heart pumps in one minute, calculated as the product of stroke volume (the amount of blood pumped per beat) and heart rate.
4. Blood flow: The movement of blood through the circulatory system, which is influenced by factors such as blood pressure, vessel diameter, and blood viscosity.
5. Vasoconstriction and vasodilation: The narrowing or widening of blood vessels in response to various stimuli, such as hormones, neurotransmitters, and changes in temperature or oxygen levels.
6. Autoregulation: The ability of blood vessels to maintain a constant blood flow to tissues despite changes in perfusion pressure.
7. Blood clotting: The process by which the body forms a clot to stop bleeding after an injury, which involves the activation of platelets and the coagulation cascade.
8. Endothelial function: The ability of the endothelium (the lining of blood vessels) to regulate vascular tone, inflammation, and thrombosis.
9. Myocardial contractility: The strength of heart muscle contractions, which is influenced by factors such as calcium levels, neurotransmitters, and hormones.
10. Electrophysiology: The study of the electrical properties of the heart, including the conduction system that allows for the coordinated contraction of heart muscle.

Tachycardia is a medical term that refers to an abnormally rapid heart rate, often defined as a heart rate greater than 100 beats per minute in adults. It can occur in either the atria (upper chambers) or ventricles (lower chambers) of the heart. Different types of tachycardia include supraventricular tachycardia (SVT), atrial fibrillation, atrial flutter, and ventricular tachycardia.

Tachycardia can cause various symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, chest discomfort, or syncope (fainting). In some cases, tachycardia may not cause any symptoms and may only be detected during a routine physical examination or medical test.

The underlying causes of tachycardia can vary widely, including heart disease, electrolyte imbalances, medications, illicit drug use, alcohol abuse, smoking, stress, anxiety, and other medical conditions. In some cases, the cause may be unknown. Treatment for tachycardia depends on the underlying cause, type, severity, and duration of the arrhythmia.

Physical exertion is defined as the act of applying energy to physically demandable activities or tasks, which results in various body systems working together to produce movement and maintain homeostasis. It often leads to an increase in heart rate, respiratory rate, and body temperature, among other physiological responses. The level of physical exertion can vary based on the intensity, duration, and frequency of the activity.

It's important to note that engaging in regular physical exertion has numerous health benefits, such as improving cardiovascular fitness, strengthening muscles and bones, reducing stress, and preventing chronic diseases like obesity, diabetes, and heart disease. However, it is also crucial to balance physical exertion with adequate rest and recovery time to avoid overtraining or injury.

Coronary artery disease, often simply referred to as coronary disease, is a condition in which the blood vessels that supply oxygen-rich blood to the heart become narrowed or blocked due to the buildup of fatty deposits called plaques. This can lead to chest pain (angina), shortness of breath, or in severe cases, a heart attack.

The medical definition of coronary artery disease is:

A condition characterized by the accumulation of atheromatous plaques in the walls of the coronary arteries, leading to decreased blood flow and oxygen supply to the myocardium (heart muscle). This can result in symptoms such as angina pectoris, shortness of breath, or arrhythmias, and may ultimately lead to myocardial infarction (heart attack) or heart failure.

Risk factors for coronary artery disease include age, smoking, high blood pressure, high cholesterol, diabetes, obesity, physical inactivity, and a family history of the condition. Lifestyle changes such as quitting smoking, exercising regularly, eating a healthy diet, and managing stress can help reduce the risk of developing coronary artery disease. Medical treatments may include medications to control blood pressure, cholesterol levels, or irregular heart rhythms, as well as procedures such as angioplasty or bypass surgery to improve blood flow to the heart.

Exercise is defined in the medical context as a physical activity that is planned, structured, and repetitive, with the primary aim of improving or maintaining one or more components of physical fitness. Components of physical fitness include cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, and body composition. Exercise can be classified based on its intensity (light, moderate, or vigorous), duration (length of time), and frequency (number of times per week). Common types of exercise include aerobic exercises, such as walking, jogging, cycling, and swimming; resistance exercises, such as weightlifting; flexibility exercises, such as stretching; and balance exercises. Exercise has numerous health benefits, including reducing the risk of chronic diseases, improving mental health, and enhancing overall quality of life.

The cardiovascular system, also known as the circulatory system, is a biological system responsible for pumping and transporting blood throughout the body in animals and humans. It consists of the heart, blood vessels (comprising arteries, veins, and capillaries), and blood. The main function of this system is to transport oxygen, nutrients, hormones, and cellular waste products throughout the body to maintain homeostasis and support organ function.

The heart acts as a muscular pump that contracts and relaxes to circulate blood. It has four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body, pumps it through the lungs for oxygenation, and then sends it back to the left side of the heart. The left side of the heart then pumps the oxygenated blood through the aorta and into the systemic circulation, reaching all parts of the body via a network of arteries and capillaries. Deoxygenated blood is collected by veins and returned to the right atrium, completing the cycle.

The cardiovascular system plays a crucial role in regulating temperature, pH balance, and fluid balance throughout the body. It also contributes to the immune response and wound healing processes. Dysfunctions or diseases of the cardiovascular system can lead to severe health complications, such as hypertension, coronary artery disease, heart failure, stroke, and peripheral artery disease.

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Medical Definition of Rest:

1. A state of motionless, inactivity, or repose of the body.
2. A period during which such a state is experienced, usually as a result of sleep or relaxation.
3. The cessation of mental or physical activity; a pause or interval of rest is a period of time in which one does not engage in work or exertion.
4. In medical contexts, rest may also refer to the treatment or management strategy that involves limiting physical activity or exertion in order to allow an injury or illness to heal, reduce pain or prevent further harm. This can include bed rest, where a person is advised to stay in bed for a certain period of time.
5. In physiology, rest refers to the state of the body when it is not engaged in physical activity and the muscles are at their resting length and tension. During rest, the body's systems have an opportunity to recover from the demands placed on them during activity, allowing for optimal functioning and overall health.

Pressoreceptors are specialized sensory nerve endings found in the walls of blood vessels, particularly in the carotid sinus and aortic arch. They respond to changes in blood pressure by converting the mechanical stimulus into electrical signals that are transmitted to the brain. This information helps regulate cardiovascular function and maintain blood pressure homeostasis.

Propanolamines are a class of pharmaceutical compounds that contain a propan-2-olamine functional group, which is a secondary amine formed by the replacement of one hydrogen atom in an ammonia molecule with a propan-2-ol group. They are commonly used as decongestants and bronchodilators in medical treatments.

Examples of propanolamines include:

* Phenylephrine: a decongestant used to relieve nasal congestion.
* Pseudoephedrine: a decongestant and stimulant used to treat nasal congestion and sinus pressure.
* Ephedrine: a bronchodilator, decongestant, and stimulant used to treat asthma, nasal congestion, and low blood pressure.

It is important to note that propanolamines can have side effects such as increased heart rate, elevated blood pressure, and insomnia, so they should be used with caution and under the supervision of a healthcare professional.

Cardiac output is a measure of the amount of blood that is pumped by the heart in one minute. It is defined as the product of stroke volume (the amount of blood pumped by the left ventricle during each contraction) and heart rate (the number of contractions per minute). Normal cardiac output at rest for an average-sized adult is about 5 to 6 liters per minute. Cardiac output can be increased during exercise or other conditions that require more blood flow, such as during illness or injury. It can be measured noninvasively using techniques such as echocardiography or invasively through a catheter placed in the heart.

Cardiotonic agents are a type of medication that have a positive inotropic effect on the heart, meaning they help to improve the contractility and strength of heart muscle contractions. These medications are often used to treat heart failure, as they can help to improve the efficiency of the heart's pumping ability and increase cardiac output.

Cardiotonic agents work by increasing the levels of calcium ions inside heart muscle cells during each heartbeat, which in turn enhances the force of contraction. Some common examples of cardiotonic agents include digitalis glycosides (such as digoxin), which are derived from the foxglove plant, and synthetic medications such as dobutamine and milrinone.

While cardiotonic agents can be effective in improving heart function, they can also have potentially serious side effects, including arrhythmias, electrolyte imbalances, and digestive symptoms. As a result, they are typically used under close medical supervision and their dosages may need to be carefully monitored to minimize the risk of adverse effects.

Induced heart arrest, also known as controlled cardiac arrest or planned cardiac arrest, is a deliberate medical intervention where cardiac activity is temporarily stopped through the use of medications or electrical disruption. This procedure is typically carried out during a surgical procedure, such as open-heart surgery, where the heart needs to be stilled to allow surgeons to work on it safely.

The most common method used to induce heart arrest is by administering a medication called potassium chloride, which stops the heart's electrical activity. Alternatively, an electrical shock may be delivered to the heart to achieve the same effect. Once the procedure is complete, the heart can be restarted using various resuscitation techniques, such as defibrillation or medication administration.

It's important to note that induced heart arrest is a carefully monitored and controlled medical procedure carried out by trained healthcare professionals in a hospital setting. It should not be confused with sudden cardiac arrest, which is an unexpected and often unpredictable event that occurs outside of a medical setting.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

The sinoatrial (SA) node, also known as the sinus node, is the primary pacemaker of the heart. It is a small bundle of specialized cardiac conduction tissue located in the upper part of the right atrium, near the entrance of the superior vena cava. The SA node generates electrical impulses that initiate each heartbeat, causing the atria to contract and pump blood into the ventricles. This process is called sinus rhythm.

The SA node's electrical activity is regulated by the autonomic nervous system, which can adjust the heart rate in response to changes in the body's needs, such as during exercise or rest. The SA node's rate of firing determines the heart rate, with a normal resting heart rate ranging from 60 to 100 beats per minute.

If the SA node fails to function properly or its electrical impulses are blocked, other secondary pacemakers in the heart may take over, resulting in abnormal heart rhythms called arrhythmias.

Echocardiography is a medical procedure that uses sound waves to produce detailed images of the heart's structure, function, and motion. It is a non-invasive test that can help diagnose various heart conditions, such as valve problems, heart muscle damage, blood clots, and congenital heart defects.

During an echocardiogram, a transducer (a device that sends and receives sound waves) is placed on the chest or passed through the esophagus to obtain images of the heart. The sound waves produced by the transducer bounce off the heart structures and return to the transducer, which then converts them into electrical signals that are processed to create images of the heart.

There are several types of echocardiograms, including:

* Transthoracic echocardiography (TTE): This is the most common type of echocardiogram and involves placing the transducer on the chest.
* Transesophageal echocardiography (TEE): This type of echocardiogram involves passing a specialized transducer through the esophagus to obtain images of the heart from a closer proximity.
* Stress echocardiography: This type of echocardiogram is performed during exercise or medication-induced stress to assess how the heart functions under stress.
* Doppler echocardiography: This type of echocardiogram uses sound waves to measure blood flow and velocity in the heart and blood vessels.

Echocardiography is a valuable tool for diagnosing and managing various heart conditions, as it provides detailed information about the structure and function of the heart. It is generally safe, non-invasive, and painless, making it a popular choice for doctors and patients alike.

A reflex is an automatic, involuntary and rapid response to a stimulus that occurs without conscious intention. In the context of physiology and neurology, it's a basic mechanism that involves the transmission of nerve impulses between neurons, resulting in a muscle contraction or glandular secretion.

Reflexes are important for maintaining homeostasis, protecting the body from harm, and coordinating movements. They can be tested clinically to assess the integrity of the nervous system, such as the knee-j jerk reflex, which tests the function of the L3-L4 spinal nerve roots and the sensitivity of the stretch reflex arc.

The Autonomic Nervous System (ANS) is a part of the nervous system that controls involuntary actions, such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. It consists of two subdivisions: the sympathetic and parasympathetic nervous systems, which generally have opposing effects and maintain homeostasis in the body.

Autonomic Nervous System Diseases (also known as Autonomic Disorders or Autonomic Neuropathies) refer to a group of conditions that affect the functioning of the autonomic nervous system. These diseases can cause damage to the nerves that control automatic functions, leading to various symptoms and complications.

Autonomic Nervous System Diseases can be classified into two main categories:

1. Primary Autonomic Nervous System Disorders: These are conditions that primarily affect the autonomic nervous system without any underlying cause. Examples include:
* Pure Autonomic Failure (PAF): A rare disorder characterized by progressive loss of autonomic nerve function, leading to symptoms such as orthostatic hypotension, urinary retention, and constipation.
* Multiple System Atrophy (MSA): A degenerative neurological disorder that affects both the autonomic nervous system and movement coordination. Symptoms may include orthostatic hypotension, urinary incontinence, sexual dysfunction, and Parkinsonian features like stiffness and slowness of movements.
* Autonomic Neuropathy associated with Parkinson's Disease: Some individuals with Parkinson's disease develop autonomic symptoms such as orthostatic hypotension, constipation, and urinary dysfunction due to the degeneration of autonomic nerves.
2. Secondary Autonomic Nervous System Disorders: These are conditions that affect the autonomic nervous system as a result of an underlying cause or disease. Examples include:
* Diabetic Autonomic Neuropathy: A complication of diabetes mellitus that affects the autonomic nerves, leading to symptoms such as orthostatic hypotension, gastroparesis (delayed gastric emptying), and sexual dysfunction.
* Autoimmune-mediated Autonomic Neuropathies: Conditions like Guillain-Barré syndrome or autoimmune autonomic ganglionopathy can cause autonomic symptoms due to the immune system attacking the autonomic nerves.
* Infectious Autonomic Neuropathies: Certain infections, such as HIV or Lyme disease, can lead to autonomic dysfunction as a result of nerve damage.
* Toxin-induced Autonomic Neuropathy: Exposure to certain toxins, like heavy metals or organophosphate pesticides, can cause autonomic neuropathy.

Autonomic nervous system disorders can significantly impact a person's quality of life and daily functioning. Proper diagnosis and management are crucial for improving symptoms and preventing complications. Treatment options may include lifestyle modifications, medications, and in some cases, devices or surgical interventions.

Myocardial infarction (MI), also known as a heart attack, is a medical condition characterized by the death of a segment of heart muscle (myocardium) due to the interruption of its blood supply. This interruption is most commonly caused by the blockage of a coronary artery by a blood clot formed on the top of an atherosclerotic plaque, which is a buildup of cholesterol and other substances in the inner lining of the artery.

The lack of oxygen and nutrients supply to the heart muscle tissue results in damage or death of the cardiac cells, causing the affected area to become necrotic. The extent and severity of the MI depend on the size of the affected area, the duration of the occlusion, and the presence of collateral circulation.

Symptoms of a myocardial infarction may include chest pain or discomfort, shortness of breath, nausea, lightheadedness, and sweating. Immediate medical attention is necessary to restore blood flow to the affected area and prevent further damage to the heart muscle. Treatment options for MI include medications, such as thrombolytics, antiplatelet agents, and pain relievers, as well as procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

Sinus arrhythmia is a type of heart rhythm disorder (arrhythmia) where the normal rhythm generated by the sinus node in the heart varies in rate or pattern. The sinus node is the natural pacemaker of the heart and usually sets a steady pace for heartbeats. However, in sinus arrhythmia, the heart rate may speed up or slow down abnormally during breathing in (inspiration) or breathing out (expiration).

When the heart rate increases during inspiration, it is called "inspiratory sinus arrhythmia," and when the heart rate decreases during expiration, it is called "expiratory sinus arrhythmia." Most people experience a mild form of inspiratory sinus arrhythmia, which is considered normal, especially in children and young adults.

However, if the variation in heart rate is significant or accompanied by symptoms such as palpitations, dizziness, shortness of breath, or chest discomfort, it may require medical evaluation and treatment. Sinus arrhythmia can be caused by various factors, including lung disease, heart disease, electrolyte imbalances, or the use of certain medications.

Cardiac output is a measure of the amount of blood that the heart pumps in one minute. It is calculated by multiplying the stroke volume (the amount of blood pumped by the left ventricle during each contraction) by the heart rate (the number of times the heart beats per minute). Low cardiac output refers to a condition in which the heart is not able to pump enough blood to meet the body's needs. This can occur due to various reasons such as heart failure, heart attack, or any other conditions that weaken the heart muscle. Symptoms of low cardiac output may include fatigue, shortness of breath, and decreased mental status. Treatment for low cardiac output depends on the underlying cause and may include medications, surgery, or medical devices to help support heart function.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Artificial cardiac pacing is a medical procedure that involves the use of an artificial device to regulate and stimulate the contraction of the heart muscle. This is often necessary when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart is beating too slowly or irregularly.

The artificial pacemaker consists of a small generator that produces electrical impulses and leads that are positioned in the heart to transmit the impulses. The generator is typically implanted just under the skin in the chest, while the leads are inserted into the heart through a vein.

There are different types of artificial cardiac pacing systems, including single-chamber pacemakers, which stimulate either the right atrium or right ventricle, and dual-chamber pacemakers, which stimulate both chambers of the heart. Some pacemakers also have additional features that allow them to respond to changes in the body's needs, such as during exercise or sleep.

Artificial cardiac pacing is a safe and effective treatment for many people with abnormal heart rhythms, and it can significantly improve their quality of life and longevity.

Posture is the position or alignment of body parts supported by the muscles, especially the spine and head in relation to the vertebral column. It can be described as static (related to a stationary position) or dynamic (related to movement). Good posture involves training your body to stand, walk, sit, and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities. Poor posture can lead to various health issues such as back pain, neck pain, headaches, and respiratory problems.

Metoprolol is a type of medication known as a beta blocker. According to the US National Library of Medicine's MedlinePlus, metoprolol is used to treat high blood pressure, angina (chest pain), and heart conditions that may occur after a heart attack. It works by blocking the action of certain natural chemicals in your body, such as epinephrine, on the heart and blood vessels. This helps to reduce the heart's workload, lower its blood pressure, and regulate its rhythm.

Metoprolol is available under various brand names, including Lopressor and Toprol-XL. It can be taken orally as a tablet or an extended-release capsule. As with any medication, metoprolol should be used under the supervision of a healthcare provider, who can monitor its effectiveness and potential side effects.

It is important to note that this definition is intended to provide a general overview of the medical use of metoprolol and should not be considered a substitute for professional medical advice.

Isoproterenol is a medication that belongs to a class of drugs called beta-adrenergic agonists. Medically, it is defined as a synthetic catecholamine with both alpha and beta adrenergic receptor stimulating properties. It is primarily used as a bronchodilator to treat conditions such as asthma and chronic obstructive pulmonary disease (COPD) by relaxing the smooth muscles in the airways, thereby improving breathing.

Isoproterenol can also be used in the treatment of bradycardia (abnormally slow heart rate), cardiac arrest, and heart blocks by increasing the heart rate and contractility. However, due to its non-selective beta-agonist activity, it may cause various side effects such as tremors, palpitations, and increased blood pressure. Its use is now limited due to the availability of more selective and safer medications.

Medical Definition:

"Risk factors" are any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury. They can be divided into modifiable and non-modifiable risk factors. Modifiable risk factors are those that can be changed through lifestyle choices or medical treatment, while non-modifiable risk factors are inherent traits such as age, gender, or genetic predisposition. Examples of modifiable risk factors include smoking, alcohol consumption, physical inactivity, and unhealthy diet, while non-modifiable risk factors include age, sex, and family history. It is important to note that having a risk factor does not guarantee that a person will develop the disease, but rather indicates an increased susceptibility.

The supine position is a term used in medicine to describe a body posture where an individual is lying down on their back, with their face and torso facing upwards. This position is often adopted during various medical procedures, examinations, or when resting, as it allows for easy access to the front of the body. It is also the position automatically assumed by most people who are falling asleep.

It's important to note that in the supine position, the head can be flat on the surface or raised with the use of pillows or specialized medical equipment like a hospital bed. This can help to alleviate potential issues such as breathing difficulties or swelling in the face and head.

Cardiovascular models are simplified representations or simulations of the human cardiovascular system used in medical research, education, and training. These models can be physical, computational, or mathematical and are designed to replicate various aspects of the heart, blood vessels, and blood flow. They can help researchers study the structure and function of the cardiovascular system, test new treatments and interventions, and train healthcare professionals in diagnostic and therapeutic techniques.

Physical cardiovascular models may include artificial hearts, blood vessels, or circulation systems made from materials such as plastic, rubber, or silicone. These models can be used to study the mechanics of heart valves, the effects of different surgical procedures, or the impact of various medical devices on blood flow.

Computational and mathematical cardiovascular models use algorithms and equations to simulate the behavior of the cardiovascular system. These models may range from simple representations of a single heart chamber to complex simulations of the entire circulatory system. They can be used to study the electrical activity of the heart, the biomechanics of blood flow, or the distribution of drugs in the body.

Overall, cardiovascular models play an essential role in advancing our understanding of the human body and improving patient care.

The double-blind method is a study design commonly used in research, including clinical trials, to minimize bias and ensure the objectivity of results. In this approach, both the participants and the researchers are unaware of which group the participants are assigned to, whether it be the experimental group or the control group. This means that neither the participants nor the researchers know who is receiving a particular treatment or placebo, thus reducing the potential for bias in the evaluation of outcomes. The assignment of participants to groups is typically done by a third party not involved in the study, and the codes are only revealed after all data have been collected and analyzed.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Systole is the phase of the cardiac cycle during which the heart muscle contracts to pump blood out of the heart. Specifically, it refers to the contraction of the ventricles, the lower chambers of the heart. This is driven by the action of the electrical conduction system of the heart, starting with the sinoatrial node and passing through the atrioventricular node and bundle branches to the Purkinje fibers.

During systole, the pressure within the ventricles increases as they contract, causing the aortic and pulmonary valves to open and allowing blood to be ejected into the systemic and pulmonary circulations, respectively. The duration of systole is typically shorter than that of diastole, the phase during which the heart muscle relaxes and the chambers fill with blood.

In clinical settings, the terms "systolic" and "diastolic" are often used to describe blood pressure measurements, with the former referring to the pressure exerted on the artery walls when the ventricles contract and eject blood, and the latter referring to the pressure when the ventricles are relaxed and filling with blood.

Computer-assisted signal processing is a medical term that refers to the use of computer algorithms and software to analyze, interpret, and extract meaningful information from biological signals. These signals can include physiological data such as electrocardiogram (ECG) waves, electromyography (EMG) signals, electroencephalography (EEG) readings, or medical images.

The goal of computer-assisted signal processing is to automate the analysis of these complex signals and extract relevant features that can be used for diagnostic, monitoring, or therapeutic purposes. This process typically involves several steps, including:

1. Signal acquisition: Collecting raw data from sensors or medical devices.
2. Preprocessing: Cleaning and filtering the data to remove noise and artifacts.
3. Feature extraction: Identifying and quantifying relevant features in the signal, such as peaks, troughs, or patterns.
4. Analysis: Applying statistical or machine learning algorithms to interpret the extracted features and make predictions about the underlying physiological state.
5. Visualization: Presenting the results in a clear and intuitive way for clinicians to review and use.

Computer-assisted signal processing has numerous applications in healthcare, including:

* Diagnosing and monitoring cardiac arrhythmias or other heart conditions using ECG signals.
* Assessing muscle activity and function using EMG signals.
* Monitoring brain activity and diagnosing neurological disorders using EEG readings.
* Analyzing medical images to detect abnormalities, such as tumors or fractures.

Overall, computer-assisted signal processing is a powerful tool for improving the accuracy and efficiency of medical diagnosis and monitoring, enabling clinicians to make more informed decisions about patient care.

Epinephrine, also known as adrenaline, is a hormone and a neurotransmitter that is produced in the body. It is released by the adrenal glands in response to stress or excitement, and it prepares the body for the "fight or flight" response. Epinephrine works by binding to specific receptors in the body, which causes a variety of physiological effects, including increased heart rate and blood pressure, improved muscle strength and alertness, and narrowing of the blood vessels in the skin and intestines. It is also used as a medication to treat various medical conditions, such as anaphylaxis (a severe allergic reaction), cardiac arrest, and low blood pressure.

Dilated cardiomyopathy (DCM) is a type of cardiomyopathy characterized by the enlargement and weakened contraction of the heart's main pumping chamber (the left ventricle). This enlargement and weakness can lead to symptoms such as shortness of breath, fatigue, and fluid retention. DCM can be caused by various factors including genetics, viral infections, alcohol and drug abuse, and other medical conditions like high blood pressure and diabetes. It is important to note that this condition can lead to heart failure if left untreated.

Body temperature is the measure of heat produced by the body. In humans, the normal body temperature range is typically between 97.8°F (36.5°C) and 99°F (37.2°C), with an average oral temperature of 98.6°F (37°C). Body temperature can be measured in various ways, including orally, rectally, axillary (under the arm), and temporally (on the forehead).

Maintaining a stable body temperature is crucial for proper bodily functions, as enzymes and other biological processes depend on specific temperature ranges. The hypothalamus region of the brain regulates body temperature through feedback mechanisms that involve shivering to produce heat and sweating to release heat. Fever is a common medical sign characterized by an elevated body temperature above the normal range, often as a response to infection or inflammation.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Diastole is the phase of the cardiac cycle during which the heart muscle relaxes and the chambers of the heart fill with blood. It follows systole, the phase in which the heart muscle contracts and pumps blood out to the body. In a normal resting adult, diastole lasts for approximately 0.4-0.5 seconds during each heartbeat. The period of diastole is divided into two phases: early diastole and late diastole. During early diastole, the ventricles fill with blood due to the pressure difference between the atria and ventricles. During late diastole, the atrioventricular valves close, and the ventricles continue to fill with blood due to the relaxation of the ventricular muscle and the compliance of the ventricular walls. The duration and pressure changes during diastole are important for maintaining adequate cardiac output and blood flow to the body.

Left ventricular dysfunction (LVD) is a condition characterized by the impaired ability of the left ventricle of the heart to pump blood efficiently during contraction. The left ventricle is one of the four chambers of the heart and is responsible for pumping oxygenated blood to the rest of the body.

LVD can be caused by various underlying conditions, such as coronary artery disease, cardiomyopathy, valvular heart disease, or hypertension. These conditions can lead to structural changes in the left ventricle, including remodeling, hypertrophy, and dilation, which ultimately impair its contractile function.

The severity of LVD is often assessed by measuring the ejection fraction (EF), which is the percentage of blood that is pumped out of the left ventricle during each contraction. A normal EF ranges from 55% to 70%, while an EF below 40% is indicative of LVD.

LVD can lead to various symptoms, such as shortness of breath, fatigue, fluid retention, and decreased exercise tolerance. It can also increase the risk of complications, such as heart failure, arrhythmias, and cardiac arrest. Treatment for LVD typically involves managing the underlying cause, along with medications to improve contractility, reduce fluid buildup, and control heart rate. In severe cases, devices such as implantable cardioverter-defibrillators (ICDs) or left ventricular assist devices (LVADs) may be required.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

Regional blood flow (RBF) refers to the rate at which blood flows through a specific region or organ in the body, typically expressed in milliliters per minute per 100 grams of tissue (ml/min/100g). It is an essential physiological parameter that reflects the delivery of oxygen and nutrients to tissues while removing waste products. RBF can be affected by various factors such as metabolic demands, neural regulation, hormonal influences, and changes in blood pressure or vascular resistance. Measuring RBF is crucial for understanding organ function, diagnosing diseases, and evaluating the effectiveness of treatments.

Cardiac arrhythmias are abnormal heart rhythms that result from disturbances in the electrical conduction system of the heart. The heart's normal rhythm is controlled by an electrical signal that originates in the sinoatrial (SA) node, located in the right atrium. This signal travels through the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood throughout the body.

An arrhythmia occurs when there is a disruption in this electrical pathway or when the heart's natural pacemaker produces an abnormal rhythm. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or irregularly.

There are several types of cardiac arrhythmias, including:

1. Atrial fibrillation: A rapid and irregular heartbeat that starts in the atria (the upper chambers of the heart).
2. Atrial flutter: A rapid but regular heartbeat that starts in the atria.
3. Supraventricular tachycardia (SVT): A rapid heartbeat that starts above the ventricles, usually in the atria or AV node.
4. Ventricular tachycardia: A rapid and potentially life-threatening heart rhythm that originates in the ventricles.
5. Ventricular fibrillation: A chaotic and disorganized electrical activity in the ventricles, which can be fatal if not treated immediately.
6. Heart block: A delay or interruption in the conduction of electrical signals from the atria to the ventricles.

Cardiac arrhythmias can cause various symptoms, such as palpitations, dizziness, shortness of breath, chest pain, and fatigue. In some cases, they may not cause any symptoms and go unnoticed. However, if left untreated, certain types of arrhythmias can lead to serious complications, including stroke, heart failure, or even sudden cardiac death.

Treatment for cardiac arrhythmias depends on the type, severity, and underlying causes. Options may include lifestyle changes, medications, cardioversion (electrical shock therapy), catheter ablation, implantable devices such as pacemakers or defibrillators, and surgery. It is essential to consult a healthcare professional for proper evaluation and management of cardiac arrhythmias.

A circadian rhythm is a roughly 24-hour biological cycle that regulates various physiological and behavioral processes in living organisms. It is driven by the body's internal clock, which is primarily located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain.

The circadian rhythm controls many aspects of human physiology, including sleep-wake cycles, hormone secretion, body temperature, and metabolism. It helps to synchronize these processes with the external environment, particularly the day-night cycle caused by the rotation of the Earth.

Disruptions to the circadian rhythm can have negative effects on health, leading to conditions such as insomnia, sleep disorders, depression, bipolar disorder, and even increased risk of chronic diseases like cancer, diabetes, and cardiovascular disease. Factors that can disrupt the circadian rhythm include shift work, jet lag, irregular sleep schedules, and exposure to artificial light at night.

A tilt-table test is a diagnostic procedure used to evaluate symptoms of syncope (fainting) or near-syncope. It measures your body's cardiovascular response to changes in position. During the test, you lie on a table that can be tilted to change the angle of your body from horizontal to upright. This simulates what happens when you stand up from a lying down position.

The test monitors heart rate, blood pressure, and oxygen levels while you're in different positions. If you experience symptoms like dizziness or fainting during the test, these can provide clues about the cause of your symptoms. The test is used to diagnose conditions like orthostatic hypotension (a sudden drop in blood pressure when standing), vasovagal syncope (fainting due to an overactive vagus nerve), and other heart rhythm disorders.

Atenolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and certain types of heart rhythm disorders. It works by blocking the action of certain hormones in the body, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart's workload, lower its rate and force of contractions, and improve blood flow.

Beta-blockers like atenolol are also sometimes used to prevent migraines or to treat symptoms of anxiety, such as rapid heartbeat or tremors. Atenolol is available in immediate-release and extended-release forms, and it is typically taken orally once or twice a day. As with any medication, atenolol can have side effects, including dizziness, fatigue, and gastrointestinal symptoms, and it may interact with other medications or medical conditions. It is important to use atenolol only under the supervision of a healthcare provider.

Hypotension is a medical term that refers to abnormally low blood pressure, usually defined as a systolic blood pressure less than 90 millimeters of mercury (mm Hg) or a diastolic blood pressure less than 60 mm Hg. Blood pressure is the force exerted by the blood against the walls of the blood vessels as the heart pumps blood.

Hypotension can cause symptoms such as dizziness, lightheadedness, weakness, and fainting, especially when standing up suddenly. In severe cases, hypotension can lead to shock, which is a life-threatening condition characterized by multiple organ failure due to inadequate blood flow.

Hypotension can be caused by various factors, including certain medications, medical conditions such as heart disease, endocrine disorders, and dehydration. It is important to seek medical attention if you experience symptoms of hypotension, as it can indicate an underlying health issue that requires treatment.

Cardiomegaly is a medical term that refers to an enlarged heart. It can be caused by various conditions such as high blood pressure, heart valve problems, cardiomyopathy, or fluid accumulation around the heart (pericardial effusion). Cardiomegaly can be detected through imaging tests like chest X-rays or echocardiograms. Depending on the underlying cause, treatment options may include medications, lifestyle changes, or in some cases, surgery. It is important to consult with a healthcare professional for proper diagnosis and treatment.

Fetal monitoring is a procedure used during labor and delivery to assess the well-being of the fetus. It involves the use of electronic devices to measure and record the fetal heart rate and uterine contractions. The information obtained from fetal monitoring can help healthcare providers identify any signs of fetal distress, such as a decreased fetal heart rate, which may indicate the need for interventions or an emergency cesarean delivery.

There are two main types of fetal monitoring: external and internal. External fetal monitoring involves placing sensors on the mother's abdomen to detect the fetal heart rate and uterine contractions. Internal fetal monitoring, which is typically used during high-risk deliveries, involves inserting an electrode into the fetus' scalp to measure the fetal heart rate more accurately.

Fetal monitoring can provide valuable information about the fetus's well-being during labor and delivery, but it is important to note that it has limitations and may not always detect fetal distress in a timely manner. Therefore, healthcare providers must use their clinical judgment and other assessment tools, such as fetal movement counting and visual examination of the fetus, to ensure the safe delivery of the baby.

Catecholamines are a group of hormones and neurotransmitters that are derived from the amino acid tyrosine. The most well-known catecholamines are dopamine, norepinephrine (also known as noradrenaline), and epinephrine (also known as adrenaline). These hormones are produced by the adrenal glands and are released into the bloodstream in response to stress. They play important roles in the "fight or flight" response, increasing heart rate, blood pressure, and alertness. In addition to their role as hormones, catecholamines also function as neurotransmitters, transmitting signals in the nervous system. Disorders of catecholamine regulation can lead to a variety of medical conditions, including hypertension, mood disorders, and neurological disorders.

Anti-arrhythmia agents are a class of medications used to treat abnormal heart rhythms or arrhythmias. These drugs work by modifying the electrical activity of the heart to restore and maintain a normal heart rhythm. There are several types of anti-arrhythmia agents, including:

1. Sodium channel blockers: These drugs slow down the conduction of electrical signals in the heart, which helps to reduce rapid or irregular heartbeats. Examples include flecainide, propafenone, and quinidine.
2. Beta-blockers: These medications work by blocking the effects of adrenaline on the heart, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include metoprolol, atenolol, and esmolol.
3. Calcium channel blockers: These drugs block the entry of calcium into heart muscle cells, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include verapamil and diltiazem.
4. Potassium channel blockers: These medications work by prolonging the duration of the heart's electrical cycle, which helps to prevent abnormal rhythms. Examples include amiodarone and sotalol.
5. Digoxin: This drug increases the force of heart contractions and slows down the heart rate, which can help to restore a normal rhythm in certain types of arrhythmias.

It's important to note that anti-arrhythmia agents can have significant side effects and should only be prescribed by a healthcare professional who has experience in managing arrhythmias. Close monitoring is necessary to ensure the medication is working effectively and not causing any adverse effects.

Follow-up studies are a type of longitudinal research that involve repeated observations or measurements of the same variables over a period of time, in order to understand their long-term effects or outcomes. In medical context, follow-up studies are often used to evaluate the safety and efficacy of medical treatments, interventions, or procedures.

In a typical follow-up study, a group of individuals (called a cohort) who have received a particular treatment or intervention are identified and then followed over time through periodic assessments or data collection. The data collected may include information on clinical outcomes, adverse events, changes in symptoms or functional status, and other relevant measures.

The results of follow-up studies can provide important insights into the long-term benefits and risks of medical interventions, as well as help to identify factors that may influence treatment effectiveness or patient outcomes. However, it is important to note that follow-up studies can be subject to various biases and limitations, such as loss to follow-up, recall bias, and changes in clinical practice over time, which must be carefully considered when interpreting the results.

Phenylephrine is a medication that belongs to the class of drugs known as sympathomimetic amines. It primarily acts as an alpha-1 adrenergic receptor agonist, which means it stimulates these receptors, leading to vasoconstriction (constriction of blood vessels). This effect can be useful in various medical situations, such as:

1. Nasal decongestion: When applied topically in the nose, phenylephrine causes constriction of the blood vessels in the nasal passages, which helps to relieve congestion and swelling. It is often found in over-the-counter (OTC) cold and allergy products.
2. Ocular circulation: In ophthalmology, phenylephrine is used to dilate the pupils before eye examinations. The increased pressure from vasoconstriction helps to open up the pupil, allowing for a better view of the internal structures of the eye.
3. Hypotension management: In some cases, phenylephrine may be given intravenously to treat low blood pressure (hypotension) during medical procedures like spinal anesthesia or septic shock. The vasoconstriction helps to increase blood pressure and improve perfusion of vital organs.

It is essential to use phenylephrine as directed, as improper usage can lead to adverse effects such as increased heart rate, hypertension, arrhythmias, and rebound congestion (when used as a nasal decongestant). Always consult with a healthcare professional for appropriate guidance on using this medication.

Myocardial reperfusion injury is a pathological process that occurs when blood flow is restored to the heart muscle (myocardium) after a period of ischemia or reduced oxygen supply, such as during a myocardial infarction (heart attack). The restoration of blood flow, although necessary to salvage the dying tissue, can itself cause further damage to the heart muscle. This paradoxical phenomenon is known as myocardial reperfusion injury.

The mechanisms behind myocardial reperfusion injury are complex and involve several processes, including:

1. Oxidative stress: The sudden influx of oxygen into the previously ischemic tissue leads to an overproduction of reactive oxygen species (ROS), which can damage cellular structures, such as proteins, lipids, and DNA.
2. Calcium overload: During reperfusion, there is an increase in calcium influx into the cardiomyocytes (heart muscle cells). This elevated intracellular calcium level can disrupt normal cellular functions, leading to further damage.
3. Inflammation: Reperfusion triggers an immune response, with the recruitment of inflammatory cells, such as neutrophils and monocytes, to the site of injury. These cells release cytokines and other mediators that can exacerbate tissue damage.
4. Mitochondrial dysfunction: The restoration of blood flow can cause mitochondria, the powerhouses of the cell, to malfunction, leading to the release of pro-apoptotic factors and contributing to cell death.
5. Vasoconstriction and microvascular obstruction: During reperfusion, there may be vasoconstriction of the small blood vessels (microvasculature) in the heart, which can further limit blood flow and contribute to tissue damage.

Myocardial reperfusion injury is a significant concern because it can negate some of the benefits of early reperfusion therapy, such as thrombolysis or primary percutaneous coronary intervention (PCI), used to treat acute myocardial infarction. Strategies to minimize myocardial reperfusion injury are an area of active research and include pharmacological interventions, ischemic preconditioning, and remote ischemic conditioning.

Anesthesia is a medical term that refers to the loss of sensation or awareness, usually induced by the administration of various drugs. It is commonly used during surgical procedures to prevent pain and discomfort. There are several types of anesthesia, including:

1. General anesthesia: This type of anesthesia causes a complete loss of consciousness and is typically used for major surgeries.
2. Regional anesthesia: This type of anesthesia numbs a specific area of the body, such as an arm or leg, while the patient remains conscious.
3. Local anesthesia: This type of anesthesia numbs a small area of the body, such as a cut or wound, and is typically used for minor procedures.

Anesthesia can be administered through various routes, including injection, inhalation, or topical application. The choice of anesthesia depends on several factors, including the type and duration of the procedure, the patient's medical history, and their overall health. Anesthesiologists are medical professionals who specialize in administering anesthesia and monitoring patients during surgical procedures to ensure their safety and comfort.

Cardiomyopathies are a group of diseases that affect the heart muscle, leading to mechanical and/or electrical dysfunction. The American Heart Association (AHA) defines cardiomyopathies as "a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not always) exhibit inappropriate ventricular hypertrophy or dilatation and frequently lead to heart failure."

There are several types of cardiomyopathies, including:

1. Dilated cardiomyopathy (DCM): This is the most common type of cardiomyopathy, characterized by an enlarged left ventricle and impaired systolic function, leading to heart failure.
2. Hypertrophic cardiomyopathy (HCM): In this type, there is abnormal thickening of the heart muscle, particularly in the septum between the two ventricles, which can obstruct blood flow and increase the risk of arrhythmias.
3. Restrictive cardiomyopathy (RCM): This is a rare form of cardiomyopathy characterized by stiffness of the heart muscle, impaired relaxation, and diastolic dysfunction, leading to reduced filling of the ventricles and heart failure.
4. Arrhythmogenic right ventricular cardiomyopathy (ARVC): In this type, there is replacement of the normal heart muscle with fatty or fibrous tissue, primarily affecting the right ventricle, which can lead to arrhythmias and sudden cardiac death.
5. Unclassified cardiomyopathies: These are conditions that do not fit into any of the above categories but still significantly affect the heart muscle and function.

Cardiomyopathies can be caused by genetic factors, acquired conditions (e.g., infections, toxins, or autoimmune disorders), or a combination of both. The diagnosis typically involves a comprehensive evaluation, including medical history, physical examination, electrocardiogram (ECG), echocardiography, cardiac magnetic resonance imaging (MRI), and sometimes genetic testing. Treatment depends on the type and severity of the condition but may include medications, lifestyle modifications, implantable devices, or even heart transplantation in severe cases.

Heart failure, systolic is a type of heart failure in which the heart's lower chambers, the ventricles, are not able to contract with enough force to pump an adequate amount of blood throughout the body. This means that the heart cannot effectively pump oxygenated blood to meet the body's needs, leading to symptoms such as shortness of breath, fatigue, and fluid buildup in the lungs and other parts of the body.

Systolic heart failure is often caused by damage to the heart muscle, such as from a heart attack or long-standing high blood pressure. Over time, this damage can weaken the heart muscle and make it harder for the ventricles to contract with enough force to pump blood efficiently.

Treatment for systolic heart failure typically involves medications to help improve heart function, reduce symptoms, and prevent further damage to the heart. Lifestyle changes, such as following a healthy diet, getting regular exercise, and quitting smoking, can also help manage this condition. In some cases, more advanced treatments such as implantable devices or heart transplantation may be necessary.

Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.

A cross-over study is a type of experimental design in which participants receive two or more interventions in a specific order. After a washout period, each participant receives the opposite intervention(s). The primary advantage of this design is that it controls for individual variability by allowing each participant to act as their own control.

In medical research, cross-over studies are often used to compare the efficacy or safety of two treatments. For example, a researcher might conduct a cross-over study to compare the effectiveness of two different medications for treating high blood pressure. Half of the participants would be randomly assigned to receive one medication first and then switch to the other medication after a washout period. The other half of the participants would receive the opposite order of treatments.

Cross-over studies can provide valuable insights into the relative merits of different interventions, but they also have some limitations. For example, they may not be suitable for studying conditions that are chronic or irreversible, as it may not be possible to completely reverse the effects of the first intervention before administering the second one. Additionally, carryover effects from the first intervention can confound the results if they persist into the second treatment period.

Overall, cross-over studies are a useful tool in medical research when used appropriately and with careful consideration of their limitations.

The Predictive Value of Tests, specifically the Positive Predictive Value (PPV) and Negative Predictive Value (NPV), are measures used in diagnostic tests to determine the probability that a positive or negative test result is correct.

Positive Predictive Value (PPV) is the proportion of patients with a positive test result who actually have the disease. It is calculated as the number of true positives divided by the total number of positive results (true positives + false positives). A higher PPV indicates that a positive test result is more likely to be a true positive, and therefore the disease is more likely to be present.

Negative Predictive Value (NPV) is the proportion of patients with a negative test result who do not have the disease. It is calculated as the number of true negatives divided by the total number of negative results (true negatives + false negatives). A higher NPV indicates that a negative test result is more likely to be a true negative, and therefore the disease is less likely to be present.

The predictive value of tests depends on the prevalence of the disease in the population being tested, as well as the sensitivity and specificity of the test. A test with high sensitivity and specificity will generally have higher predictive values than a test with low sensitivity and specificity. However, even a highly sensitive and specific test can have low predictive values if the prevalence of the disease is low in the population being tested.

Adrenergic beta-agonists are a class of medications that bind to and activate beta-adrenergic receptors, which are found in various tissues throughout the body. These receptors are part of the sympathetic nervous system and mediate the effects of the neurotransmitter norepinephrine (also called noradrenaline) and the hormone epinephrine (also called adrenaline).

When beta-agonists bind to these receptors, they stimulate a range of physiological responses, including relaxation of smooth muscle in the airways, increased heart rate and contractility, and increased metabolic rate. As a result, adrenergic beta-agonists are often used to treat conditions such as asthma, chronic obstructive pulmonary disease (COPD), and bronchitis, as they can help to dilate the airways and improve breathing.

There are several different types of beta-agonists, including short-acting and long-acting formulations. Short-acting beta-agonists (SABAs) are typically used for quick relief of symptoms, while long-acting beta-agonists (LABAs) are used for more sustained symptom control. Examples of adrenergic beta-agonists include albuterol (also known as salbutamol), terbutaline, formoterol, and salmeterol.

It's worth noting that while adrenergic beta-agonists can be very effective in treating respiratory conditions, they can also have side effects, particularly if used in high doses or for prolonged periods of time. These may include tremors, anxiety, palpitations, and increased blood pressure. As with any medication, it's important to use adrenergic beta-agonists only as directed by a healthcare professional.

Cardiac arrest, also known as heart arrest, is a medical condition where the heart suddenly stops beating or functioning properly. This results in the cessation of blood flow to the rest of the body, including the brain, leading to loss of consciousness and pulse. Cardiac arrest is often caused by electrical disturbances in the heart that disrupt its normal rhythm, known as arrhythmias. If not treated immediately with cardiopulmonary resuscitation (CPR) and defibrillation, it can lead to death or permanent brain damage due to lack of oxygen supply. It's important to note that a heart attack is different from cardiac arrest; a heart attack occurs when blood flow to a part of the heart is blocked, often by a clot, causing damage to the heart muscle, but the heart continues to beat. However, a heart attack can sometimes trigger a cardiac arrest.

Physiological monitoring is the continuous or intermittent observation and measurement of various body functions or parameters in a patient, with the aim of evaluating their health status, identifying any abnormalities or changes, and guiding clinical decision-making and treatment. This may involve the use of specialized medical equipment, such as cardiac monitors, pulse oximeters, blood pressure monitors, and capnographs, among others. The data collected through physiological monitoring can help healthcare professionals assess the effectiveness of treatments, detect complications early, and make timely adjustments to patient care plans.

Hypertension is a medical term used to describe abnormally high blood pressure in the arteries, often defined as consistently having systolic blood pressure (the top number in a blood pressure reading) over 130 mmHg and/or diastolic blood pressure (the bottom number) over 80 mmHg. It is also commonly referred to as high blood pressure.

Hypertension can be classified into two types: primary or essential hypertension, which has no identifiable cause and accounts for about 95% of cases, and secondary hypertension, which is caused by underlying medical conditions such as kidney disease, hormonal disorders, or use of certain medications.

If left untreated, hypertension can lead to serious health complications such as heart attack, stroke, heart failure, and chronic kidney disease. Therefore, it is important for individuals with hypertension to manage their condition through lifestyle modifications (such as healthy diet, regular exercise, stress management) and medication if necessary, under the guidance of a healthcare professional.

Consciousness is a complex and multifaceted concept that is difficult to define succinctly, but in a medical or neurological context, it generally refers to an individual's state of awareness and responsiveness to their surroundings. Consciousness involves a range of cognitive processes, including perception, thinking, memory, and attention, and it requires the integration of sensory information, language, and higher-order cognitive functions.

In medical terms, consciousness is often assessed using measures such as the Glasgow Coma Scale, which evaluates an individual's ability to open their eyes, speak, and move in response to stimuli. A coma is a state of deep unconsciousness where an individual is unable to respond to stimuli or communicate, while a vegetative state is a condition where an individual may have sleep-wake cycles and some automatic responses but lacks any meaningful awareness or cognitive function.

Disorders of consciousness can result from brain injury, trauma, infection, or other medical conditions that affect the functioning of the brainstem or cerebral cortex. The study of consciousness is a rapidly evolving field that involves researchers from various disciplines, including neuroscience, psychology, philosophy, and artificial intelligence.

Blood flow velocity is the speed at which blood travels through a specific part of the vascular system. It is typically measured in units of distance per time, such as centimeters per second (cm/s) or meters per second (m/s). Blood flow velocity can be affected by various factors, including cardiac output, vessel diameter, and viscosity of the blood. Measuring blood flow velocity is important in diagnosing and monitoring various medical conditions, such as heart disease, stroke, and peripheral vascular disease.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Ventricular remodeling is a structural adaptation process of the heart in response to stress or injury, such as myocardial infarction (heart attack) or pressure overload. This process involves changes in size, shape, and function of the ventricles (the lower chambers of the heart).

In ventricular remodeling, the heart muscle may thicken, enlarge, or become more stiff, leading to alterations in the pumping ability of the heart. These changes can ultimately result in cardiac dysfunction, heart failure, and an increased risk of arrhythmias (irregular heart rhythms).

Ventricular remodeling is often classified into two types:

1. Concentric remodeling: This occurs when the ventricular wall thickens (hypertrophy) without a significant increase in chamber size, leading to a decrease in the cavity volume and an increase in the thickness of the ventricular wall.
2. Eccentric remodeling: This involves an increase in both the ventricular chamber size and wall thickness due to the addition of new muscle cells (hyperplasia) or enlargement of existing muscle cells (hypertrophy). As a result, the overall shape of the ventricle becomes more spherical and less elliptical.

Both types of remodeling can negatively impact heart function and contribute to the development of heart failure. Close monitoring and appropriate treatment are essential for managing ventricular remodeling and preventing further complications.

An artificial heart is a mechanical device designed to replace the function of one or both ventricles of the natural human heart. It can be used as a temporary or permanent solution for patients with end-stage heart failure who are not candidates for heart transplantation. There are different types of artificial hearts, such as total artificial hearts and ventricular assist devices (VADs), which can help to pump blood throughout the body. These devices are typically composed of titanium and polyurethane materials and are powered by external electrical systems. They are designed to mimic the natural heart's action, helping to maintain adequate blood flow and oxygenation to vital organs.

Perfusion, in medical terms, refers to the process of circulating blood through the body's organs and tissues to deliver oxygen and nutrients and remove waste products. It is a measure of the delivery of adequate blood flow to specific areas or tissues in the body. Perfusion can be assessed using various methods, including imaging techniques like computed tomography (CT) scans, magnetic resonance imaging (MRI), and perfusion scintigraphy.

Perfusion is critical for maintaining proper organ function and overall health. When perfusion is impaired or inadequate, it can lead to tissue hypoxia, acidosis, and cell death, which can result in organ dysfunction or failure. Conditions that can affect perfusion include cardiovascular disease, shock, trauma, and certain surgical procedures.

The heart septum is the thick, muscular wall that divides the right and left sides of the heart. It consists of two main parts: the atrial septum, which separates the right and left atria (the upper chambers of the heart), and the ventricular septum, which separates the right and left ventricles (the lower chambers of the heart). A normal heart septum ensures that oxygen-rich blood from the lungs does not mix with oxygen-poor blood from the body. Any defect or abnormality in the heart septum is called a septal defect, which can lead to various congenital heart diseases.

The Valsalva maneuver is a medical procedure that involves forced exhalation against a closed airway, typically by closing one's mouth, pinching the nose shut, and then blowing. This maneuver increases the pressure in the chest and affects the heart's filling and pumping capabilities, as well as the pressures within the ears and eyes.

It is often used during medical examinations to test for conditions such as heart murmurs or to help clear the ears during changes in air pressure (like when scuba diving or flying). It can also be used to help diagnose or monitor conditions related to the autonomic nervous system, such as orthostatic hypotension or dysautonomia.

However, it's important to perform the Valsalva maneuver correctly and under medical supervision, as improper technique or overdoing it can lead to adverse effects like increased heart rate, changes in blood pressure, or even damage to the eardrum.

A chronic disease is a long-term medical condition that often progresses slowly over a period of years and requires ongoing management and care. These diseases are typically not fully curable, but symptoms can be managed to improve quality of life. Common chronic diseases include heart disease, stroke, cancer, diabetes, arthritis, and COPD (chronic obstructive pulmonary disease). They are often associated with advanced age, although they can also affect children and younger adults. Chronic diseases can have significant impacts on individuals' physical, emotional, and social well-being, as well as on healthcare systems and society at large.

Benzazepines are a class of heterocyclic compounds that contain a benzene fused to a diazepine ring. In the context of pharmaceuticals, benzazepines refer to a group of drugs with various therapeutic uses, such as antipsychotics and antidepressants. Some examples of benzazepine-derived drugs include clozapine, olanzapine, and loxoprofen. These drugs have complex mechanisms of action, often involving multiple receptor systems in the brain.

The term "diving" is generally not used in the context of medical definitions. However, when referring to diving in relation to a medical or physiological context, it usually refers to the act of submerging the body underwater, typically for activities such as swimming, snorkeling, or scuba diving.

In a medical or physiological sense, diving can have specific effects on the human body due to changes in pressure, temperature, and exposure to water. Some of these effects include:

* Changes in lung volume and gas exchange due to increased ambient pressure at depth.
* Decompression sickness (DCS) or nitrogen narcosis, which can occur when dissolved gases form bubbles in the body during ascent from a dive.
* Hypothermia, which can occur if the water is cold and the diver is not adequately insulated.
* Barotrauma, which can occur due to pressure differences between the middle ear or sinuses and the surrounding environment.
* Other medical conditions such as seizures or heart problems can also be exacerbated by diving.

It's important for divers to undergo proper training and certification, follow safe diving practices, and monitor their health before and after dives to minimize the risks associated with diving.

Vasodilator agents are pharmacological substances that cause the relaxation or widening of blood vessels by relaxing the smooth muscle in the vessel walls. This results in an increase in the diameter of the blood vessels, which decreases vascular resistance and ultimately reduces blood pressure. Vasodilators can be further classified based on their site of action:

1. Systemic vasodilators: These agents cause a generalized relaxation of the smooth muscle in the walls of both arteries and veins, resulting in a decrease in peripheral vascular resistance and preload (the volume of blood returning to the heart). Examples include nitroglycerin, hydralazine, and calcium channel blockers.
2. Arterial vasodilators: These agents primarily affect the smooth muscle in arterial vessel walls, leading to a reduction in afterload (the pressure against which the heart pumps blood). Examples include angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and direct vasodilators like sodium nitroprusside.
3. Venous vasodilators: These agents primarily affect the smooth muscle in venous vessel walls, increasing venous capacitance and reducing preload. Examples include nitroglycerin and other organic nitrates.

Vasodilator agents are used to treat various cardiovascular conditions such as hypertension, heart failure, angina, and pulmonary arterial hypertension. It is essential to monitor their use carefully, as excessive vasodilation can lead to orthostatic hypotension, reflex tachycardia, or fluid retention.

Analysis of Variance (ANOVA) is a statistical technique used to compare the means of two or more groups and determine whether there are any significant differences between them. It is a way to analyze the variance in a dataset to determine whether the variability between groups is greater than the variability within groups, which can indicate that the groups are significantly different from one another.

ANOVA is based on the concept of partitioning the total variance in a dataset into two components: variance due to differences between group means (also known as "between-group variance") and variance due to differences within each group (also known as "within-group variance"). By comparing these two sources of variance, ANOVA can help researchers determine whether any observed differences between groups are statistically significant, or whether they could have occurred by chance.

ANOVA is a widely used technique in many areas of research, including biology, psychology, engineering, and business. It is often used to compare the means of two or more experimental groups, such as a treatment group and a control group, to determine whether the treatment had a significant effect. ANOVA can also be used to compare the means of different populations or subgroups within a population, to identify any differences that may exist between them.

Heart injuries, also known as cardiac injuries, refer to any damage or harm caused to the heart muscle, valves, or surrounding structures. This can result from various causes such as blunt trauma (e.g., car accidents, falls), penetrating trauma (e.g., gunshot wounds, stabbing), or medical conditions like heart attacks (myocardial infarction) and infections (e.g., myocarditis, endocarditis).

Some common types of heart injuries include:

1. Contusions: Bruising of the heart muscle due to blunt trauma.
2. Myocardial infarctions: Damage to the heart muscle caused by insufficient blood supply, often due to blocked coronary arteries.
3. Cardiac rupture: A rare but life-threatening condition where the heart muscle tears or breaks open, usually resulting from severe trauma or complications from a myocardial infarction.
4. Valvular damage: Disruption of the heart valves' function due to injury or infection, leading to leakage (regurgitation) or narrowing (stenosis).
5. Pericardial injuries: Damage to the pericardium, the sac surrounding the heart, which can result in fluid accumulation (pericardial effusion), inflammation (pericarditis), or tamponade (compression of the heart by excess fluid).
6. Arrhythmias: Irregular heart rhythms caused by damage to the heart's electrical conduction system.

Timely diagnosis and appropriate treatment are crucial for managing heart injuries, as they can lead to severe complications or even be fatal if left untreated.

Respiratory rate is the number of breaths a person takes per minute. It is typically measured by counting the number of times the chest rises and falls in one minute. Normal respiratory rate at rest for an adult ranges from 12 to 20 breaths per minute. An increased respiratory rate (tachypnea) or decreased respiratory rate (bradypnea) can be a sign of various medical conditions, such as lung disease, heart failure, or neurological disorders. It is an important vital sign that should be regularly monitored in clinical settings.

Antihypertensive agents are a class of medications used to treat high blood pressure (hypertension). They work by reducing the force and rate of heart contractions, dilating blood vessels, or altering neurohormonal activation to lower blood pressure. Examples include diuretics, beta blockers, ACE inhibitors, ARBs, calcium channel blockers, and direct vasodilators. These medications may be used alone or in combination to achieve optimal blood pressure control.

An autonomic nerve block is a medical procedure that involves injecting a local anesthetic or other medication into or near the nerves that make up the autonomic nervous system. This type of nerve block is used to diagnose and treat certain medical conditions that affect the autonomic nervous system, such as neuropathy or complex regional pain syndrome (CRPS).

The autonomic nervous system is responsible for controlling many involuntary bodily functions, such as heart rate, blood pressure, digestion, and body temperature. It is made up of two parts: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for preparing the body for "fight or flight" responses, while the parasympathetic nervous system helps the body relax and rest.

An autonomic nerve block can be used to diagnose a problem with the autonomic nervous system by temporarily blocking the nerves' signals and observing how this affects the body's functions. It can also be used to treat pain or other symptoms caused by damage to the autonomic nerves. The injection is usually given in the area near the spine, and the specific location will depend on the nerves being targeted.

It is important to note that an autonomic nerve block is a medical procedure that should only be performed by a qualified healthcare professional. As with any medical procedure, there are risks and benefits associated with an autonomic nerve block, and it is important for patients to discuss these with their doctor before deciding whether this treatment is right for them.

Rheumatic Heart Disease (RHD) is defined as a chronic heart condition caused by damage to the heart valves due to untreated or inadequately treated streptococcal throat infection (strep throat). The immune system's response to this infection can mistakenly attack and damage the heart tissue, leading to inflammation and scarring of the heart valves. This damage can result in narrowing, leakage, or abnormal functioning of the heart valves, which can further lead to complications such as heart failure, stroke, or infective endocarditis.

RHD is a preventable and treatable condition if detected early and managed effectively. It primarily affects children and young adults in developing countries where access to healthcare and antibiotics for strep throat infections may be limited. Long-term management of RHD typically involves medications, regular monitoring, and sometimes surgical intervention to repair or replace damaged heart valves.

Cardiovascular diseases (CVDs) are a class of diseases that affect the heart and blood vessels. They are the leading cause of death globally, according to the World Health Organization (WHO). The term "cardiovascular disease" refers to a group of conditions that include:

1. Coronary artery disease (CAD): This is the most common type of heart disease and occurs when the arteries that supply blood to the heart become narrowed or blocked due to the buildup of cholesterol, fat, and other substances in the walls of the arteries. This can lead to chest pain, shortness of breath, or a heart attack.
2. Heart failure: This occurs when the heart is unable to pump blood efficiently to meet the body's needs. It can be caused by various conditions, including coronary artery disease, high blood pressure, and cardiomyopathy.
3. Stroke: A stroke occurs when the blood supply to a part of the brain is interrupted or reduced, often due to a clot or a ruptured blood vessel. This can cause brain damage or death.
4. Peripheral artery disease (PAD): This occurs when the arteries that supply blood to the limbs become narrowed or blocked, leading to pain, numbness, or weakness in the legs or arms.
5. Rheumatic heart disease: This is a complication of untreated strep throat and can cause damage to the heart valves, leading to heart failure or other complications.
6. Congenital heart defects: These are structural problems with the heart that are present at birth. They can range from mild to severe and may require medical intervention.
7. Cardiomyopathy: This is a disease of the heart muscle that makes it harder for the heart to pump blood efficiently. It can be caused by various factors, including genetics, infections, and certain medications.
8. Heart arrhythmias: These are abnormal heart rhythms that can cause the heart to beat too fast, too slow, or irregularly. They can lead to symptoms such as palpitations, dizziness, or fainting.
9. Valvular heart disease: This occurs when one or more of the heart valves become damaged or diseased, leading to problems with blood flow through the heart.
10. Aortic aneurysm and dissection: These are conditions that affect the aorta, the largest artery in the body. An aneurysm is a bulge in the aorta, while a dissection is a tear in the inner layer of the aorta. Both can be life-threatening if not treated promptly.

It's important to note that many of these conditions can be managed or treated with medical interventions such as medications, surgery, or lifestyle changes. If you have any concerns about your heart health, it's important to speak with a healthcare provider.

A heart valve prosthesis is a medical device that is implanted in the heart to replace a damaged or malfunctioning heart valve. The prosthetic valve can be made of biological tissue (such as from a pig or cow) or artificial materials (such as carbon or polyester). Its function is to allow for the proper directional flow of blood through the heart, opening and closing with each heartbeat to prevent backflow of blood.

There are several types of heart valve prostheses, including:

1. Mechanical valves: These are made entirely of artificial materials and have a longer lifespan than biological valves. However, they require the patient to take blood-thinning medication for the rest of their life to prevent blood clots from forming on the valve.
2. Bioprosthetic valves: These are made of biological tissue and typically last 10-15 years before needing replacement. They do not require the patient to take blood-thinning medication, but there is a higher risk of reoperation due to degeneration of the tissue over time.
3. Homografts or allografts: These are human heart valves that have been donated and preserved for transplantation. They have similar longevity to bioprosthetic valves and do not require blood-thinning medication.
4. Autografts: In this case, the patient's own pulmonary valve is removed and used to replace the damaged aortic valve. This procedure is called the Ross procedure and has excellent long-term results, but it requires advanced surgical skills and is not widely available.

The choice of heart valve prosthesis depends on various factors, including the patient's age, overall health, lifestyle, and personal preferences.

Adrenergic beta-1 receptor antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-1 receptors. These receptors are found primarily in the heart and kidneys, where they mediate various physiological responses such as increased heart rate, contractility, and conduction velocity, as well as renin release from the kidneys.

By blocking the action of adrenaline and noradrenaline on these receptors, beta blockers can help to reduce heart rate, lower blood pressure, decrease the force of heart contractions, and improve symptoms of angina (chest pain). They are commonly used to treat a variety of conditions, including hypertension, heart failure, arrhythmias, and certain types of tremors. Examples of beta blockers include metoprolol, atenolol, and propranolol.

Energy metabolism is the process by which living organisms produce and consume energy to maintain life. It involves a series of chemical reactions that convert nutrients from food, such as carbohydrates, fats, and proteins, into energy in the form of adenosine triphosphate (ATP).

The process of energy metabolism can be divided into two main categories: catabolism and anabolism. Catabolism is the breakdown of nutrients to release energy, while anabolism is the synthesis of complex molecules from simpler ones using energy.

There are three main stages of energy metabolism: glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation. Glycolysis occurs in the cytoplasm of the cell and involves the breakdown of glucose into pyruvate, producing a small amount of ATP and nicotinamide adenine dinucleotide (NADH). The citric acid cycle takes place in the mitochondria and involves the further breakdown of pyruvate to produce more ATP, NADH, and carbon dioxide. Oxidative phosphorylation is the final stage of energy metabolism and occurs in the inner mitochondrial membrane. It involves the transfer of electrons from NADH and other electron carriers to oxygen, which generates a proton gradient across the membrane. This gradient drives the synthesis of ATP, producing the majority of the cell's energy.

Overall, energy metabolism is a complex and essential process that allows organisms to grow, reproduce, and maintain their bodily functions. Disruptions in energy metabolism can lead to various diseases, including diabetes, obesity, and neurodegenerative disorders.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Sudden cardiac death (SCD) is a sudden, unexpected natural death caused by the cessation of cardiac activity. It is often caused by cardiac arrhythmias, particularly ventricular fibrillation, and is often associated with underlying heart disease, although it can occur in people with no known heart condition. SCD is typically defined as a natural death due to cardiac causes that occurs within one hour of the onset of symptoms, or if the individual was last seen alive in a normal state of health, it can be defined as occurring within 24 hours.

It's important to note that sudden cardiac arrest (SCA) is different from SCD, although they are related. SCA refers to the sudden cessation of cardiac activity, which if not treated immediately can lead to SCD.

A pulse is a medical term that refers to the tactile sensation of the heartbeat that can be felt in various parts of the body, most commonly at the wrist, neck, or groin. It is caused by the surge of blood through an artery as the heart pushes blood out into the body during systole (contraction). The pulse can provide important information about a person's heart rate, rhythm, and strength, which are all crucial vital signs that help healthcare professionals assess a patient's overall health and identify any potential medical issues.

In summary, a pulse is a palpable manifestation of the heartbeat felt in an artery due to the ejection of blood by the heart during systole.

Physical endurance is the ability of an individual to withstand and resist physical fatigue over prolonged periods of strenuous activity, exercise, or exertion. It involves the efficient functioning of various body systems, including the cardiovascular system (heart, blood vessels, and blood), respiratory system (lungs and airways), and musculoskeletal system (muscles, bones, tendons, ligaments, and cartilage).

Physical endurance is often measured in terms of aerobic capacity or stamina, which refers to the body's ability to supply oxygen to muscles during sustained physical activity. It can be improved through regular exercise, such as running, swimming, cycling, or weightlifting, that challenges the body's major muscle groups and raises the heart rate for extended periods.

Factors that influence physical endurance include genetics, age, sex, fitness level, nutrition, hydration, sleep quality, stress management, and overall health status. It is essential to maintain good physical endurance to perform daily activities efficiently, reduce the risk of chronic diseases, and enhance overall well-being.

Anoxia is a medical condition that refers to the absence or complete lack of oxygen supply in the body or a specific organ, tissue, or cell. This can lead to serious health consequences, including damage or death of cells and tissues, due to the vital role that oxygen plays in supporting cellular metabolism and energy production.

Anoxia can occur due to various reasons, such as respiratory failure, cardiac arrest, severe blood loss, carbon monoxide poisoning, or high altitude exposure. Prolonged anoxia can result in hypoxic-ischemic encephalopathy, a serious condition that can cause brain damage and long-term neurological impairments.

Medical professionals use various diagnostic tests, such as blood gas analysis, pulse oximetry, and electroencephalography (EEG), to assess oxygen levels in the body and diagnose anoxia. Treatment for anoxia typically involves addressing the underlying cause, providing supplemental oxygen, and supporting vital functions, such as breathing and circulation, to prevent further damage.

Cardiotocography (CTG) is a technical means of monitoring the fetal heart rate and uterine contractions during pregnancy, particularly during labor. It provides visual information about the fetal heart rate pattern and the frequency and intensity of uterine contractions. This helps healthcare providers assess the well-being of the fetus and the progression of labor.

The cardiotocograph records two main traces:

1. Fetal heart rate (FHR): It is recorded using an ultrasound transducer placed on the mother's abdomen. The normal fetal heart rate ranges from 120 to 160 beats per minute. Changes in the FHR pattern may indicate fetal distress, hypoxia, or other complications.

2. Uterine contractions: They are recorded using a pressure sensor (toco) placed on the mother's abdomen. The intensity and frequency of uterine contractions can be assessed to evaluate the progression of labor and the effect of contractions on fetal oxygenation.

Cardiotocography is widely used in obstetrics as a non-invasive method for monitoring fetal well-being during pregnancy and labor. However, it should always be interpreted cautiously by healthcare professionals, considering other factors like maternal and fetal conditions, medical history, and clinical presentation. Overinterpretation or misinterpretation of CTG traces can lead to unnecessary interventions or delays in recognizing actual fetal distress.

Adrenergic receptors are a type of G protein-coupled receptor that binds and responds to catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Beta adrenergic receptors (β-adrenergic receptors) are a subtype of adrenergic receptors that include three distinct subclasses: β1, β2, and β3. These receptors are widely distributed throughout the body and play important roles in various physiological functions, including cardiovascular regulation, bronchodilation, lipolysis, and glucose metabolism.

β1-adrenergic receptors are primarily located in the heart and regulate cardiac contractility, chronotropy (heart rate), and relaxation. β2-adrenergic receptors are found in various tissues, including the lungs, vascular smooth muscle, liver, and skeletal muscle. They mediate bronchodilation, vasodilation, glycogenolysis, and lipolysis. β3-adrenergic receptors are mainly expressed in adipose tissue, where they stimulate lipolysis and thermogenesis.

Agonists of β-adrenergic receptors include catecholamines like epinephrine and norepinephrine, as well as synthetic drugs such as dobutamine (a β1-selective agonist) and albuterol (a non-selective β2-agonist). Antagonists of β-adrenergic receptors are commonly used in the treatment of various conditions, including hypertension, angina pectoris, heart failure, and asthma. Examples of β-blockers include metoprolol (a β1-selective antagonist) and carvedilol (a non-selective β-blocker with additional α1-adrenergic receptor blocking activity).

Sympathomimetic drugs are substances that mimic or stimulate the actions of the sympathetic nervous system. The sympathetic nervous system is one of the two divisions of the autonomic nervous system, which regulates various automatic physiological functions in the body. The sympathetic nervous system's primary function is to prepare the body for the "fight-or-flight" response, which includes increasing heart rate, blood pressure, respiratory rate, and metabolism while decreasing digestive activity.

Sympathomimetic drugs can exert their effects through various mechanisms, including directly stimulating adrenergic receptors (alpha and beta receptors) or indirectly causing the release of norepinephrine and epinephrine from nerve endings. These drugs are used in various clinical settings to treat conditions such as asthma, nasal congestion, low blood pressure, and attention deficit hyperactivity disorder (ADHD). Examples of sympathomimetic drugs include epinephrine, norepinephrine, dopamine, dobutamine, albuterol, pseudoephedrine, and methylphenidate.

It is important to note that sympathomimetic drugs can also have adverse effects, particularly when used in high doses or in individuals with certain medical conditions. These adverse effects may include anxiety, tremors, palpitations, hypertension, arrhythmias, and seizures. Therefore, these medications should be used under the close supervision of a healthcare provider.

Sympatholytics are a class of drugs that block the action of the sympathetic nervous system, which is the part of the autonomic nervous system responsible for preparing the body for the "fight or flight" response. Sympatholytics achieve this effect by binding to and blocking alpha-adrenergic receptors or beta-adrenergic receptors located in various organs throughout the body, including the heart, blood vessels, lungs, gastrointestinal tract, and urinary system.

Examples of sympatholytic drugs include:

* Alpha blockers (e.g., prazosin, doxazosin)
* Beta blockers (e.g., propranolol, metoprolol)
* Centrally acting sympatholytics (e.g., clonidine, methyldopa)

Sympatholytics are used to treat a variety of medical conditions, including hypertension, angina, heart failure, arrhythmias, and certain neurological disorders. They may also be used to manage symptoms associated with anxiety or withdrawal from alcohol or other substances.

Prognosis is a medical term that refers to the prediction of the likely outcome or course of a disease, including the chances of recovery or recurrence, based on the patient's symptoms, medical history, physical examination, and diagnostic tests. It is an important aspect of clinical decision-making and patient communication, as it helps doctors and patients make informed decisions about treatment options, set realistic expectations, and plan for future care.

Prognosis can be expressed in various ways, such as percentages, categories (e.g., good, fair, poor), or survival rates, depending on the nature of the disease and the available evidence. However, it is important to note that prognosis is not an exact science and may vary depending on individual factors, such as age, overall health status, and response to treatment. Therefore, it should be used as a guide rather than a definitive forecast.

Clonidine is an medication that belongs to a class of drugs called centrally acting alpha-agonist hypotensives. It works by stimulating certain receptors in the brain and lowering the heart rate, which results in decreased blood pressure. Clonidine is commonly used to treat hypertension (high blood pressure), but it can also be used for other purposes such as managing withdrawal symptoms from opioids or alcohol, treating attention deficit hyperactivity disorder (ADHD), and preventing migraines. It can be taken orally in the form of tablets or transdermally through a patch applied to the skin. As with any medication, clonidine should be used under the guidance and supervision of a healthcare provider.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

"Age factors" refer to the effects, changes, or differences that age can have on various aspects of health, disease, and medical care. These factors can encompass a wide range of issues, including:

1. Physiological changes: As people age, their bodies undergo numerous physical changes that can affect how they respond to medications, illnesses, and medical procedures. For example, older adults may be more sensitive to certain drugs or have weaker immune systems, making them more susceptible to infections.
2. Chronic conditions: Age is a significant risk factor for many chronic diseases, such as heart disease, diabetes, cancer, and arthritis. As a result, age-related medical issues are common and can impact treatment decisions and outcomes.
3. Cognitive decline: Aging can also lead to cognitive changes, including memory loss and decreased decision-making abilities. These changes can affect a person's ability to understand and comply with medical instructions, leading to potential complications in their care.
4. Functional limitations: Older adults may experience physical limitations that impact their mobility, strength, and balance, increasing the risk of falls and other injuries. These limitations can also make it more challenging for them to perform daily activities, such as bathing, dressing, or cooking.
5. Social determinants: Age-related factors, such as social isolation, poverty, and lack of access to transportation, can impact a person's ability to obtain necessary medical care and affect their overall health outcomes.

Understanding age factors is critical for healthcare providers to deliver high-quality, patient-centered care that addresses the unique needs and challenges of older adults. By taking these factors into account, healthcare providers can develop personalized treatment plans that consider a person's age, physical condition, cognitive abilities, and social circumstances.

Doppler echocardiography is a type of ultrasound test that uses high-frequency sound waves to produce detailed images of the heart and its blood vessels. It measures the direction and speed of blood flow in the heart and major blood vessels leading to and from the heart. This helps to evaluate various conditions such as valve problems, congenital heart defects, and heart muscle diseases.

In Doppler echocardiography, a small handheld device called a transducer is placed on the chest, which emits sound waves that bounce off the heart and blood vessels. The transducer then picks up the returning echoes, which are processed by a computer to create moving images of the heart.

The Doppler effect is used to measure the speed and direction of blood flow. This occurs when the frequency of the sound waves changes as they bounce off moving objects, such as red blood cells. By analyzing these changes, the ultrasound machine can calculate the velocity and direction of blood flow in different parts of the heart.

Doppler echocardiography is a non-invasive test that does not require any needles or dyes. It is generally safe and painless, although patients may experience some discomfort from the pressure applied by the transducer on the chest. The test usually takes about 30 to 60 minutes to complete.

Diastolic heart failure, also known as heart failure with normal ejection fraction or heart failure with preserved ejection fraction, is a type of heart failure in which the heart's lower chambers, the ventricles, are unable to fill properly with blood during the diastole (relaxation) phase of the heartbeat. This is often due to increased stiffness of the heart muscle, which can be caused by conditions such as hypertension, aging, or diabetes. As a result, the heart cannot pump enough oxygen-rich blood to meet the body's needs, leading to symptoms such as shortness of breath, fatigue, and fluid retention. Diastolic dysfunction can be assessed by echocardiography, measuring the E/e' ratio, tissue doppler, and other diagnostics tools.

An artificial pacemaker is a medical device that uses electrical impulses to regulate the beating of the heart. It is typically used when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart rate is too slow or irregular. The pacemaker consists of a small generator that contains a battery and electronic circuits, which are connected to one or more electrodes that are placed in the heart.

The generator sends electrical signals through the electrodes to stimulate the heart muscle and cause it to contract, thereby maintaining a regular heart rhythm. Artificial pacemakers can be programmed to deliver electrical impulses at a specific rate or in response to the body's needs. They are typically implanted in the chest during a surgical procedure and can last for many years before needing to be replaced.

Artificial pacemakers are an effective treatment for various types of bradycardia, which is a heart rhythm disorder characterized by a slow heart rate. Pacemakers can significantly improve symptoms associated with bradycardia, such as fatigue, dizziness, shortness of breath, and fainting spells.

Body weight is the measure of the force exerted on a scale or balance by an object's mass, most commonly expressed in units such as pounds (lb) or kilograms (kg). In the context of medical definitions, body weight typically refers to an individual's total weight, which includes their skeletal muscle, fat, organs, and bodily fluids.

Healthcare professionals often use body weight as a basic indicator of overall health status, as it can provide insights into various aspects of a person's health, such as nutritional status, metabolic function, and risk factors for certain diseases. For example, being significantly underweight or overweight can increase the risk of developing conditions like malnutrition, diabetes, heart disease, and certain types of cancer.

It is important to note that body weight alone may not provide a complete picture of an individual's health, as it does not account for factors such as muscle mass, bone density, or body composition. Therefore, healthcare professionals often use additional measures, such as body mass index (BMI), waist circumference, and blood tests, to assess overall health status more comprehensively.

The American Heart Association (AHA) is a non-profit organization in the United States that aims to reduce disability and death from cardiovascular diseases and stroke, including heart disease and stroke. The AHA was founded in 1924 and is one of the oldest and largest voluntary organizations dedicated to fighting cardiovascular disease.

The AHA provides a range of services, including:

* Funding research into the causes, prevention, and treatment of heart disease and stroke
* Providing educational resources for healthcare professionals, patients, and the general public
* Advocating for policies that promote heart health and prevent heart disease and stroke
* Developing guidelines and standards for the diagnosis, treatment, and prevention of cardiovascular diseases

The AHA is funded through donations from individuals, corporations, and foundations. It operates with a volunteer board of directors and a professional staff. The organization has more than 3,400 volunteers and 70 local offices across the United States.

SHR (Spontaneously Hypertensive Rats) are an inbred strain of rats that were originally developed through selective breeding for high blood pressure. They are widely used as a model to study hypertension and related cardiovascular diseases, as well as neurological disorders such as stroke and dementia.

Inbred strains of animals are created by mating genetically identical individuals (siblings or offspring) for many generations, resulting in a population that is highly homozygous at all genetic loci. This means that the animals within an inbred strain are essentially genetically identical to one another, which makes them useful for studying the effects of specific genes or environmental factors on disease processes.

SHR rats develop high blood pressure spontaneously, without any experimental manipulation, and show many features of human hypertension, such as increased vascular resistance, left ventricular hypertrophy, and renal dysfunction. They also exhibit a number of behavioral abnormalities, including hyperactivity, impulsivity, and cognitive deficits, which make them useful for studying the neurological consequences of hypertension and other cardiovascular diseases.

Overall, inbred SHR rats are an important tool in biomedical research, providing a valuable model for understanding the genetic and environmental factors that contribute to hypertension and related disorders.

Brain Natriuretic Peptide (BNP) is a type of natriuretic peptide that is primarily produced in the heart, particularly in the ventricles. Although it was initially identified in the brain, hence its name, it is now known that the cardiac ventricles are the main source of BNP in the body.

BNP is released into the bloodstream in response to increased stretching or distension of the heart muscle cells due to conditions such as heart failure, hypertension, and myocardial infarction (heart attack). Once released, BNP binds to specific receptors in the kidneys, causing an increase in urine production and excretion of sodium, which helps reduce fluid volume and decrease the workload on the heart.

BNP also acts as a hormone that regulates various physiological functions, including blood pressure, cardiac remodeling, and inflammation. Measuring BNP levels in the blood is a useful diagnostic tool for detecting and monitoring heart failure, as higher levels of BNP are associated with more severe heart dysfunction.

Premature cardiac complexes, also known as premature heartbeats or premature ventricular contractions (PVCs), refer to extra or early heartbeats that originate in the lower chambers of the heart (the ventricles). These extra beats disrupt the normal rhythm and sequence of heartbeats, causing the heart to beat earlier than expected.

Premature cardiac complexes can occur in healthy individuals as well as those with heart disease. They are usually harmless and do not cause any symptoms, but in some cases, they may cause palpitations, skipped beats, or a fluttering sensation in the chest. In rare cases, frequent premature cardiac complexes can lead to more serious heart rhythm disorders or decreased heart function.

The diagnosis of premature cardiac complexes is usually made through an electrocardiogram (ECG) or Holter monitoring, which records the electrical activity of the heart over a period of time. Treatment is typically not necessary unless the premature complexes are frequent, symptomatic, or associated with underlying heart disease. In such cases, medications, cardioversion, or catheter ablation may be recommended.

Blood circulation, also known as cardiovascular circulation, refers to the process by which blood is pumped by the heart and circulated throughout the body through a network of blood vessels, including arteries, veins, and capillaries. This process ensures that oxygen and nutrients are delivered to cells and tissues, while waste products and carbon dioxide are removed.

The circulation of blood can be divided into two main parts: the pulmonary circulation and the systemic circulation. The pulmonary circulation involves the movement of blood between the heart and the lungs, where it picks up oxygen and releases carbon dioxide. The systemic circulation refers to the movement of blood between the heart and the rest of the body, delivering oxygen and nutrients to cells and tissues while picking up waste products for removal.

The heart plays a central role in blood circulation, acting as a pump that contracts and relaxes to move blood through the body. The contraction of the heart's left ventricle pushes oxygenated blood into the aorta, which then branches off into smaller arteries that carry blood throughout the body. The blood then flows through capillaries, where it exchanges oxygen and nutrients for waste products and carbon dioxide with surrounding cells and tissues. The deoxygenated blood is then collected in veins, which merge together to form larger vessels that eventually return the blood back to the heart's right atrium. From there, the blood is pumped into the lungs to pick up oxygen and release carbon dioxide, completing the cycle of blood circulation.

Parasympatholytics are a type of medication that blocks the action of the parasympathetic nervous system. The parasympathetic nervous system is responsible for the body's rest and digest response, which includes slowing the heart rate, increasing intestinal and glandular activity, and promoting urination and defecation.

Parasympatholytics work by selectively binding to muscarinic receptors, which are found in various organs throughout the body, including the heart, lungs, and digestive system. By blocking these receptors, parasympatholytics can cause a range of effects, such as an increased heart rate, decreased glandular secretions, and reduced intestinal motility.

Some common examples of parasympatholytics include atropine, scopolamine, and ipratropium. These medications are often used to treat conditions such as bradycardia (slow heart rate), excessive salivation, and gastrointestinal cramping or diarrhea. However, because they can have significant side effects, parasympatholytics are typically used only when necessary and under the close supervision of a healthcare provider.

Respiratory mechanics refers to the biomechanical properties and processes that involve the movement of air through the respiratory system during breathing. It encompasses the mechanical behavior of the lungs, chest wall, and the muscles of respiration, including the diaphragm and intercostal muscles.

Respiratory mechanics includes several key components:

1. **Compliance**: The ability of the lungs and chest wall to expand and recoil during breathing. High compliance means that the structures can easily expand and recoil, while low compliance indicates greater resistance to expansion and recoil.
2. **Resistance**: The opposition to airflow within the respiratory system, primarily due to the friction between the air and the airway walls. Airway resistance is influenced by factors such as airway diameter, length, and the viscosity of the air.
3. **Lung volumes and capacities**: These are the amounts of air present in the lungs during different phases of the breathing cycle. They include tidal volume (the amount of air inspired or expired during normal breathing), inspiratory reserve volume (additional air that can be inspired beyond the tidal volume), expiratory reserve volume (additional air that can be exhaled beyond the tidal volume), and residual volume (the air remaining in the lungs after a forced maximum exhalation).
4. **Work of breathing**: The energy required to overcome the resistance and elastic forces during breathing. This work is primarily performed by the respiratory muscles, which contract to generate negative intrathoracic pressure and expand the chest wall, allowing air to flow into the lungs.
5. **Pressure-volume relationships**: These describe how changes in lung volume are associated with changes in pressure within the respiratory system. Important pressure components include alveolar pressure (the pressure inside the alveoli), pleural pressure (the pressure between the lungs and the chest wall), and transpulmonary pressure (the difference between alveolar and pleural pressures).

Understanding respiratory mechanics is crucial for diagnosing and managing various respiratory disorders, such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

General anesthesia is a state of controlled unconsciousness, induced by administering various medications, that eliminates awareness, movement, and pain sensation during medical procedures. It involves the use of a combination of intravenous and inhaled drugs to produce a reversible loss of consciousness, allowing patients to undergo surgical or diagnostic interventions safely and comfortably. The depth and duration of anesthesia are carefully monitored and adjusted throughout the procedure by an anesthesiologist or certified registered nurse anesthetist (CRNA) to ensure patient safety and optimize recovery. General anesthesia is typically used for more extensive surgical procedures, such as open-heart surgery, major orthopedic surgeries, and neurosurgery.

Ventricular Premature Complexes (VPCs), also known as Ventricular Extrasystoles or Premature Ventricular Contractions (PVCs), are extra heartbeats that originate in the ventricles, the lower chambers of the heart. These premature beats disrupt the normal sequence of electrical impulses in the heart and cause the ventricles to contract earlier than they should.

VPCs can result in a noticeable "skipped" or "extra" beat sensation, often followed by a stronger beat as the heart returns to its regular rhythm. They may occur occasionally in healthy individuals with no underlying heart condition, but frequent VPCs could indicate an underlying issue such as heart disease, electrolyte imbalance, or digitalis toxicity. In some cases, VPCs can be harmless and require no treatment; however, if they are frequent or associated with structural heart problems, further evaluation and management may be necessary to prevent potential complications like reduced cardiac output or heart failure.

Arterial pressure is the pressure exerted by the blood on the walls of the arteries during its flow through them. It is usually measured in millimeters of mercury (mmHg) and is expressed as two numbers: systolic and diastolic pressures. Systolic pressure is the higher value, representing the pressure when the heart contracts and pushes blood into the arteries. Diastolic pressure is the lower value, representing the pressure when the heart relaxes and fills with blood. A normal resting blood pressure for adults is typically around 120/80 mmHg.

Risk assessment in the medical context refers to the process of identifying, evaluating, and prioritizing risks to patients, healthcare workers, or the community related to healthcare delivery. It involves determining the likelihood and potential impact of adverse events or hazards, such as infectious diseases, medication errors, or medical devices failures, and implementing measures to mitigate or manage those risks. The goal of risk assessment is to promote safe and high-quality care by identifying areas for improvement and taking action to minimize harm.

The atrioventricular (AV) node is a critical part of the electrical conduction system of the heart. It is a small cluster of specialized cardiac muscle cells located in the lower interatrial septum, near the opening of the coronary sinus. The AV node receives electrical impulses from the sinoatrial node (the heart's natural pacemaker) via the internodal pathways and delays their transmission for a brief period before transmitting them to the bundle of His and then to the ventricles. This delay allows the atria to contract and empty their contents into the ventricles before the ventricles themselves contract, ensuring efficient pumping of blood throughout the body.

The AV node plays an essential role in maintaining a normal heart rhythm, as it can also function as a backup pacemaker if the sinoatrial node fails to generate impulses. However, certain heart conditions or medications can affect the AV node's function and lead to abnormal heart rhythms, such as atrioventricular block or atrial tachycardia.

Intravenous injections are a type of medical procedure where medication or fluids are administered directly into a vein using a needle and syringe. This route of administration is also known as an IV injection. The solution injected enters the patient's bloodstream immediately, allowing for rapid absorption and onset of action. Intravenous injections are commonly used to provide quick relief from symptoms, deliver medications that are not easily absorbed by other routes, or administer fluids and electrolytes in cases of dehydration or severe illness. It is important that intravenous injections are performed using aseptic technique to minimize the risk of infection.

Atrial function in a medical context refers to the role and performance of the two upper chambers of the heart, known as the atria. The main functions of the atria are to receive blood from the veins and help pump it into the ventricles, which are the lower pumping chambers of the heart.

The atria contract in response to electrical signals generated by the sinoatrial node, which is the heart's natural pacemaker. This contraction helps to fill the ventricles with blood before they contract and pump blood out to the rest of the body. Atrial function can be assessed through various diagnostic tests, such as echocardiograms or electrocardiograms (ECGs), which can help identify any abnormalities in atrial structure or electrical activity that may affect heart function.

nitroprusside (ni-troe-rus-ide)

A rapid-acting vasodilator used in the management of severe hypertension, acute heart failure, and to reduce afterload in patients undergoing cardiac surgery. It is a potent arterial and venous dilator that decreases preload and afterload, thereby reducing myocardial oxygen demand. Nitroprusside is metabolized to cyanide, which must be monitored closely during therapy to prevent toxicity.

Pharmacologic class: Peripheral vasodilators

Therapeutic class: Antihypertensives, Vasodilators

Medical Categories: Cardiovascular Drugs, Hypertension Agents

Coronary circulation refers to the circulation of blood in the coronary vessels, which supply oxygenated blood to the heart muscle (myocardium) and drain deoxygenated blood from it. The coronary circulation system includes two main coronary arteries - the left main coronary artery and the right coronary artery - that branch off from the aorta just above the aortic valve. These arteries further divide into smaller branches, which supply blood to different regions of the heart muscle.

The left main coronary artery divides into two branches: the left anterior descending (LAD) artery and the left circumflex (LCx) artery. The LAD supplies blood to the front and sides of the heart, while the LCx supplies blood to the back and sides of the heart. The right coronary artery supplies blood to the lower part of the heart, including the right ventricle and the bottom portion of the left ventricle.

The veins that drain the heart muscle include the great cardiac vein, the middle cardiac vein, and the small cardiac vein, which merge to form the coronary sinus. The coronary sinus empties into the right atrium, allowing deoxygenated blood to enter the right side of the heart and be pumped to the lungs for oxygenation.

Coronary circulation is essential for maintaining the health and function of the heart muscle, as it provides the necessary oxygen and nutrients required for proper contraction and relaxation of the myocardium. Any disruption or blockage in the coronary circulation system can lead to serious consequences, such as angina, heart attack, or even death.

The heart conduction system is a group of specialized cardiac muscle cells that generate and conduct electrical impulses to coordinate the contraction of the heart chambers. The main components of the heart conduction system include:

1. Sinoatrial (SA) node: Also known as the sinus node, it is located in the right atrium near the entrance of the superior vena cava and functions as the primary pacemaker of the heart. It sets the heart rate by generating electrical impulses at regular intervals.
2. Atrioventricular (AV) node: Located in the interatrial septum, near the opening of the coronary sinus, it serves as a relay station for electrical signals between the atria and ventricles. The AV node delays the transmission of impulses to allow the atria to contract before the ventricles.
3. Bundle of His: A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles. It divides into two main branches, the right and left bundle branches, which further divide into smaller Purkinje fibers.
4. Right and left bundle branches: These are extensions of the Bundle of His that transmit electrical impulses to the respective right and left ventricular myocardium. They consist of specialized conducting tissue with large diameters and minimal resistance, allowing for rapid conduction of electrical signals.
5. Purkinje fibers: Fine, branching fibers that arise from the bundle branches and spread throughout the ventricular myocardium. They are responsible for transmitting electrical impulses to the working cardiac muscle cells, triggering coordinated ventricular contraction.

In summary, the heart conduction system is a complex network of specialized muscle cells responsible for generating and conducting electrical signals that coordinate the contraction of the atria and ventricles, ensuring efficient blood flow throughout the body.

I apologize for the confusion, but "physical conditioning" is not a term that is typically used in the context of animals in veterinary medicine or animal sciences. The term "physical conditioning" is more commonly used to describe the process of improving an individual's physical fitness through exercise and training.

However, in animal science, the concept of "training" or "exercising" animals may refer to the process of teaching them specific behaviors or skills, improving their physical abilities, or promoting their overall health and well-being. This might involve activities such as providing opportunities for regular exercise, engaging in play, or using positive reinforcement techniques to teach animals new skills or modify their behavior.

If you have any further questions about animal care or training, I would be happy to try to help!

Intravenous (IV) infusion is a medical procedure in which liquids, such as medications, nutrients, or fluids, are delivered directly into a patient's vein through a needle or a catheter. This route of administration allows for rapid absorption and distribution of the infused substance throughout the body. IV infusions can be used for various purposes, including resuscitation, hydration, nutrition support, medication delivery, and blood product transfusion. The rate and volume of the infusion are carefully controlled to ensure patient safety and efficacy of treatment.

Atrial fibrillation (A-tre-al fi-bru-la'shun) is a type of abnormal heart rhythm characterized by rapid and irregular beating of the atria, the upper chambers of the heart. In this condition, the electrical signals that coordinate heartbeats don't function properly, causing the atria to quiver instead of contracting effectively. As a result, blood may not be pumped efficiently into the ventricles, which can lead to blood clots, stroke, and other complications. Atrial fibrillation is a common type of arrhythmia and can cause symptoms such as palpitations, shortness of breath, fatigue, and dizziness. It can be caused by various factors, including heart disease, high blood pressure, age, and genetics. Treatment options include medications, electrical cardioversion, and surgical procedures to restore normal heart rhythm.

A kidney, in medical terms, is one of two bean-shaped organs located in the lower back region of the body. They are essential for maintaining homeostasis within the body by performing several crucial functions such as:

1. Regulation of water and electrolyte balance: Kidneys help regulate the amount of water and various electrolytes like sodium, potassium, and calcium in the bloodstream to maintain a stable internal environment.

2. Excretion of waste products: They filter waste products from the blood, including urea (a byproduct of protein metabolism), creatinine (a breakdown product of muscle tissue), and other harmful substances that result from normal cellular functions or external sources like medications and toxins.

3. Endocrine function: Kidneys produce several hormones with important roles in the body, such as erythropoietin (stimulates red blood cell production), renin (regulates blood pressure), and calcitriol (activated form of vitamin D that helps regulate calcium homeostasis).

4. pH balance regulation: Kidneys maintain the proper acid-base balance in the body by excreting either hydrogen ions or bicarbonate ions, depending on whether the blood is too acidic or too alkaline.

5. Blood pressure control: The kidneys play a significant role in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS), which constricts blood vessels and promotes sodium and water retention to increase blood volume and, consequently, blood pressure.

Anatomically, each kidney is approximately 10-12 cm long, 5-7 cm wide, and 3 cm thick, with a weight of about 120-170 grams. They are surrounded by a protective layer of fat and connected to the urinary system through the renal pelvis, ureters, bladder, and urethra.

Digoxin is a medication that belongs to a class of drugs called cardiac glycosides. It is used to treat various heart conditions, such as heart failure and atrial fibrillation, by helping the heart beat stronger and more regularly. Digoxin works by inhibiting the sodium-potassium pump in heart muscle cells, which leads to an increase in intracellular calcium and a strengthening of heart contractions. It is important to monitor digoxin levels closely, as too much can lead to toxicity and serious side effects.

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.

In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.

Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.

Psychological stress is the response of an individual's mind and body to challenging or demanding situations. It can be defined as a state of emotional and physical tension resulting from adversity, demand, or change. This response can involve a variety of symptoms, including emotional, cognitive, behavioral, and physiological components.

Emotional responses may include feelings of anxiety, fear, anger, sadness, or frustration. Cognitive responses might involve difficulty concentrating, racing thoughts, or negative thinking patterns. Behaviorally, psychological stress can lead to changes in appetite, sleep patterns, social interactions, and substance use. Physiologically, the body's "fight-or-flight" response is activated, leading to increased heart rate, blood pressure, muscle tension, and other symptoms.

Psychological stress can be caused by a wide range of factors, including work or school demands, financial problems, relationship issues, traumatic events, chronic illness, and major life changes. It's important to note that what causes stress in one person may not cause stress in another, as individual perceptions and coping mechanisms play a significant role.

Chronic psychological stress can have negative effects on both mental and physical health, increasing the risk of conditions such as anxiety disorders, depression, heart disease, diabetes, and autoimmune diseases. Therefore, it's essential to identify sources of stress and develop effective coping strategies to manage and reduce its impact.

Nitroglycerin, also known as glyceryl trinitrate, is a medication used primarily for the treatment of angina pectoris (chest pain due to coronary artery disease) and hypertensive emergencies (severe high blood pressure). It belongs to a class of drugs called nitrates or organic nitrites.

Nitroglycerin works by relaxing and dilating the smooth muscle in blood vessels, which leads to decreased workload on the heart and increased oxygen delivery to the myocardium (heart muscle). This results in reduced symptoms of angina and improved cardiac function during hypertensive emergencies.

The drug is available in various forms, including sublingual tablets, sprays, transdermal patches, ointments, and intravenous solutions. The choice of formulation depends on the specific clinical situation and patient needs. Common side effects of nitroglycerin include headache, dizziness, and hypotension (low blood pressure).

Dobutamine is a synthetic catecholamine used in medical treatment, specifically as a positive inotrope and vasodilator. It works by stimulating the beta-1 adrenergic receptors of the heart, thereby increasing its contractility and stroke volume. This results in an improved cardiac output, making dobutamine beneficial in treating heart failure, cardiogenic shock, and other conditions where heart function is compromised.

It's important to note that dobutamine should be administered under strict medical supervision due to its potential to cause adverse effects such as arrhythmias, hypotension, or hypertension. The dosage, frequency, and duration of administration are determined by the patient's specific condition and response to treatment.

A vagotomy is a surgical procedure that involves cutting or blocking the vagus nerve, which is a parasympathetic nerve that runs from the brainstem to the abdomen and helps regulate many bodily functions such as heart rate, gastrointestinal motility, and digestion. In particular, vagotomy is often performed as a treatment for peptic ulcers, as it can help reduce gastric acid secretion.

There are several types of vagotomy procedures, including:

1. Truncal vagotomy: This involves cutting the main trunks of the vagus nerve as they enter the abdomen. It is a more extensive procedure that reduces gastric acid secretion significantly but can also lead to side effects such as delayed gastric emptying and diarrhea.
2. Selective vagotomy: This involves cutting only the branches of the vagus nerve that supply the stomach, leaving the rest of the nerve intact. It is a less extensive procedure that reduces gastric acid secretion while minimizing side effects.
3. Highly selective vagotomy (HSV): Also known as parietal cell vagotomy, this involves cutting only the branches of the vagus nerve that supply the acid-secreting cells in the stomach. It is a highly targeted procedure that reduces gastric acid secretion while minimizing side effects such as delayed gastric emptying and diarrhea.

Vagotomy is typically performed using laparoscopic or open surgical techniques, depending on the patient's individual needs and the surgeon's preference. While vagotomy can be effective in treating peptic ulcers, it is not commonly performed today due to the development of less invasive treatments such as proton pump inhibitors (PPIs) that reduce gastric acid secretion without surgery.

A cohort study is a type of observational study in which a group of individuals who share a common characteristic or exposure are followed up over time to determine the incidence of a specific outcome or outcomes. The cohort, or group, is defined based on the exposure status (e.g., exposed vs. unexposed) and then monitored prospectively to assess for the development of new health events or conditions.

Cohort studies can be either prospective or retrospective in design. In a prospective cohort study, participants are enrolled and followed forward in time from the beginning of the study. In contrast, in a retrospective cohort study, researchers identify a cohort that has already been assembled through medical records, insurance claims, or other sources and then look back in time to assess exposure status and health outcomes.

Cohort studies are useful for establishing causality between an exposure and an outcome because they allow researchers to observe the temporal relationship between the two. They can also provide information on the incidence of a disease or condition in different populations, which can be used to inform public health policy and interventions. However, cohort studies can be expensive and time-consuming to conduct, and they may be subject to bias if participants are not representative of the population or if there is loss to follow-up.

Renin is a medically recognized term and it is defined as:

"A protein (enzyme) that is produced and released by specialized cells (juxtaglomerular cells) in the kidney. Renin is a key component of the renin-angiotensin-aldosterone system (RAAS), which helps regulate blood pressure and fluid balance in the body.

When the kidney detects a decrease in blood pressure or a reduction in sodium levels, it releases renin into the bloodstream. Renin then acts on a protein called angiotensinogen, converting it to angiotensin I. Angiotensin-converting enzyme (ACE) subsequently converts angiotensin I to angiotensin II, which is a potent vasoconstrictor that narrows blood vessels and increases blood pressure.

Additionally, angiotensin II stimulates the adrenal glands to release aldosterone, a hormone that promotes sodium reabsorption in the kidneys and increases water retention, further raising blood pressure.

Therefore, renin plays a critical role in maintaining proper blood pressure and electrolyte balance in the body."

"Cold temperature" is a relative term and its definition can vary depending on the context. In general, it refers to temperatures that are lower than those normally experienced or preferred by humans and other warm-blooded animals. In a medical context, cold temperature is often defined as an environmental temperature that is below 16°C (60.8°F).

Exposure to cold temperatures can have various physiological effects on the human body, such as vasoconstriction of blood vessels near the skin surface, increased heart rate and metabolic rate, and shivering, which helps to generate heat and maintain body temperature. Prolonged exposure to extreme cold temperatures can lead to hypothermia, a potentially life-threatening condition characterized by a drop in core body temperature below 35°C (95°F).

It's worth noting that some people may have different sensitivities to cold temperatures due to factors such as age, health status, and certain medical conditions. For example, older adults, young children, and individuals with circulatory or neurological disorders may be more susceptible to the effects of cold temperatures.

A biological marker, often referred to as a biomarker, is a measurable indicator that reflects the presence or severity of a disease state, or a response to a therapeutic intervention. Biomarkers can be found in various materials such as blood, tissues, or bodily fluids, and they can take many forms, including molecular, histologic, radiographic, or physiological measurements.

In the context of medical research and clinical practice, biomarkers are used for a variety of purposes, such as:

1. Diagnosis: Biomarkers can help diagnose a disease by indicating the presence or absence of a particular condition. For example, prostate-specific antigen (PSA) is a biomarker used to detect prostate cancer.
2. Monitoring: Biomarkers can be used to monitor the progression or regression of a disease over time. For instance, hemoglobin A1c (HbA1c) levels are monitored in diabetes patients to assess long-term blood glucose control.
3. Predicting: Biomarkers can help predict the likelihood of developing a particular disease or the risk of a negative outcome. For example, the presence of certain genetic mutations can indicate an increased risk for breast cancer.
4. Response to treatment: Biomarkers can be used to evaluate the effectiveness of a specific treatment by measuring changes in the biomarker levels before and after the intervention. This is particularly useful in personalized medicine, where treatments are tailored to individual patients based on their unique biomarker profiles.

It's important to note that for a biomarker to be considered clinically valid and useful, it must undergo rigorous validation through well-designed studies, including demonstrating sensitivity, specificity, reproducibility, and clinical relevance.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

Left ventricular hypertrophy (LVH) is a medical condition in which the left ventricle of the heart undergoes an enlargement or thickening of its muscle wall. The left ventricle is the main pumping chamber of the heart that supplies oxygenated blood to the rest of the body.

In response to increased workload, such as hypertension (high blood pressure), aortic valve stenosis, or athletic training, the left ventricular muscle may thicken and enlarge. This process is called "hypertrophy." While some degree of hypertrophy can be adaptive in athletes, significant or excessive hypertrophy can lead to impaired relaxation and filling of the left ventricle during diastole, reduced pumping capacity, and decreased compliance of the chamber.

Left ventricular hypertrophy is often asymptomatic initially but can increase the risk of various cardiovascular complications such as heart failure, arrhythmias, myocardial infarction (heart attack), and sudden cardiac death over time. It is typically diagnosed through imaging techniques like echocardiography or cardiac MRI and confirmed by measuring the thickness of the left ventricular wall.

A case-control study is an observational research design used to identify risk factors or causes of a disease or health outcome. In this type of study, individuals with the disease or condition (cases) are compared with similar individuals who do not have the disease or condition (controls). The exposure history or other characteristics of interest are then compared between the two groups to determine if there is an association between the exposure and the disease.

Case-control studies are often used when it is not feasible or ethical to conduct a randomized controlled trial, as they can provide valuable insights into potential causes of diseases or health outcomes in a relatively short period of time and at a lower cost than other study designs. However, because case-control studies rely on retrospective data collection, they are subject to biases such as recall bias and selection bias, which can affect the validity of the results. Therefore, it is important to carefully design and conduct case-control studies to minimize these potential sources of bias.

Physiological stress is a response of the body to a demand or threat that disrupts homeostasis and activates the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis. This results in the release of stress hormones such as adrenaline, cortisol, and noradrenaline, which prepare the body for a "fight or flight" response. Increased heart rate, rapid breathing, heightened sensory perception, and increased alertness are some of the physiological changes that occur during this response. Chronic stress can have negative effects on various bodily functions, including the immune, cardiovascular, and nervous systems.

The forearm is the region of the upper limb between the elbow and the wrist. It consists of two bones, the radius and ulna, which are located side by side and run parallel to each other. The forearm is responsible for movements such as flexion, extension, supination, and pronation of the hand and wrist.

I'm sorry for any confusion, but "Linear Models" is actually a term from the field of statistics and machine learning, rather than medicine. A linear model is a type of statistical model that is used to analyze the relationship between two or more variables. In a linear model, the relationship between the dependent variable (the outcome or result) and the independent variable(s) (the factors being studied) is assumed to be linear, meaning that it can be described by a straight line on a graph.

The equation for a simple linear model with one independent variable (x) and one dependent variable (y) looks like this:

y = β0 + β1*x + ε

In this equation, β0 is the y-intercept or the value of y when x equals zero, β1 is the slope or the change in y for each unit increase in x, and ε is the error term or the difference between the actual values of y and the predicted values of y based on the linear model.

Linear models are widely used in medical research to study the relationship between various factors (such as exposure to a risk factor or treatment) and health outcomes (such as disease incidence or mortality). They can also be used to adjust for confounding variables, which are factors that may influence both the independent variable and the dependent variable, and thus affect the observed relationship between them.

The carotid sinus is a small, dilated area located at the bifurcation (or fork) of the common carotid artery into the internal and external carotid arteries. It is a baroreceptor region, which means it contains specialized sensory nerve endings that can detect changes in blood pressure. When the blood pressure increases, the walls of the carotid sinus stretch, activating these nerve endings and sending signals to the brain. The brain then responds by reducing the heart rate and relaxing the blood vessels, which helps to lower the blood pressure back to normal.

The carotid sinus is an important part of the body's autonomic nervous system, which regulates various involuntary functions such as heart rate, blood pressure, and digestion. It plays a crucial role in maintaining cardiovascular homeostasis and preventing excessive increases in blood pressure that could potentially damage vital organs.

Regression analysis is a statistical technique used in medicine, as well as in other fields, to examine the relationship between one or more independent variables (predictors) and a dependent variable (outcome). It allows for the estimation of the average change in the outcome variable associated with a one-unit change in an independent variable, while controlling for the effects of other independent variables. This technique is often used to identify risk factors for diseases or to evaluate the effectiveness of medical interventions. In medical research, regression analysis can be used to adjust for potential confounding variables and to quantify the relationship between exposures and health outcomes. It can also be used in predictive modeling to estimate the probability of a particular outcome based on multiple predictors.

A newborn infant is a baby who is within the first 28 days of life. This period is also referred to as the neonatal period. Newborns require specialized care and attention due to their immature bodily systems and increased vulnerability to various health issues. They are closely monitored for signs of well-being, growth, and development during this critical time.

The medulla oblongata is a part of the brainstem that is located in the posterior portion of the brainstem and continues with the spinal cord. It plays a vital role in controlling several critical bodily functions, such as breathing, heart rate, and blood pressure. The medulla oblongata also contains nerve pathways that transmit sensory information from the body to the brain and motor commands from the brain to the muscles. Additionally, it is responsible for reflexes such as vomiting, swallowing, coughing, and sneezing.

Blood volume refers to the total amount of blood present in an individual's circulatory system at any given time. It is the combined volume of both the plasma (the liquid component of blood) and the formed elements (such as red and white blood cells and platelets) in the blood. In a healthy adult human, the average blood volume is approximately 5 liters (or about 1 gallon). However, blood volume can vary depending on several factors, including age, sex, body weight, and overall health status.

Blood volume plays a critical role in maintaining proper cardiovascular function, as it affects blood pressure, heart rate, and the delivery of oxygen and nutrients to tissues throughout the body. Changes in blood volume can have significant impacts on an individual's health and may be associated with various medical conditions, such as dehydration, hemorrhage, heart failure, and liver disease. Accurate measurement of blood volume is essential for diagnosing and managing these conditions, as well as for guiding treatment decisions in clinical settings.

Denervation is a medical term that refers to the loss or removal of nerve supply to an organ or body part. This can occur as a result of surgical intervention, injury, or disease processes that damage the nerves leading to the affected area. The consequences of denervation depend on the specific organ or tissue involved, but generally, it can lead to changes in function, sensation, and muscle tone. For example, denervation of a skeletal muscle can cause weakness, atrophy, and altered reflexes. Similarly, denervation of an organ such as the heart can lead to abnormalities in heart rate and rhythm. In some cases, denervation may be intentional, such as during surgical procedures aimed at treating chronic pain or spasticity.

Ventricular Fibrillation (VF) is a type of cardiac arrhythmia, which is an abnormal heart rhythm. In VF, the ventricles, which are the lower chambers of the heart, beat in a rapid and unorganized manner. This results in the heart being unable to pump blood effectively to the rest of the body, leading to immediate circulatory collapse and cardiac arrest if not treated promptly. It is often caused by underlying heart conditions such as coronary artery disease, structural heart problems, or electrolyte imbalances. VF is a medical emergency that requires immediate defibrillation to restore a normal heart rhythm.

Physical fitness is a state of being able to perform various physical activities that require endurance, strength, flexibility, balance, and coordination. According to the American Heart Association (AHA), physical fitness is defined as "a set of attributes that people have or achieve that relates to the ability to perform physical activity."

The AHA identifies five components of physical fitness:

1. Cardiorespiratory endurance: The ability of the heart, lungs, and blood vessels to supply oxygen to muscles during sustained physical activity.
2. Muscular strength: The amount of force a muscle can exert in a single effort.
3. Muscular endurance: The ability of a muscle or group of muscles to sustain repeated contractions or to continue to apply force against an external resistance over time.
4. Flexibility: The range of motion possible at a joint.
5. Body composition: The proportion of fat-free mass (muscle, bone, and organs) to fat mass in the body.

Being physically fit can help reduce the risk of chronic diseases such as heart disease, diabetes, and some types of cancer. It can also improve mental health, increase energy levels, and enhance overall quality of life.

Orthostatic hypotension is a type of low blood pressure that occurs when you stand up from a sitting or lying position. The drop in blood pressure causes a brief period of lightheadedness or dizziness, and can even cause fainting in some cases. This condition is also known as postural hypotension.

Orthostatic hypotension is caused by a rapid decrease in blood pressure when you stand up, which reduces the amount of blood that reaches your brain. Normally, when you stand up, your body compensates for this by increasing your heart rate and constricting blood vessels to maintain blood pressure. However, if these mechanisms fail or are impaired, orthostatic hypotension can occur.

Orthostatic hypotension is more common in older adults, but it can also affect younger people who have certain medical conditions or take certain medications. Some of the risk factors for orthostatic hypotension include dehydration, prolonged bed rest, pregnancy, diabetes, heart disease, Parkinson's disease, and certain neurological disorders.

If you experience symptoms of orthostatic hypotension, it is important to seek medical attention. Your healthcare provider can perform tests to determine the underlying cause of your symptoms and recommend appropriate treatment options. Treatment may include lifestyle changes, such as increasing fluid intake, avoiding alcohol and caffeine, and gradually changing positions from lying down or sitting to standing up. In some cases, medication may be necessary to manage orthostatic hypotension.

Retrospective studies, also known as retrospective research or looking back studies, are a type of observational study that examines data from the past to draw conclusions about possible causal relationships between risk factors and outcomes. In these studies, researchers analyze existing records, medical charts, or previously collected data to test a hypothesis or answer a specific research question.

Retrospective studies can be useful for generating hypotheses and identifying trends, but they have limitations compared to prospective studies, which follow participants forward in time from exposure to outcome. Retrospective studies are subject to biases such as recall bias, selection bias, and information bias, which can affect the validity of the results. Therefore, retrospective studies should be interpreted with caution and used primarily to generate hypotheses for further testing in prospective studies.

Muscarinic antagonists, also known as muscarinic receptor antagonists or parasympatholytics, are a class of drugs that block the action of acetylcholine at muscarinic receptors. Acetylcholine is a neurotransmitter that plays an important role in the parasympathetic nervous system, which helps to regulate various bodily functions such as heart rate, digestion, and respiration.

Muscarinic antagonists work by binding to muscarinic receptors, which are found in various organs throughout the body, including the eyes, lungs, heart, and gastrointestinal tract. By blocking the action of acetylcholine at these receptors, muscarinic antagonists can produce a range of effects depending on the specific receptor subtype that is affected.

For example, muscarinic antagonists may be used to treat conditions such as chronic obstructive pulmonary disease (COPD) and asthma by relaxing the smooth muscle in the airways and reducing bronchoconstriction. They may also be used to treat conditions such as urinary incontinence or overactive bladder by reducing bladder contractions.

Some common muscarinic antagonists include atropine, scopolamine, ipratropium, and tiotropium. It's important to note that these drugs can have significant side effects, including dry mouth, blurred vision, constipation, and confusion, especially when used in high doses or for prolonged periods of time.

Ganglionic blockers are a type of medication that blocks the activity of the ganglia, which are clusters of nerve cells located outside the central nervous system. These medications work by blocking the transmission of nerve impulses between the ganglia and the effector organs they innervate, such as muscles or glands.

Ganglionic blockers were once used in the treatment of various conditions, including hypertension (high blood pressure), peptic ulcers, and certain types of pain. However, their use has largely been abandoned due to their significant side effects, which can include dry mouth, blurred vision, constipation, difficulty urinating, and dizziness or lightheadedness upon standing.

There are two main types of ganglionic blockers: nicotinic and muscarinic. Nicotinic ganglionic blockers block the action of acetylcholine at nicotinic receptors in the ganglia, while muscarinic ganglionic blockers block the action of acetylcholine at muscarinic receptors in the ganglia.

Examples of ganglionic blockers include trimethaphan, hexamethonium, and pentolinium. These medications are typically administered intravenously in a hospital setting due to their short duration of action and potential for serious side effects.

"Random allocation," also known as "random assignment" or "randomization," is a process used in clinical trials and other research studies to distribute participants into different intervention groups (such as experimental group vs. control group) in a way that minimizes selection bias and ensures the groups are comparable at the start of the study.

In random allocation, each participant has an equal chance of being assigned to any group, and the assignment is typically made using a computer-generated randomization schedule or other objective methods. This process helps to ensure that any differences between the groups are due to the intervention being tested rather than pre-existing differences in the participants' characteristics.

A heart septal defect is a type of congenital heart defect, which means it is present at birth. It involves an abnormal opening in the septum, the wall that separates the two sides of the heart. This opening allows oxygen-rich blood to leak into the oxygen-poor blood chambers in the heart.

There are several types of heart septal defects, including:

1. Atrial Septal Defect (ASD): A hole in the atrial septum, the wall between the two upper chambers of the heart (the right and left atria).
2. Ventricular Septal Defect (VSD): A hole in the ventricular septum, the wall between the two lower chambers of the heart (the right and left ventricles).
3. Atrioventricular Septal Defect (AVSD): A combination of an ASD and a VSD, often accompanied by malformation of the mitral and/or tricuspid valves.

The severity of a heart septal defect depends on the size of the opening and its location in the septum. Small defects may cause no symptoms and may close on their own over time. Larger defects can lead to complications, such as heart failure, pulmonary hypertension, or infective endocarditis, and may require medical or surgical intervention.

Hypoplastic Left Heart Syndrome (HLHS) is a congenital heart defect in which the left side of the heart is underdeveloped. This includes the mitral valve, left ventricle, aortic valve, and aorta. The left ventricle is too small or absent, and the aorta is narrowed or poorly formed. As a result, blood cannot be adequately pumped to the body. Oxygen-rich blood from the lungs mixes with oxygen-poor blood in the heart, and the body does not receive enough oxygen-rich blood. HLHS is a serious condition that requires immediate medical attention and often surgical intervention.

"Sex factors" is a term used in medicine and epidemiology to refer to the differences in disease incidence, prevalence, or response to treatment that are observed between males and females. These differences can be attributed to biological differences such as genetics, hormones, and anatomy, as well as social and cultural factors related to gender.

For example, some conditions such as autoimmune diseases, depression, and osteoporosis are more common in women, while others such as cardiovascular disease and certain types of cancer are more prevalent in men. Additionally, sex differences have been observed in the effectiveness and side effects of various medications and treatments.

It is important to consider sex factors in medical research and clinical practice to ensure that patients receive appropriate and effective care.

Pracitolol is not a medical condition, it's a medication. Practolol is a beta blocker drug that is primarily used to treat various cardiovascular conditions such as hypertension (high blood pressure), angina (chest pain due to reduced blood flow to the heart), and certain types of arrhythmias (irregular heart rhythms).

Beta blockers like practolol work by blocking the effects of certain hormones, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart rate, lower blood pressure, and decrease the force of heart contractions, which can improve overall cardiovascular function and reduce the risk of heart-related complications.

It's important to note that practolol is not commonly used in clinical practice due to its association with a rare but serious side effect known as the "practolol syndrome." This condition can cause various symptoms such as dry eyes, skin rashes, and abnormalities of the thyroid gland. As a result, other beta blockers are generally preferred over practolol for the treatment of cardiovascular conditions.

The anaerobic threshold (also known as the lactate threshold or anaerobic threshold) is a medical and exercise term that refers to the maximum intensity of exercise that can be sustained without an excessive buildup of lactic acid in the blood. It is the point at which oxygen consumption reaches a steady state and cannot increase any further, despite an increase in exercise intensity. At this point, the body begins to rely more heavily on anaerobic metabolism, which produces energy quickly but also leads to the production of lactic acid. This threshold is often used as a measure of cardiovascular fitness and can be improved through training.

Heart neoplasms are abnormal growths or tumors that develop within the heart tissue. They can be benign (noncancerous) or malignant (cancerous). Benign tumors, such as myxomas and rhabdomyomas, are typically slower growing and less likely to spread, but they can still cause serious complications if they obstruct blood flow or damage heart valves. Malignant tumors, such as angiosarcomas and rhabdomyosarcomas, are fast-growing and have a higher risk of spreading to other parts of the body. Symptoms of heart neoplasms can include shortness of breath, chest pain, fatigue, and irregular heart rhythms. Treatment options depend on the type, size, and location of the tumor, and may include surgery, radiation therapy, or chemotherapy.

Galvanic Skin Response (GSR), also known as Electrodermal Activity (EDA), is a physiological response that reflects the activation of the sympathetic nervous system. It measures changes in the electrical properties of the skin, which are influenced by the sweat gland activity. GSR is often used as an indicator of emotional arousal or psychological stress in various research and clinical settings.

Ventricular dysfunction is a term that refers to the impaired ability of the ventricles, which are the lower chambers of the heart, to fill with blood or pump it efficiently to the rest of the body. This condition can lead to reduced cardiac output and may cause symptoms such as shortness of breath, fatigue, and fluid retention.

There are two types of ventricular dysfunction:

1. Systolic dysfunction: This occurs when the ventricles cannot contract forcefully enough to eject an adequate amount of blood out of the heart during each beat. This is often due to damage to the heart muscle, such as that caused by a heart attack or cardiomyopathy.
2. Diastolic dysfunction: This happens when the ventricles are unable to relax and fill properly with blood between beats. This can be caused by stiffening of the heart muscle, often due to aging, high blood pressure, or diabetes.

Both types of ventricular dysfunction can lead to heart failure, a serious condition in which the heart is unable to pump blood effectively to meet the body's needs. Treatment for ventricular dysfunction may include medications, lifestyle changes, and in some cases, medical procedures or surgery.

Lactic acid, also known as 2-hydroxypropanoic acid, is a chemical compound that plays a significant role in various biological processes. In the context of medicine and biochemistry, lactic acid is primarily discussed in relation to muscle metabolism and cellular energy production. Here's a medical definition for lactic acid:

Lactic acid (LA): A carboxylic acid with the molecular formula C3H6O3 that plays a crucial role in anaerobic respiration, particularly during strenuous exercise or conditions of reduced oxygen availability. It is formed through the conversion of pyruvate, catalyzed by the enzyme lactate dehydrogenase (LDH), when there is insufficient oxygen to complete the final step of cellular respiration in the Krebs cycle. The accumulation of lactic acid can lead to acidosis and muscle fatigue. Additionally, lactic acid serves as a vital intermediary in various metabolic pathways and is involved in the production of glucose through gluconeogenesis in the liver.

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls that can withstand the high pressure of blood being pumped out of the heart. Arteries branch off into smaller vessels called arterioles, which further divide into a vast network of tiny capillaries where the exchange of oxygen, nutrients, and waste occurs between the blood and the body's cells. After passing through the capillary network, deoxygenated blood collects in venules, then merges into veins, which return the blood back to the heart.

Carbazoles are aromatic organic compounds that consist of a tricyclic structure with two benzene rings fused to a five-membered ring containing two nitrogen atoms. The chemical formula for carbazole is C12H9N. Carbazoles are found in various natural sources, including coal tar and certain plants. They also have various industrial applications, such as in the production of dyes, pigments, and pharmaceuticals. In a medical context, carbazoles are not typically referred to as a single entity but rather as a class of compounds with potential therapeutic activity. Some carbazole derivatives have been studied for their anti-cancer, anti-inflammatory, and anti-microbial properties.

I couldn't find a specific medical definition for "running" as an exercise or physical activity. However, in a medical or clinical context, running usually refers to the act of moving at a steady speed by lifting and setting down each foot in turn, allowing for a faster motion than walking. It is often used as a form of exercise, recreation, or transportation.

Running can be described medically in terms of its biomechanics, physiological effects, and potential health benefits or risks. For instance, running involves the repetitive movement of the lower extremities, which can lead to increased heart rate, respiratory rate, and metabolic demand, ultimately improving cardiovascular fitness and burning calories. However, it is also associated with potential injuries such as runner's knee, shin splints, or plantar fasciitis, especially if proper precautions are not taken.

It is important to note that before starting any new exercise regimen, including running, individuals should consult their healthcare provider, particularly those with pre-existing medical conditions or concerns about their ability to engage in physical activity safely.

Adrenergic alpha-agonists are a type of medication that binds to and activates adrenergic alpha receptors, which are found in the nervous system and other tissues throughout the body. These receptors are activated naturally by chemicals called catecholamines, such as norepinephrine and epinephrine (also known as adrenaline), that are released in response to stress or excitement.

When adrenergic alpha-agonists bind to these receptors, they mimic the effects of catecholamines and cause various physiological responses, such as vasoconstriction (constriction of blood vessels), increased heart rate and force of heart contractions, and relaxation of smooth muscle in the airways.

Adrenergic alpha-agonists are used to treat a variety of medical conditions, including hypertension (high blood pressure), glaucoma, nasal congestion, and attention deficit hyperactivity disorder (ADHD). Examples of adrenergic alpha-agonists include phenylephrine, clonidine, and guanfacine.

It's important to note that adrenergic alpha-agonists can have both beneficial and harmful effects, depending on the specific medication, dosage, and individual patient factors. Therefore, they should only be used under the guidance of a healthcare professional.

Cardiac catheterization is a medical procedure used to diagnose and treat cardiovascular conditions. In this procedure, a thin, flexible tube called a catheter is inserted into a blood vessel in the arm or leg and threaded up to the heart. The catheter can be used to perform various diagnostic tests, such as measuring the pressure inside the heart chambers and assessing the function of the heart valves.

Cardiac catheterization can also be used to treat certain cardiovascular conditions, such as narrowed or blocked arteries. In these cases, a balloon or stent may be inserted through the catheter to open up the blood vessel and improve blood flow. This procedure is known as angioplasty or percutaneous coronary intervention (PCI).

Cardiac catheterization is typically performed in a hospital cardiac catheterization laboratory by a team of healthcare professionals, including cardiologists, radiologists, and nurses. The procedure may be done under local anesthesia with sedation or general anesthesia, depending on the individual patient's needs and preferences.

Overall, cardiac catheterization is a valuable tool in the diagnosis and treatment of various heart conditions, and it can help improve symptoms, reduce complications, and prolong life for many patients.

In medical terms, "immersion" is not a term with a specific clinical definition. However, in general terms, immersion refers to the act of placing something or someone into a liquid or environment completely. In some contexts, it may be used to describe a type of wound care where the wound is covered completely with a medicated dressing or solution. It can also be used to describe certain medical procedures or therapies that involve submerging a part of the body in a liquid, such as hydrotherapy.

WKY (Wistar Kyoto) is not a term that refers to "rats, inbred" in a medical definition. Instead, it is a strain of laboratory rat that is widely used in biomedical research. WKY rats are an inbred strain, which means they are the result of many generations of brother-sister matings, resulting in a genetically uniform population.

WKY rats originated from the Wistar Institute in Philadelphia and were established as a normotensive control strain to contrast with other rat strains that exhibit hypertension. They have since been used in various research areas, including cardiovascular, neurological, and behavioral studies. Compared to other commonly used rat strains like the spontaneously hypertensive rat (SHR), WKY rats are known for their lower blood pressure, reduced stress response, and greater emotionality.

In summary, "WKY" is a designation for an inbred strain of laboratory rat that is often used as a control group in biomedical research due to its normotensive characteristics.

A Severity of Illness Index is a measurement tool used in healthcare to assess the severity of a patient's condition and the risk of mortality or other adverse outcomes. These indices typically take into account various physiological and clinical variables, such as vital signs, laboratory values, and co-morbidities, to generate a score that reflects the patient's overall illness severity.

Examples of Severity of Illness Indices include the Acute Physiology and Chronic Health Evaluation (APACHE) system, the Simplified Acute Physiology Score (SAPS), and the Mortality Probability Model (MPM). These indices are often used in critical care settings to guide clinical decision-making, inform prognosis, and compare outcomes across different patient populations.

It is important to note that while these indices can provide valuable information about a patient's condition, they should not be used as the sole basis for clinical decision-making. Rather, they should be considered in conjunction with other factors, such as the patient's overall clinical presentation, treatment preferences, and goals of care.

Electric stimulation, also known as electrical nerve stimulation or neuromuscular electrical stimulation, is a therapeutic treatment that uses low-voltage electrical currents to stimulate nerves and muscles. It is often used to help manage pain, promote healing, and improve muscle strength and mobility. The electrical impulses can be delivered through electrodes placed on the skin or directly implanted into the body.

In a medical context, electric stimulation may be used for various purposes such as:

1. Pain management: Electric stimulation can help to block pain signals from reaching the brain and promote the release of endorphins, which are natural painkillers produced by the body.
2. Muscle rehabilitation: Electric stimulation can help to strengthen muscles that have become weak due to injury, illness, or surgery. It can also help to prevent muscle atrophy and improve range of motion.
3. Wound healing: Electric stimulation can promote tissue growth and help to speed up the healing process in wounds, ulcers, and other types of injuries.
4. Urinary incontinence: Electric stimulation can be used to strengthen the muscles that control urination and reduce symptoms of urinary incontinence.
5. Migraine prevention: Electric stimulation can be used as a preventive treatment for migraines by applying electrical impulses to specific nerves in the head and neck.

It is important to note that electric stimulation should only be administered under the guidance of a qualified healthcare professional, as improper use can cause harm or discomfort.

Cardiac volume refers to the amount of blood contained within the heart chambers at any given point in time. It is a measure of the volume of blood that is being moved by the heart during each cardiac cycle, which includes both systole (contraction) and diastole (relaxation) phases.

There are several types of cardiac volumes that are commonly measured or estimated using medical imaging techniques such as echocardiography or cardiac magnetic resonance imaging (MRI). These include:

1. End-diastolic volume (EDV): This is the volume of blood in the heart chambers at the end of diastole, when the heart chambers are fully filled with blood.
2. End-systolic volume (ESV): This is the volume of blood in the heart chambers at the end of systole, when the heart chambers have contracted and ejected most of the blood.
3. Stroke volume (SV): This is the difference between the EDV and ESV, and represents the amount of blood that is pumped out of the heart with each beat.
4. Cardiac output (CO): This is the product of the stroke volume and heart rate, and represents the total amount of blood that is pumped by the heart in one minute.

Abnormalities in cardiac volumes can indicate various heart conditions such as heart failure, valvular heart disease, or cardiomyopathy.

Adenosine is a purine nucleoside that is composed of a sugar (ribose) and the base adenine. It plays several important roles in the body, including serving as a precursor for the synthesis of other molecules such as ATP, NAD+, and RNA.

In the medical context, adenosine is perhaps best known for its use as a pharmaceutical agent to treat certain cardiac arrhythmias. When administered intravenously, it can help restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT) by slowing conduction through the atrioventricular node and interrupting the reentry circuit responsible for the arrhythmia.

Adenosine can also be used as a diagnostic tool to help differentiate between narrow-complex tachycardias of supraventricular origin and those that originate from below the ventricles (such as ventricular tachycardia). This is because adenosine will typically terminate PSVT but not affect the rhythm of VT.

It's worth noting that adenosine has a very short half-life, lasting only a few seconds in the bloodstream. This means that its effects are rapidly reversible and generally well-tolerated, although some patients may experience transient symptoms such as flushing, chest pain, or shortness of breath.

Ventricular pressure refers to the pressure within the ventricles, which are the lower chambers of the heart. In the left ventricle, the pressure measures the force that the blood exerts on the walls as it is pumped out to the rest of the body. In the right ventricle, the pressure measures the force of the blood being pumped into the pulmonary artery and ultimately to the lungs for oxygenation.

Normally, the left ventricular pressure ranges from 8-12 mmHg at rest when the heart is relaxed (diastolic pressure) and can increase up to 120-140 mmHg during contraction (systolic pressure). The right ventricular pressure is lower than the left, with a normal diastolic pressure of 0-6 mmHg and a systolic pressure ranging from 15-30 mmHg.

Abnormal ventricular pressures can indicate various heart conditions, such as heart failure, hypertension, or valvular heart disease. Regular monitoring of ventricular pressure is essential in managing these conditions and ensuring proper heart function.

In a medical or physiological context, "arousal" refers to the state of being awake and responsive to stimuli. It involves the activation of the nervous system, particularly the autonomic nervous system, which prepares the body for action. Arousal levels can vary from low (such as during sleep) to high (such as during states of excitement or stress). In clinical settings, changes in arousal may be assessed to help diagnose conditions such as coma, brain injury, or sleep disorders. It is also used in the context of sexual response, where it refers to the level of physical and mental awareness and readiness for sexual activity.

Body temperature regulation, also known as thermoregulation, is the process by which the body maintains its core internal temperature within a narrow range, despite varying external temperatures. This is primarily controlled by the hypothalamus in the brain, which acts as a thermostat and receives input from temperature receptors throughout the body. When the body's temperature rises above or falls below the set point, the hypothalamus initiates responses to bring the temperature back into balance. These responses can include shivering to generate heat, sweating to cool down, vasodilation or vasoconstriction of blood vessels to regulate heat loss, and changes in metabolic rate. Effective body temperature regulation is crucial for maintaining optimal physiological function and overall health.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Angina pectoris is a medical term that describes chest pain or discomfort caused by an inadequate supply of oxygen-rich blood to the heart muscle. This condition often occurs due to coronary artery disease, where the coronary arteries become narrowed or blocked by the buildup of cholesterol, fatty deposits, and other substances, known as plaques. These blockages can reduce blood flow to the heart, causing ischemia (lack of oxygen) and leading to angina symptoms.

There are two primary types of angina: stable and unstable. Stable angina is predictable and usually occurs during physical exertion or emotional stress when the heart needs more oxygen-rich blood. The pain typically subsides with rest or after taking prescribed nitroglycerin medication, which helps widen the blood vessels and improve blood flow to the heart.

Unstable angina, on the other hand, is more severe and unpredictable. It can occur at rest, during sleep, or with minimal physical activity and may not be relieved by rest or nitroglycerin. Unstable angina is considered a medical emergency, as it could indicate an imminent heart attack.

Symptoms of angina pectoris include chest pain, pressure, tightness, or heaviness that typically radiates to the left arm, neck, jaw, or back. Shortness of breath, nausea, sweating, and fatigue may also accompany angina symptoms. Immediate medical attention is necessary if you experience chest pain or discomfort, especially if it's new, severe, or persistent, as it could be a sign of a more serious condition like a heart attack.

A single-blind method in medical research is a study design where the participants are unaware of the group or intervention they have been assigned to, but the researchers conducting the study know which participant belongs to which group. This is done to prevent bias from the participants' expectations or knowledge of their assignment, while still allowing the researchers to control the study conditions and collect data.

In a single-blind trial, the participants do not know whether they are receiving the active treatment or a placebo (a sham treatment that looks like the real thing but has no therapeutic effect), whereas the researcher knows which participant is receiving which intervention. This design helps to ensure that the participants' responses and outcomes are not influenced by their knowledge of the treatment assignment, while still allowing the researchers to assess the effectiveness or safety of the intervention being studied.

Single-blind methods are commonly used in clinical trials and other medical research studies where it is important to minimize bias and control for confounding variables that could affect the study results.

The endocardium is the innermost layer of tissue that lines the chambers of the heart and the valves between them. It is a thin, smooth membrane that is in contact with the blood within the heart. This layer helps to maintain the heart's internal environment, facilitates the smooth movement of blood through the heart, and provides a protective barrier against infection and other harmful substances. The endocardium is composed of simple squamous epithelial cells called endothelial cells, which are supported by a thin layer of connective tissue.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Angiotensin II is a potent vasoactive peptide hormone that plays a critical role in the renin-angiotensin-aldosterone system (RAAS), which is a crucial regulator of blood pressure and fluid balance in the body. It is formed from angiotensin I through the action of an enzyme called angiotensin-converting enzyme (ACE).

Angiotensin II has several physiological effects on various organs, including:

1. Vasoconstriction: Angiotensin II causes contraction of vascular smooth muscle, leading to an increase in peripheral vascular resistance and blood pressure.
2. Aldosterone release: Angiotensin II stimulates the adrenal glands to release aldosterone, a hormone that promotes sodium reabsorption and potassium excretion in the kidneys, thereby increasing water retention and blood volume.
3. Sympathetic nervous system activation: Angiotensin II activates the sympathetic nervous system, leading to increased heart rate and contractility, further contributing to an increase in blood pressure.
4. Thirst regulation: Angiotensin II stimulates the hypothalamus to increase thirst, promoting water intake and helping to maintain intravascular volume.
5. Cell growth and fibrosis: Angiotensin II has been implicated in various pathological processes, such as cell growth, proliferation, and fibrosis, which can contribute to the development of cardiovascular and renal diseases.

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are two classes of medications commonly used in clinical practice to target the RAAS by blocking the formation or action of angiotensin II, respectively. These drugs have been shown to be effective in managing hypertension, heart failure, and chronic kidney disease.

Exercise tolerance is a term used to describe the ability of an individual to perform physical activity or exercise without experiencing symptoms such as shortness of breath, chest pain, or undue fatigue. It is often used as a measure of cardiovascular fitness and can be assessed through various tests, such as a stress test or a six-minute walk test. Exercise intolerance may indicate the presence of underlying medical conditions, such as heart disease, lung disease, or deconditioning.

Labetalol is an antihypertensive drug, which is a type of medication used to treat high blood pressure. It is classified as a non-selective beta blocker and selective alpha-1 receptor blocker. This means that it works by blocking the effects of certain hormones on the heart and blood vessels, leading to a decrease in heart rate and relaxation of the blood vessels, thereby reducing blood pressure.

Labetalol is available in oral (tablet) and injectable forms. It may be used alone or in combination with other medications to treat high blood pressure. Common side effects of labetalol include dizziness, lightheadedness, and fatigue. As with any medication, it should be taken under the supervision of a healthcare provider, who will consider the patient's medical history, current medications, and other factors before prescribing it.

Chemoreceptor cells are specialized sensory neurons that detect and respond to chemical changes in the internal or external environment. They play a crucial role in maintaining homeostasis within the body by converting chemical signals into electrical impulses, which are then transmitted to the central nervous system for further processing and response.

There are two main types of chemoreceptor cells:

1. Oxygen Chemoreceptors: These cells are located in the carotid bodies near the bifurcation of the common carotid artery and in the aortic bodies close to the aortic arch. They monitor the levels of oxygen, carbon dioxide, and pH in the blood and respond to decreases in oxygen concentration or increases in carbon dioxide and hydrogen ions (indicating acidity) by increasing their firing rate. This signals the brain to increase respiratory rate and depth, thereby restoring normal oxygen levels.

2. Taste Cells: These chemoreceptor cells are found within the taste buds of the tongue and other areas of the oral cavity. They detect specific tastes (salty, sour, sweet, bitter, and umami) by interacting with molecules from food. When a tastant binds to receptors on the surface of a taste cell, it triggers a series of intracellular signaling events that ultimately lead to the generation of an action potential. This information is then relayed to the brain, where it is interpreted as taste sensation.

In summary, chemoreceptor cells are essential for maintaining physiological balance by detecting and responding to chemical stimuli in the body. They play a critical role in regulating vital functions such as respiration and digestion.

Isoflurane is a volatile halogenated ether used for induction and maintenance of general anesthesia. It is a colorless liquid with a pungent, sweet odor. Isoflurane is an agonist at the gamma-aminobutyric acid type A (GABAA) receptor and inhibits excitatory neurotransmission in the brain, leading to unconsciousness and immobility. It has a rapid onset and offset of action due to its low blood solubility, allowing for quick adjustments in anesthetic depth during surgery. Isoflurane is also known for its bronchodilator effects, making it useful in patients with reactive airway disease. However, it can cause dose-dependent decreases in heart rate and blood pressure, so careful hemodynamic monitoring is required during its use.

Apnea is a medical condition defined as the cessation of breathing for 10 seconds or more. It can occur during sleep (sleep apnea) or while awake (wakeful apnea). There are different types of sleep apnea, including obstructive sleep apnea, central sleep apnea, and complex sleep apnea syndrome. Obstructive sleep apnea occurs when the airway becomes blocked during sleep, while central sleep apnea occurs when the brain fails to signal the muscles to breathe. Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, is a combination of obstructive and central sleep apneas. Sleep apnea can lead to various complications, such as fatigue, difficulty concentrating, high blood pressure, heart disease, and stroke.

Pindolol is a non-selective beta blocker that is used in the treatment of hypertension (high blood pressure) and certain types of arrhythmias (irregular heart rhythms). It works by blocking the action of certain hormones such as adrenaline and noradrenaline on the heart, which helps to reduce the heart rate, contractility, and conduction velocity, leading to a decrease in blood pressure.

Pindolol is also a partial agonist at beta-2 receptors, which means that it can stimulate these receptors to some extent, reducing the likelihood of bronchospasm (a side effect seen with other non-selective beta blockers). However, pindolol may still cause bronchospasm in patients with a history of asthma or chronic obstructive pulmonary disease (COPD), so it should be used with caution in these populations.

Pindolol is available in immediate-release and extended-release formulations, and the dosage is typically individualized based on the patient's response to therapy. Common side effects of pindolol include dizziness, fatigue, and gastrointestinal symptoms such as nausea and diarrhea.

Sudden death is a term used to describe a situation where a person dies abruptly and unexpectedly, often within minutes to hours of the onset of symptoms. It is typically caused by cardiac or respiratory arrest, which can be brought on by various medical conditions such as heart disease, stroke, severe infections, drug overdose, or trauma. In some cases, the exact cause of sudden death may remain unknown even after a thorough post-mortem examination.

It is important to note that sudden death should not be confused with "sudden cardiac death," which specifically refers to deaths caused by the abrupt loss of heart function (cardiac arrest). Sudden cardiac death is often related to underlying heart conditions such as coronary artery disease, cardiomyopathy, or electrical abnormalities in the heart.

Long QT syndrome (LQTS) is a cardiac electrical disorder characterized by a prolonged QT interval on the electrocardiogram (ECG), which can potentially trigger rapid, chaotic heartbeats known as ventricular tachyarrhythmias, such as torsades de pointes. These arrhythmias can be life-threatening and lead to syncope (fainting) or sudden cardiac death. LQTS is often congenital but may also be acquired due to certain medications, medical conditions, or electrolyte imbalances. It's essential to identify and manage LQTS promptly to reduce the risk of severe complications.

Glycopyrrolate is an anticholinergic medication that works by blocking the action of acetylcholine, a chemical messenger in the body. It reduces the secretions of certain organs and is used to treat various conditions such as peptic ulcers, reducing saliva production during surgical procedures, preventing motion sickness, and managing some symptoms of Parkinson's disease.

In medical terms, glycopyrrolate is a competitive antagonist of muscarinic acetylcholine receptors. It has a particular affinity for the M1, M2, and M3 receptor subtypes. By blocking these receptors, it inhibits the parasympathetic nervous system's effects on various organs, leading to decreased glandular secretions (such as saliva, sweat, and gastric acid), slowed heart rate, and relaxation of smooth muscles in the digestive tract and bronchioles.

Glycopyrrolate is available in oral, intravenous, and topical forms and should be used under the supervision of a healthcare professional due to its potential side effects, including dry mouth, blurred vision, dizziness, drowsiness, and urinary retention.

Pulmonary gas exchange is the process by which oxygen (O2) from inhaled air is transferred to the blood, and carbon dioxide (CO2), a waste product of metabolism, is removed from the blood and exhaled. This process occurs in the lungs, primarily in the alveoli, where the thin walls of the alveoli and capillaries allow for the rapid diffusion of gases between them. The partial pressure gradient between the alveolar air and the blood in the pulmonary capillaries drives this diffusion process. Oxygen-rich blood is then transported to the body's tissues, while CO2-rich blood returns to the lungs to be exhaled.

Ventricular function, in the context of cardiac medicine, refers to the ability of the heart's ventricles (the lower chambers) to fill with blood during the diastole phase and eject blood during the systole phase. The ventricles are primarily responsible for pumping oxygenated blood out to the body (left ventricle) and deoxygenated blood to the lungs (right ventricle).

There are several ways to assess ventricular function, including:

1. Ejection Fraction (EF): This is the most commonly used measure of ventricular function. It represents the percentage of blood that is ejected from the ventricle during each heartbeat. A normal left ventricular ejection fraction is typically between 55% and 70%.
2. Fractional Shortening (FS): This is another measure of ventricular function, which calculates the change in size of the ventricle during contraction as a percentage of the original size. A normal FS for the left ventricle is typically between 25% and 45%.
3. Stroke Volume (SV): This refers to the amount of blood that is pumped out of the ventricle with each heartbeat. SV is calculated by multiplying the ejection fraction by the end-diastolic volume (the amount of blood in the ventricle at the end of diastole).
4. Cardiac Output (CO): This is the total amount of blood that the heart pumps in one minute. It is calculated by multiplying the stroke volume by the heart rate.

Impaired ventricular function can lead to various cardiovascular conditions, such as heart failure, cardiomyopathy, and valvular heart disease. Assessing ventricular function is crucial for diagnosing these conditions, monitoring treatment response, and guiding clinical decision-making.

Inhalational anesthesia is a type of general anesthesia that is induced by the inhalation of gases or vapors. It is administered through a breathing system, which delivers the anesthetic agents to the patient via a face mask, laryngeal mask airway, or endotracheal tube.

The most commonly used inhalational anesthetics include nitrous oxide, sevoflurane, isoflurane, and desflurane. These agents work by depressing the central nervous system, causing a reversible loss of consciousness, amnesia, analgesia, and muscle relaxation.

The depth of anesthesia can be easily adjusted during the procedure by changing the concentration of the anesthetic agent. Once the procedure is complete, the anesthetic agents are eliminated from the body through exhalation, allowing for a rapid recovery.

Inhalational anesthesia is commonly used in a wide range of surgical procedures due to its ease of administration, quick onset and offset of action, and ability to rapidly adjust the depth of anesthesia. However, it requires careful monitoring and management by trained anesthesia providers to ensure patient safety and optimize outcomes.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Myocardial reperfusion is the restoration of blood flow to the heart muscle (myocardium), usually after a period of ischemia or reduced oxygen supply, such as during a myocardial infarction (heart attack). This can be achieved through various medical interventions, including thrombolytic therapy, percutaneous coronary intervention (PCI), or coronary artery bypass surgery (CABG). The goal of myocardial reperfusion is to salvage the jeopardized myocardium, preserve cardiac function, and reduce the risk of complications like heart failure or arrhythmias. However, it's important to note that while reperfusion is crucial for treating ischemic heart disease, it can also lead to additional injury to the heart muscle, known as reperfusion injury.

Pulmonary wedge pressure, also known as pulmonary capillary wedge pressure (PCWP) or left heart filling pressure, is a measurement obtained during right heart catheterization. It reflects the pressure in the left atrium, which is an estimate of the diastolic pressure in the left ventricle. Normal PCWP ranges from 4 to 12 mmHg. Increased pulmonary wedge pressure can indicate heart failure or other cardiac disorders that affect the left side of the heart.

Bicycling is defined in medical terms as the act of riding a bicycle. It involves the use of a two-wheeled vehicle that is propelled by pedaling, with the power being transferred to the rear wheel through a chain and sprocket system. Bicycling can be done for various purposes such as transportation, recreation, exercise, or sport.

Regular bicycling has been shown to have numerous health benefits, including improving cardiovascular fitness, increasing muscle strength and flexibility, reducing stress and anxiety, and helping with weight management. However, it is important to wear a helmet while bicycling to reduce the risk of head injury in case of an accident. Additionally, cyclists should follow traffic rules and be aware of their surroundings to ensure their safety and the safety of others on the road.

Nonparametric statistics is a branch of statistics that does not rely on assumptions about the distribution of variables in the population from which the sample is drawn. In contrast to parametric methods, nonparametric techniques make fewer assumptions about the data and are therefore more flexible in their application. Nonparametric tests are often used when the data do not meet the assumptions required for parametric tests, such as normality or equal variances.

Nonparametric statistical methods include tests such as the Wilcoxon rank-sum test (also known as the Mann-Whitney U test) for comparing two independent groups, the Wilcoxon signed-rank test for comparing two related groups, and the Kruskal-Wallis test for comparing more than two independent groups. These tests use the ranks of the data rather than the actual values to make comparisons, which allows them to be used with ordinal or continuous data that do not meet the assumptions of parametric tests.

Overall, nonparametric statistics provide a useful set of tools for analyzing data in situations where the assumptions of parametric methods are not met, and can help researchers draw valid conclusions from their data even when the data are not normally distributed or have other characteristics that violate the assumptions of parametric tests.

Proportional hazards models are a type of statistical analysis used in medical research to investigate the relationship between covariates (predictor variables) and survival times. The most common application of proportional hazards models is in the Cox regression model, which is named after its developer, Sir David Cox.

In a proportional hazards model, the hazard rate or risk of an event occurring at a given time is assumed to be proportional to the hazard rate of a reference group, after adjusting for the covariates. This means that the ratio of the hazard rates between any two individuals remains constant over time, regardless of their survival times.

Mathematically, the hazard function h(t) at time t for an individual with a set of covariates X can be expressed as:

h(t|X) = h0(t) \* exp(β1X1 + β2X2 + ... + βpXp)

where h0(t) is the baseline hazard function, X1, X2, ..., Xp are the covariates, and β1, β2, ..., βp are the regression coefficients that represent the effect of each covariate on the hazard rate.

The assumption of proportionality is crucial in the interpretation of the results from a Cox regression model. If the assumption is violated, then the estimated regression coefficients may be biased and misleading. Therefore, it is important to test for the proportional hazards assumption before interpreting the results of a Cox regression analysis.

The aorta is the largest artery in the human body, which originates from the left ventricle of the heart and carries oxygenated blood to the rest of the body. It can be divided into several parts, including the ascending aorta, aortic arch, and descending aorta. The ascending aorta gives rise to the coronary arteries that supply blood to the heart muscle. The aortic arch gives rise to the brachiocephalic, left common carotid, and left subclavian arteries, which supply blood to the head, neck, and upper extremities. The descending aorta travels through the thorax and abdomen, giving rise to various intercostal, visceral, and renal arteries that supply blood to the chest wall, organs, and kidneys.

I must clarify that the term "Guinea Pigs" is not typically used in medical definitions. However, in colloquial or informal language, it may refer to people who are used as the first to try out a new medical treatment or drug. This is known as being a "test subject" or "in a clinical trial."

In the field of scientific research, particularly in studies involving animals, guinea pigs are small rodents that are often used as experimental subjects due to their size, cost-effectiveness, and ease of handling. They are not actually pigs from Guinea, despite their name's origins being unclear. However, they do not exactly fit the description of being used in human medical experiments.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

The heart ventricles are the two lower chambers of the heart that receive blood from the atria and pump it to the lungs or the rest of the body. The right ventricle pumps deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body. Both ventricles have thick, muscular walls to generate the pressure necessary to pump blood through the circulatory system.

Syncope is a medical term defined as a transient, temporary loss of consciousness and postural tone due to reduced blood flow to the brain. It's often caused by a drop in blood pressure, which can be brought on by various factors such as dehydration, emotional stress, prolonged standing, or certain medical conditions like heart diseases, arrhythmias, or neurological disorders.

During a syncope episode, an individual may experience warning signs such as lightheadedness, dizziness, blurred vision, or nausea before losing consciousness. These episodes usually last only a few minutes and are followed by a rapid, full recovery. However, if left untreated or undiagnosed, recurrent syncope can lead to severe injuries from falls or even life-threatening conditions related to the underlying cause.

Central venous pressure (CVP) is the blood pressure measured in the large veins that enter the right atrium of the heart. It reflects the amount of blood returning to the heart and the ability of the heart to pump it effectively. CVP is used as an indicator of a person's intravascular volume status, cardiac function, and overall hemodynamic performance. The measurement is taken using a central venous catheter placed in a large vein such as the internal jugular or subclavian vein. Normal CVP values range from 0 to 8 mmHg (millimeters of mercury) in adults when measured at the level of the right atrium.

Physiological adaptation refers to the changes or modifications that occur in an organism's biological functions or structures as a result of environmental pressures or changes. These adaptations enable the organism to survive and reproduce more successfully in its environment. They can be short-term, such as the constriction of blood vessels in response to cold temperatures, or long-term, such as the evolution of longer limbs in animals that live in open environments.

In the context of human physiology, examples of physiological adaptation include:

1. Acclimatization: The process by which the body adjusts to changes in environmental conditions, such as altitude or temperature. For example, when a person moves to a high-altitude location, their body may produce more red blood cells to compensate for the lower oxygen levels, leading to improved oxygen delivery to tissues.

2. Exercise adaptation: Regular physical activity can lead to various physiological adaptations, such as increased muscle strength and endurance, enhanced cardiovascular function, and improved insulin sensitivity.

3. Hormonal adaptation: The body can adjust hormone levels in response to changes in the environment or internal conditions. For instance, during prolonged fasting, the body releases stress hormones like cortisol and adrenaline to help maintain energy levels and prevent muscle wasting.

4. Sensory adaptation: Our senses can adapt to different stimuli over time. For example, when we enter a dark room after being in bright sunlight, it takes some time for our eyes to adjust to the new light level. This process is known as dark adaptation.

5. Aging-related adaptations: As we age, various physiological changes occur that help us adapt to the changing environment and maintain homeostasis. These include changes in body composition, immune function, and cognitive abilities.

Cardiovascular physiological processes refer to the functioning and mechanisms of the heart and blood vessels to maintain adequate circulation of blood, oxygen, and nutrients throughout the body. This includes:

1. Heart rate and rhythm: The heart's ability to contract and relax regularly to pump blood.
2. Cardiac output: The amount of blood pumped by the heart in one minute, calculated as stroke volume (amount of blood pumped per beat) multiplied by heart rate.
3. Blood pressure: The force exerted by circulating blood on the walls of the blood vessels, determined by cardiac output and systemic vascular resistance.
4. Vascular tone: The degree of constriction or dilation of blood vessels, regulated by the autonomic nervous system and various hormones to maintain blood pressure and blood flow.
5. Blood flow distribution: The regulation of blood flow to different organs based on their metabolic demands, influenced by local autoregulation and neural and humoral factors.
6. Electrolyte and fluid balance: The maintenance of proper electrolyte concentrations and fluid volume in the blood and tissues, essential for cardiovascular function and overall homeostasis.
7. Cardiac and vascular response to stress: The adaptive changes in heart rate, contractility, vascular tone, and blood flow during exercise or other physiological stressors.
8. Hemostasis and thrombosis: The processes that maintain the integrity of the cardiovascular system by preventing excessive bleeding (hemostasis) while minimizing the risk of pathological clot formation (thrombosis).

Beta-1 adrenergic receptors (also known as β1-adrenergic receptors) are a type of G protein-coupled receptor found in the cell membrane. They are activated by the catecholamines, particularly noradrenaline (norepinephrine) and adrenaline (epinephrine), which are released by the sympathetic nervous system as part of the "fight or flight" response.

When a catecholamine binds to a β1-adrenergic receptor, it triggers a series of intracellular signaling events that ultimately lead to an increase in the rate and force of heart contractions, as well as an increase in renin secretion from the kidneys. These effects help to prepare the body for physical activity by increasing blood flow to the muscles and improving the efficiency of the cardiovascular system.

In addition to their role in the regulation of cardiovascular function, β1-adrenergic receptors have been implicated in a variety of physiological processes, including lipolysis (the breakdown of fat), glucose metabolism, and the regulation of mood and cognition.

Dysregulation of β1-adrenergic receptor signaling has been linked to several pathological conditions, including heart failure, hypertension, and anxiety disorders. As a result, β1-adrenergic receptors are an important target for the development of therapeutics used in the treatment of these conditions.

Sleep is a complex physiological process characterized by altered consciousness, relatively inhibited sensory activity, reduced voluntary muscle activity, and decreased interaction with the environment. It's typically associated with specific stages that can be identified through electroencephalography (EEG) patterns. These stages include rapid eye movement (REM) sleep, associated with dreaming, and non-rapid eye movement (NREM) sleep, which is further divided into three stages.

Sleep serves a variety of functions, including restoration and strengthening of the immune system, support for growth and development in children and adolescents, consolidation of memory, learning, and emotional regulation. The lack of sufficient sleep or poor quality sleep can lead to significant health problems, such as obesity, diabetes, cardiovascular disease, and even cognitive decline.

The American Academy of Sleep Medicine (AASM) defines sleep as "a period of daily recurring natural rest during which consciousness is suspended and metabolic processes are reduced." However, it's important to note that the exact mechanisms and purposes of sleep are still being researched and debated among scientists.

An animal model in medicine refers to the use of non-human animals in experiments to understand, predict, and test responses and effects of various biological and chemical interactions that may also occur in humans. These models are used when studying complex systems or processes that cannot be easily replicated or studied in human subjects, such as genetic manipulation or exposure to harmful substances. The choice of animal model depends on the specific research question being asked and the similarities between the animal's and human's biological and physiological responses. Examples of commonly used animal models include mice, rats, rabbits, guinea pigs, and non-human primates.

Ischemic preconditioning, myocardial is a phenomenon in cardiac physiology where the heart muscle (myocardium) is made more resistant to the damaging effects of a prolonged period of reduced blood flow (ischemia) or oxygen deprivation (hypoxia), followed by reperfusion (restoration of blood flow). This resistance is developed through a series of brief, controlled episodes of ischemia and reperfusion, which act as "preconditioning" stimuli, protecting the myocardium from subsequent more severe ischemic events. The adaptive responses triggered during preconditioning include the activation of various protective signaling pathways, release of protective factors, and modulation of cellular metabolism, ultimately leading to reduced infarct size, improved contractile function, and attenuated reperfusion injury in the myocardium.

Skin temperature is the measure of heat emitted by the skin, which can be an indicator of the body's core temperature. It is typically lower than the body's internal temperature and varies depending on factors such as environmental temperature, blood flow, and physical activity. Skin temperature is often used as a vital sign in medical settings and can be measured using various methods, including thermal scanners, digital thermometers, or mercury thermometers. Changes in skin temperature may also be associated with certain medical conditions, such as inflammation, infection, or nerve damage.

A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.

Phentolamine is a non-selective alpha-blocker drug, which means it blocks both alpha-1 and alpha-2 receptors. It works by relaxing the muscle around blood vessels, which increases blood flow and lowers blood pressure. Phentolamine is used medically for various purposes, including the treatment of high blood pressure, the diagnosis and treatment of pheochromocytoma (a tumor that releases hormones causing high blood pressure), and as an antidote to prevent severe hypertension caused by certain medications or substances. It may also be used in diagnostic tests to determine if a patient's blood pressure is reactive to drugs, and it can be used during some surgical procedures to help lower the risk of hypertensive crises.

Phentolamine is available in two forms: an injectable solution and oral tablets. The injectable form is typically administered by healthcare professionals in a clinical setting, while the oral tablets are less commonly used due to their short duration of action and potential for causing severe drops in blood pressure. As with any medication, phentolamine should be taken under the supervision of a healthcare provider, and patients should follow their doctor's instructions carefully to minimize the risk of side effects and ensure the drug's effectiveness.

Ventricular Tachycardia (VT) is a rapid heart rhythm that originates from the ventricles, the lower chambers of the heart. It is defined as three or more consecutive ventricular beats at a rate of 120 beats per minute or greater in a resting adult. This abnormal heart rhythm can cause the heart to pump less effectively, leading to inadequate blood flow to the body and potentially life-threatening conditions such as hypotension, shock, or cardiac arrest.

VT can be classified into three types based on its duration, hemodynamic stability, and response to treatment:

1. Non-sustained VT (NSVT): It lasts for less than 30 seconds and is usually well tolerated without causing significant symptoms or hemodynamic instability.
2. Sustained VT (SVT): It lasts for more than 30 seconds, causes symptoms such as palpitations, dizziness, shortness of breath, or chest pain, and may lead to hemodynamic instability.
3. Pulseless VT: It is a type of sustained VT that does not produce a pulse, blood pressure, or adequate cardiac output, requiring immediate electrical cardioversion or defibrillation to restore a normal heart rhythm.

VT can occur in people with various underlying heart conditions such as coronary artery disease, cardiomyopathy, valvular heart disease, congenital heart defects, and electrolyte imbalances. It can also be triggered by certain medications, substance abuse, or electrical abnormalities in the heart. Prompt diagnosis and treatment of VT are crucial to prevent complications and improve outcomes.

Impedance cardiography is a non-invasive method to measure cardiac output and systemic vascular resistance. It uses low-frequency electrical currents passed through the thorax to measure changes in impedance or resistance to flow during each heartbeat. This allows for the calculation of stroke volume and cardiac output. Impedance cardiography can provide continuous, real-time monitoring of cardiovascular function, making it useful in critical care settings and for tracking changes in patients with heart failure or other cardiovascular conditions.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

Ambulatory Blood Pressure Monitoring (ABPM) is a non-invasive method of measuring blood pressure at regular intervals over a 24-hour period or more. This is typically done using a portable device that is worn on a belt around the waist and connected to a cuff wrapped around the upper arm. The device automatically inflates the cuff and records blood pressure readings at preset intervals, usually every 15 to 30 minutes during the day and every 30 to 60 minutes during the night.

ABPM provides valuable information about blood pressure patterns over an extended period, including how it varies throughout the day and in response to daily activities, posture changes, and sleep. This can help healthcare providers diagnose and manage hypertension more effectively, as well as assess the effectiveness of antihypertensive medications. ABPM is also useful for identifying white coat hypertension, a condition where blood pressure readings are higher in a medical setting than in daily life.

Overall, ambulatory blood pressure monitoring is an important tool in the diagnosis and management of hypertension and related cardiovascular diseases.

Pulmonary ventilation, also known as pulmonary respiration or simply ventilation, is the process of moving air into and out of the lungs to facilitate gas exchange. It involves two main phases: inhalation (or inspiration) and exhalation (or expiration). During inhalation, the diaphragm and external intercostal muscles contract, causing the chest volume to increase and the pressure inside the chest to decrease, which then draws air into the lungs. Conversely, during exhalation, these muscles relax, causing the chest volume to decrease and the pressure inside the chest to increase, which pushes air out of the lungs. This process ensures that oxygen-rich air from the atmosphere enters the alveoli (air sacs in the lungs), where it can diffuse into the bloodstream, while carbon dioxide-rich air from the bloodstream in the capillaries surrounding the alveoli is expelled out of the body.

Nifedipine is an antihypertensive and calcium channel blocker medication. It works by relaxing the muscles of the blood vessels, which helps to lower blood pressure and improve the supply of oxygen and nutrients to the heart. Nifedipine is used to treat high blood pressure (hypertension), angina (chest pain), and certain types of heart rhythm disorders.

In medical terms, nifedipine can be defined as: "A dihydropyridine calcium channel blocker that is used in the treatment of hypertension, angina pectoris, and Raynaud's phenomenon. It works by inhibiting the influx of calcium ions into vascular smooth muscle and cardiac muscle, which results in relaxation of the vascular smooth muscle and decreased workload on the heart."

A chemical stimulation in a medical context refers to the process of activating or enhancing physiological or psychological responses in the body using chemical substances. These chemicals can interact with receptors on cells to trigger specific reactions, such as neurotransmitters and hormones that transmit signals within the nervous system and endocrine system.

Examples of chemical stimulation include the use of medications, drugs, or supplements that affect mood, alertness, pain perception, or other bodily functions. For instance, caffeine can chemically stimulate the central nervous system to increase alertness and decrease feelings of fatigue. Similarly, certain painkillers can chemically stimulate opioid receptors in the brain to reduce the perception of pain.

It's important to note that while chemical stimulation can have therapeutic benefits, it can also have adverse effects if used improperly or in excessive amounts. Therefore, it's essential to follow proper dosing instructions and consult with a healthcare provider before using any chemical substances for stimulation purposes.

Cardiac surgical procedures are operations that are performed on the heart or great vessels (the aorta and vena cava) by cardiothoracic surgeons. These surgeries are often complex and require a high level of skill and expertise. Some common reasons for cardiac surgical procedures include:

1. Coronary artery bypass grafting (CABG): This is a surgery to improve blood flow to the heart in patients with coronary artery disease. During the procedure, a healthy blood vessel from another part of the body is used to create a detour around the blocked or narrowed portion of the coronary artery.
2. Valve repair or replacement: The heart has four valves that control blood flow through and out of the heart. If one or more of these valves become damaged or diseased, they may need to be repaired or replaced. This can be done using artificial valves or valves from animal or human donors.
3. Aneurysm repair: An aneurysm is a weakened area in the wall of an artery that can bulge out and potentially rupture. If an aneurysm occurs in the aorta, it may require surgical repair to prevent rupture.
4. Heart transplantation: In some cases, heart failure may be so severe that a heart transplant is necessary. This involves removing the diseased heart and replacing it with a healthy donor heart.
5. Arrhythmia surgery: Certain types of abnormal heart rhythms (arrhythmias) may require surgical treatment. One such procedure is called the Maze procedure, which involves creating a pattern of scar tissue in the heart to disrupt the abnormal electrical signals that cause the arrhythmia.
6. Congenital heart defect repair: Some people are born with structural problems in their hearts that require surgical correction. These may include holes between the chambers of the heart or abnormal blood vessels.

Cardiac surgical procedures carry risks, including bleeding, infection, stroke, and death. However, for many patients, these surgeries can significantly improve their quality of life and longevity.

Intraventricular injections are a type of medical procedure where medication is administered directly into the cerebral ventricles of the brain. The cerebral ventricles are fluid-filled spaces within the brain that contain cerebrospinal fluid (CSF). This procedure is typically used to deliver drugs that target conditions affecting the central nervous system, such as infections or tumors.

Intraventricular injections are usually performed using a thin, hollow needle that is inserted through a small hole drilled into the skull. The medication is then injected directly into the ventricles, allowing it to circulate throughout the CSF and reach the brain tissue more efficiently than other routes of administration.

This type of injection is typically reserved for situations where other methods of drug delivery are not effective or feasible. It carries a higher risk of complications, such as bleeding, infection, or damage to surrounding tissues, compared to other routes of administration. Therefore, it is usually performed by trained medical professionals in a controlled clinical setting.

Methyl ethers are a type of organic compound where a methyl group (CH3-) is attached to an oxygen atom, which in turn is connected to another carbon atom. They are formed by the process of methylation, where a methyl group replaces a hydrogen atom in another molecule.

Methyl ethers can be found in various natural and synthetic substances. For example, dimethyl ether (CH3-O-CH3) is a common fuel used in refrigeration systems and as a propellant in aerosol sprays. Anisole (CH3-O-C6H5), another methyl ether, is found in anise oil and is used as a flavoring agent and solvent.

It's worth noting that some methyl ethers have been associated with potential health risks, particularly when they are volatile and can be inhaled or ingested. For example, exposure to high levels of dimethyl ether can cause respiratory irritation, headaches, and dizziness. Therefore, it's important to handle these substances with care and follow appropriate safety guidelines.

Myocarditis is an inflammation of the myocardium, which is the middle layer of the heart wall. The myocardium is composed of cardiac muscle cells and is responsible for the heart's pumping function. Myocarditis can be caused by various infectious and non-infectious agents, including viruses, bacteria, fungi, parasites, autoimmune diseases, toxins, and drugs.

In myocarditis, the inflammation can damage the cardiac muscle cells, leading to decreased heart function, arrhythmias (irregular heart rhythms), and in severe cases, heart failure or even sudden death. Symptoms of myocarditis may include chest pain, shortness of breath, fatigue, palpitations, and swelling in the legs, ankles, or abdomen.

The diagnosis of myocarditis is often based on a combination of clinical presentation, laboratory tests, electrocardiogram (ECG), echocardiography, cardiac magnetic resonance imaging (MRI), and endomyocardial biopsy. Treatment depends on the underlying cause and severity of the disease and may include medications to support heart function, reduce inflammation, control arrhythmias, and prevent further damage to the heart muscle. In some cases, hospitalization and intensive care may be necessary.

Intravenous anesthetics are a type of medication that is administered directly into a vein to cause a loss of consciousness and provide analgesia (pain relief) during medical procedures. They work by depressing the central nervous system, inhibiting nerve impulse transmission and ultimately preventing the patient from feeling pain or discomfort during surgery or other invasive procedures.

There are several different types of intravenous anesthetics, each with its own specific properties and uses. Some common examples include propofol, etomidate, ketamine, and barbiturates. These drugs may be used alone or in combination with other medications to provide a safe and effective level of anesthesia for the patient.

The choice of intravenous anesthetic depends on several factors, including the patient's medical history, the type and duration of the procedure, and the desired depth and duration of anesthesia. Anesthesiologists must carefully consider these factors when selecting an appropriate medication regimen for each individual patient.

While intravenous anesthetics are generally safe and effective, they can have side effects and risks, such as respiratory depression, hypotension, and allergic reactions. Anesthesia providers must closely monitor patients during and after the administration of these medications to ensure their safety and well-being.

Lidocaine is a type of local anesthetic that numbs painful areas and is used to prevent pain during certain medical procedures. It works by blocking the nerves that transmit pain signals to the brain. In addition to its use as an anesthetic, lidocaine can also be used to treat irregular heart rates and relieve itching caused by allergic reactions or skin conditions such as eczema.

Lidocaine is available in various forms, including creams, gels, ointments, sprays, solutions, and injectable preparations. It can be applied directly to the skin or mucous membranes, or it can be administered by injection into a muscle or vein. The specific dosage and method of administration will depend on the reason for its use and the individual patient's medical history and current health status.

Like all medications, lidocaine can have side effects, including allergic reactions, numbness that lasts too long, and in rare cases, heart problems or seizures. It is important to follow the instructions of a healthcare provider carefully when using lidocaine to minimize the risk of adverse effects.

Xamoterol is not generally considered to have a medical definition, as it is not an approved or commonly used medication in clinical practice. However, it is a chemical compound that has been studied in the past for its potential therapeutic effects.

Xamoterol is a beta-adrenergic receptor agonist, which means that it binds to and activates certain types of receptors found on cells throughout the body. Specifically, xamoterol is a partial agonist of both beta-1 and beta-2 adrenergic receptors, which are involved in various physiological processes such as heart rate, contractility, and bronchodilation.

In clinical trials, xamoterol was investigated for its potential to improve cardiac function and exercise capacity in patients with chronic heart failure. However, the drug was found to have only modest benefits and was associated with an increased risk of serious arrhythmias, which ultimately led to its discontinuation in further development and use.

Therefore, while xamoterol may have a chemical definition as a beta-adrenergic receptor agonist, it is not commonly used or recognized as a medical term in clinical practice.

A ventricular septal defect (VSD) is a type of congenital heart defect that involves a hole in the wall separating the two lower chambers of the heart, the ventricles. This defect allows oxygenated blood from the left ventricle to mix with deoxygenated blood in the right ventricle, leading to inefficient oxygenation of the body's tissues. The size and location of the hole can vary, and symptoms may range from none to severe, depending on the size of the defect and the amount of blood that is able to shunt between the ventricles. Small VSDs may close on their own over time, while larger defects usually require medical intervention, such as medication or surgery, to prevent complications like pulmonary hypertension and heart failure.

Vasodilation is the widening or increase in diameter of blood vessels, particularly the involuntary relaxation of the smooth muscle in the tunica media (middle layer) of the arteriole walls. This results in an increase in blood flow and a decrease in vascular resistance. Vasodilation can occur due to various physiological and pathophysiological stimuli, such as local metabolic demands, neural signals, or pharmacological agents. It plays a crucial role in regulating blood pressure, tissue perfusion, and thermoregulation.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

Fentanyl is a potent synthetic opioid analgesic, which is similar to morphine but is 50 to 100 times more potent. It is a schedule II prescription drug, typically used to treat patients with severe pain or to manage pain after surgery. It works by binding to the body's opioid receptors, which are found in the brain, spinal cord, and other areas of the body.

Fentanyl can be administered in several forms, including transdermal patches, lozenges, injectable solutions, and tablets that dissolve in the mouth. Illegally manufactured and distributed fentanyl has also become a major public health concern, as it is often mixed with other drugs such as heroin, cocaine, and counterfeit pills, leading to an increase in overdose deaths.

Like all opioids, fentanyl carries a risk of dependence, addiction, and overdose, especially when used outside of medical supervision or in combination with other central nervous system depressants such as alcohol or benzodiazepines. It is important to use fentanyl only as directed by a healthcare provider and to be aware of the potential risks associated with its use.

The autonomic nervous system (ANS) is a component of the peripheral nervous system that regulates involuntary physiological functions, such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. The autonomic pathways refer to the neural connections and signaling processes that allow the ANS to carry out these functions.

The autonomic pathways consist of two main subdivisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). These systems have opposing effects on many organs, with the SNS generally stimulating activity and the PNS inhibiting it. The enteric nervous system, which controls gut function, is sometimes considered a third subdivision of the ANS.

The sympathetic pathway originates in the thoracic and lumbar regions of the spinal cord, with preganglionic neurons synapsing on postganglionic neurons in paravertebral ganglia or prevertebral ganglia. The parasympathetic pathway originates in the brainstem (cranial nerves III, VII, IX, and X) and the sacral region of the spinal cord (S2-S4), with preganglionic neurons synapsing on postganglionic neurons near or within the target organ.

Acetylcholine is the primary neurotransmitter used in both the sympathetic and parasympathetic pathways, although norepinephrine (noradrenaline) is also released by some postganglionic sympathetic neurons. The specific pattern of neural activation and inhibition within the autonomic pathways helps maintain homeostasis and allows for adaptive responses to changes in the internal and external environment.

Gestational age is the length of time that has passed since the first day of the last menstrual period (LMP) in pregnant women. It is the standard unit used to estimate the age of a pregnancy and is typically expressed in weeks. This measure is used because the exact date of conception is often not known, but the start of the last menstrual period is usually easier to recall.

It's important to note that since ovulation typically occurs around two weeks after the start of the LMP, gestational age is approximately two weeks longer than fetal age, which is the actual time elapsed since conception. Medical professionals use both gestational and fetal age to track the development and growth of the fetus during pregnancy.

Adrenergic alpha-antagonists, also known as alpha-blockers, are a class of medications that block the effects of adrenaline and noradrenaline at alpha-adrenergic receptors. These receptors are found in various tissues throughout the body, including the smooth muscle of blood vessels, the heart, the genitourinary system, and the eyes.

When alpha-blockers bind to these receptors, they prevent the activation of the sympathetic nervous system, which is responsible for the "fight or flight" response. This results in a relaxation of the smooth muscle, leading to vasodilation (widening of blood vessels), decreased blood pressure, and increased blood flow.

Alpha-blockers are used to treat various medical conditions, such as hypertension (high blood pressure), benign prostatic hyperplasia (enlarged prostate), pheochromocytoma (a rare tumor of the adrenal gland), and certain types of glaucoma.

Examples of alpha-blockers include doxazosin, prazosin, terazosin, and tamsulosin. Side effects of alpha-blockers may include dizziness, lightheadedness, headache, weakness, and orthostatic hypotension (a sudden drop in blood pressure upon standing).

Lactates, also known as lactic acid, are compounds that are produced by muscles during intense exercise or other conditions of low oxygen supply. They are formed from the breakdown of glucose in the absence of adequate oxygen to complete the full process of cellular respiration. This results in the production of lactate and a hydrogen ion, which can lead to a decrease in pH and muscle fatigue.

In a medical context, lactates may be measured in the blood as an indicator of tissue oxygenation and metabolic status. Elevated levels of lactate in the blood, known as lactic acidosis, can indicate poor tissue perfusion or hypoxia, and may be seen in conditions such as sepsis, cardiac arrest, and severe shock. It is important to note that lactates are not the primary cause of acidemia (low pH) in lactic acidosis, but rather a marker of the underlying process.

Physical education and training (PE/PT) is not a term typically used in medical terminology, but it generally refers to the process of teaching and learning physical skills, knowledge, and behaviors that contribute to an individual's overall health and well-being. According to the World Health Organization (WHO), physical education can be defined as:

"Education through physical activity that is planned, structured, and purposeful. It aims to develop and maintain physical competence, improve health and fitness, enhance personal and social skills, and promote enjoyment of physical activity."

Physical training, on the other hand, typically refers to a more focused and structured approach to improving physical fitness through exercise and other activities. Physical trainers or coaches may work with individuals or groups to develop specific training programs that target areas such as strength, flexibility, endurance, balance, and agility.

In medical contexts, PE/PT may be used to describe interventions aimed at improving physical function, reducing disability, or promoting overall health in patients with various medical conditions. For example, a physical therapy program might be prescribed for someone recovering from an injury or surgery, while a regular exercise routine might be recommended as part of a treatment plan for managing chronic diseases such as diabetes or heart disease.

Captopril is a medication that belongs to a class of drugs called ACE (angiotensin-converting enzyme) inhibitors. It works by blocking the action of a chemical in the body called angiotensin II, which causes blood vessels to narrow and release hormones that can increase blood pressure. By blocking the action of angiotensin II, captopril helps relax and widen blood vessels, which lowers blood pressure and improves blood flow.

Captopril is used to treat high blood pressure (hypertension), congestive heart failure, and to improve survival after a heart attack. It may also be used to protect the kidneys from damage due to diabetes or high blood pressure. The medication comes in the form of tablets that are taken by mouth, usually two to three times per day.

Common side effects of captopril include cough, dizziness, headache, and skin rash. More serious side effects may include allergic reactions, kidney problems, and changes in blood cell counts. It is important for patients taking captopril to follow their doctor's instructions carefully and report any unusual symptoms or side effects promptly.

Pulsatile flow is a type of fluid flow that occurs in a rhythmic, wave-like pattern, typically seen in the cardiovascular system. It refers to the periodic variation in the volume or velocity of a fluid (such as blood) that is caused by the regular beating of the heart. In pulsatile flow, there are periods of high flow followed by periods of low or no flow, which creates a distinct pattern on a graph or tracing. This type of flow is important for maintaining proper function and health in organs and tissues throughout the body.

Heart-assist devices, also known as mechanical circulatory support devices, are medical equipment designed to help the heart function more efficiently. These devices can be used in patients with advanced heart failure who are not responding to medication or other treatments. They work by taking over some or all of the heart's pumping functions, reducing the workload on the heart and improving blood flow to the rest of the body.

There are several types of heart-assist devices, including:

1. Intra-aortic balloon pumps (IABPs): These devices are inserted into the aorta, the large artery that carries blood from the heart to the rest of the body. The IABP inflates and deflates in time with the heartbeat, helping to improve blood flow to the coronary arteries and reduce the workload on the heart.
2. Ventricular assist devices (VADs): These devices are more invasive than IABPs and are used to support the function of one or both ventricles, the lower chambers of the heart. VADs can be used to support the heart temporarily while a patient recovers from surgery or heart failure, or they can be used as a long-term solution for patients who are not candidates for a heart transplant.
3. Total artificial hearts (TAHs): These devices replace both ventricles and all four valves of the heart. TAHs are used in patients who are not candidates for a heart transplant and have severe biventricular failure, meaning that both ventricles are no longer functioning properly.

Heart-assist devices can be life-saving for some patients with advanced heart failure, but they also carry risks, such as infection, bleeding, and device malfunction. As with any medical treatment, the benefits and risks of using a heart-assist device must be carefully weighed for each individual patient.

"Sex characteristics" refer to the anatomical, chromosomal, and genetic features that define males and females. These include both primary sex characteristics (such as reproductive organs like ovaries or testes) and secondary sex characteristics (such as breasts or facial hair) that typically develop during puberty. Sex characteristics are primarily determined by the presence of either X or Y chromosomes, with XX individuals usually developing as females and XY individuals usually developing as males, although variations and exceptions to this rule do occur.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Head-down tilt (HDT) is a positioning technique often used in medical settings, particularly during diagnostic procedures or treatment interventions. In this position, the person lies down on a specially designed table with their head tilted below the horizontal plane, typically at an angle of 6 degrees to 15 degrees, but sometimes as steep as 90 degrees. This posture allows for various medical evaluations such as carotid sinus massage or intracranial pressure monitoring. It is also used in space medicine to simulate some effects of weightlessness on the human body during spaceflight. Please note that prolonged exposure to head-down tilt can have physiological consequences, including changes in blood pressure, heart rate, and eye function, which should be monitored and managed by healthcare professionals.

Oxprenolol is a non-selective beta blocker and partial agonist of beta-adrenergic receptors. It works by blocking the effects of certain chemicals on the heart and blood vessels, which can help to reduce heart rate, blood pressure, and strain on the heart. Oxprenolol is used to treat angina (chest pain), high blood pressure, irregular heartbeats, and tremors. It may also be used for other purposes not listed here.

It's important to note that oxprenolol should only be taken under the supervision of a medical professional, as it can have significant interactions with other medications and medical conditions. Additionally, sudden discontinuation of oxprenolol should be avoided, as it can lead to rebound effects such as increased heart rate and blood pressure.

Vasoconstrictor agents are substances that cause the narrowing of blood vessels by constricting the smooth muscle in their walls. This leads to an increase in blood pressure and a decrease in blood flow. They work by activating the sympathetic nervous system, which triggers the release of neurotransmitters such as norepinephrine and epinephrine that bind to alpha-adrenergic receptors on the smooth muscle cells of the blood vessel walls, causing them to contract.

Vasoconstrictor agents are used medically for a variety of purposes, including:

* Treating hypotension (low blood pressure)
* Controlling bleeding during surgery or childbirth
* Relieving symptoms of nasal congestion in conditions such as the common cold or allergies

Examples of vasoconstrictor agents include phenylephrine, oxymetazoline, and epinephrine. It's important to note that prolonged use or excessive doses of vasoconstrictor agents can lead to rebound congestion and other adverse effects, so they should be used with caution and under the guidance of a healthcare professional.

Hydralazine is an antihypertensive medication, which means it is used to treat high blood pressure. It works by relaxing and widening the blood vessels, making it easier for the heart to pump blood through the body. This can help reduce the workload on the heart and lower blood pressure. Hydralazine is available in oral tablet form and is typically prescribed to be taken several times a day.

Hydralazine belongs to a class of medications called vasodilators, which work by relaxing the muscle in the walls of the blood vessels, causing them to widen. This increases the amount of blood that can flow through the blood vessels and reduces the pressure within them. Hydralazine is often used in combination with other medications to treat high blood pressure.

It's important to note that hydralazine should be used under the close supervision of a healthcare provider, as it can cause side effects such as headache, dizziness, and rapid heartbeat. It may also interact with certain other medications, so it is important to inform your doctor of all medications you are taking before starting hydralazine.

I couldn't find a medical definition for "Depression, Chemical" as it is not a recognized medical term. However, I can provide you with information about chemical imbalances in the brain that are associated with depression.

Major depressive disorder (MDD), commonly referred to as depression, is believed to be caused by a combination of genetic, environmental, and physiological factors. While there is no definitive evidence that depression is solely caused by a "chemical imbalance," neurotransmitter irregularities in the brain are associated with depressive symptoms. Neurotransmitters are chemical messengers that transmit signals in the brain and other parts of the body. Some of the primary neurotransmitters involved in mood regulation include serotonin, norepinephrine, and dopamine.

In depression, it is thought that there may be alterations in the functioning of these neurotransmitter systems, leading to an imbalance. For example:

1. Serotonin: Low levels of serotonin are associated with depressive symptoms. Selective serotonin reuptake inhibitors (SSRIs), a common class of antidepressants, work by increasing the availability of serotonin in the synapse (the space between neurons) to improve communication between brain cells.
2. Norepinephrine: Imbalances in norepinephrine levels can contribute to depressive symptoms and anxiety. Norepinephrine reuptake inhibitors (NRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs) are medications that target norepinephrine to help alleviate depression.
3. Dopamine: Deficiencies in dopamine can lead to depressive symptoms, anhedonia (the inability to feel pleasure), and motivation loss. Some antidepressants, like bupropion, work by increasing dopamine levels in the brain.

In summary, while "Chemical Depression" is not a recognized medical term, chemical imbalances in neurotransmitter systems are associated with depressive symptoms. However, depression is a complex disorder that cannot be solely attributed to a single cause or a simple chemical imbalance. It is essential to consider multiple factors when diagnosing and treating depression.

The Stellate Ganglion is a part of the sympathetic nervous system. It's a collection of nerve cells (a ganglion) located in the neck, more specifically at the level of the sixth and seventh cervical vertebrae. The stellate ganglion is formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion.

This ganglion plays a crucial role in the body's "fight or flight" response, providing sympathetic innervation to the head, neck, upper extremities, and heart. It's responsible for various functions including regulation of blood flow, sweat gland activity, and contributing to the sensory innervation of the head and neck.

Stellate ganglion block is a medical procedure used to diagnose or treat certain conditions like pain disorders, by injecting local anesthetic near the stellate ganglion to numb the area and interrupt nerve signals.

Halothane is a general anesthetic agent, which is a volatile liquid that evaporates easily and can be inhaled. It is used to produce and maintain general anesthesia (a state of unconsciousness) during surgical procedures. Halothane is known for its rapid onset and offset of action, making it useful for both induction and maintenance of anesthesia.

The medical definition of Halothane is:

Halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) is a volatile liquid general anesthetic agent with a mild, sweet odor. It is primarily used for the induction and maintenance of general anesthesia in surgical procedures due to its rapid onset and offset of action. Halothane is administered via inhalation and acts by depressing the central nervous system, leading to a reversible loss of consciousness and analgesia.

It's important to note that Halothane has been associated with rare cases of severe liver injury (hepatotoxicity) and anaphylaxis (a severe, life-threatening allergic reaction). These risks have led to the development and use of alternative general anesthetic agents with better safety profiles.

Cardiac-gated imaging techniques are medical diagnostic procedures that involve synchronizing the acquisition of data with the electrical activity of the heart, typically the R-wave of the electrocardiogram (ECG). This allows for the capture of images during specific phases of the cardiac cycle, reducing motion artifacts and improving image quality. These techniques are commonly used in various imaging modalities such as echocardiography, cardiac magnetic resonance imaging (MRI), and nuclear medicine studies like myocardial perfusion imaging. By obtaining images at specific points in the cardiac cycle, these techniques help assess heart function, wall motion abnormalities, valve function, and myocardial perfusion, ultimately aiding in the diagnosis and management of various cardiovascular diseases.

Inhalational anesthetics are a type of general anesthetic that is administered through the person's respiratory system. They are typically delivered in the form of vapor or gas, which is inhaled through a mask or breathing tube. Commonly used inhalational anesthetics include sevoflurane, desflurane, isoflurane, and nitrous oxide. These agents work by depressing the central nervous system, leading to a loss of consciousness and an inability to feel pain. They are often used for their rapid onset and offset of action, making them useful for both induction and maintenance of anesthesia during surgical procedures.

I apologize, but "sheep" is not a term that has a medical definition. It is a common animal with the scientific name Ovis aries. If you have any medical or health-related questions, I would be happy to try and help answer those for you.

Creatine kinase (CK) is a muscle enzyme that is normally present in small amounts in the blood. It is primarily found in tissues that require a lot of energy, such as the heart, brain, and skeletal muscles. When these tissues are damaged or injured, CK is released into the bloodstream, causing the levels to rise.

Creatine kinase exists in several forms, known as isoenzymes, which can be measured in the blood to help identify the location of tissue damage. The three main isoenzymes are:

1. CK-MM: Found primarily in skeletal muscle
2. CK-MB: Found primarily in heart muscle
3. CK-BB: Found primarily in the brain

Elevated levels of creatine kinase, particularly CK-MB, can indicate damage to the heart muscle, such as occurs with a heart attack. Similarly, elevated levels of CK-BB may suggest brain injury or disease. Overall, measuring creatine kinase levels is a useful diagnostic tool for assessing tissue damage and determining the severity of injuries or illnesses.

Preanesthetic medication, also known as premedication, refers to the administration of medications before anesthesia to help prepare the patient for the upcoming procedure. These medications can serve various purposes, such as:

1. Anxiolysis: Reducing anxiety and promoting relaxation in patients before surgery.
2. Amnesia: Causing temporary memory loss to help patients forget the events leading up to the surgery.
3. Analgesia: Providing pain relief to minimize discomfort during and after the procedure.
4. Antisialagogue: Decreasing saliva production to reduce the risk of aspiration during intubation.
5. Bronchodilation: Relaxing bronchial smooth muscles, which can help improve respiratory function in patients with obstructive lung diseases.
6. Antiemetic: Preventing or reducing the likelihood of postoperative nausea and vomiting.
7. Sedation: Inducing a state of calmness and drowsiness to facilitate a smooth induction of anesthesia.

Common preanesthetic medications include benzodiazepines (e.g., midazolam), opioids (e.g., fentanyl), anticholinergics (e.g., glycopyrrolate), and H1-antihistamines (e.g., diphenhydramine). The choice of preanesthetic medication depends on the patient's medical history, comorbidities, and the type of anesthesia to be administered.

Sinus tachycardia is a type of rapid heart rate, characterized by an abnormally fast sinus rhythm, with a rate greater than 100 beats per minute in adults. The sinoatrial node (SA node), which is the natural pacemaker of the heart, generates these impulses regularly and at an increased rate.

Sinus tachycardia is usually a physiological response to various stimuli or conditions, such as physical exertion, strong emotions, fever, anxiety, pain, or certain medications. It can also be caused by hormonal imbalances, anemia, hyperthyroidism, or other medical disorders.

In most cases, sinus tachycardia is not harmful and resolves once the underlying cause is addressed. However, if it occurs persistently or is associated with symptoms like palpitations, shortness of breath, dizziness, or chest discomfort, further evaluation by a healthcare professional is recommended to rule out any underlying heart conditions or other medical issues.

"Motor activity" is a general term used in the field of medicine and neuroscience to refer to any kind of physical movement or action that is generated by the body's motor system. The motor system includes the brain, spinal cord, nerves, and muscles that work together to produce movements such as walking, talking, reaching for an object, or even subtle actions like moving your eyes.

Motor activity can be voluntary, meaning it is initiated intentionally by the individual, or involuntary, meaning it is triggered automatically by the nervous system without conscious control. Examples of voluntary motor activity include deliberately lifting your arm or kicking a ball, while examples of involuntary motor activity include heartbeat, digestion, and reflex actions like jerking your hand away from a hot stove.

Abnormalities in motor activity can be a sign of neurological or muscular disorders, such as Parkinson's disease, cerebral palsy, or multiple sclerosis. Assessment of motor activity is often used in the diagnosis and treatment of these conditions.

Atropine derivatives are a class of drugs that are chemically related to atropine, an alkaloid found in the nightshade family of plants. These drugs have anticholinergic properties, which means they block the action of the neurotransmitter acetylcholine in the body.

Atropine derivatives can be used for a variety of medical purposes, including:

1. Treating motion sickness and vertigo
2. Dilating the pupils during eye examinations
3. Reducing saliva production during surgical procedures
4. Treating certain types of poisoning, such as organophosphate or nerve gas poisoning
5. Managing symptoms of some neurological disorders, such as Parkinson's disease and myasthenia gravis

Some examples of atropine derivatives include hyoscyamine, scopolamine, and ipratropium. These drugs can have side effects, including dry mouth, blurred vision, constipation, difficulty urinating, and rapid heartbeat. They should be used with caution and under the supervision of a healthcare provider.

Postural Orthostatic Tachycardia Syndrome (POTS) is a condition characterized by an abnormally rapid heart rate (tachycardia) that occurs upon standing, leading to symptoms such as dizziness, lightheadedness, and fainting. The diagnostic criteria for POTS include:

1. A heart rate increase of 30 beats per minute or more within the first 10 minutes of standing or a heart rate of 120 beats per minute or more within the first 10 minutes of standing, measured by a heart rate monitor.
2. The presence of symptoms such as lightheadedness, dizziness, blurred vision, weakness, fatigue, headache, shortness of breath, or chest pain upon standing that are relieved by lying down.
3. Symptoms must be present for at least three months and occur in the absence of other medical conditions that could explain them.

POTS is thought to be caused by a dysfunction of the autonomic nervous system, which controls involuntary functions such as heart rate and blood pressure. Treatment may include lifestyle modifications, such as increasing fluid and salt intake, wearing compression stockings, and avoiding prolonged standing or sitting. Medications that help regulate blood pressure and heart rate may also be prescribed.

Prenatal ultrasonography, also known as obstetric ultrasound, is a medical diagnostic procedure that uses high-frequency sound waves to create images of the developing fetus, placenta, and amniotic fluid inside the uterus. It is a non-invasive and painless test that is widely used during pregnancy to monitor the growth and development of the fetus, detect any potential abnormalities or complications, and determine the due date.

During the procedure, a transducer (a small handheld device) is placed on the mother's abdomen and moved around to capture images from different angles. The sound waves travel through the mother's body and bounce back off the fetus, producing echoes that are then converted into electrical signals and displayed as images on a screen.

Prenatal ultrasonography can be performed at various stages of pregnancy, including early pregnancy to confirm the pregnancy and detect the number of fetuses, mid-pregnancy to assess the growth and development of the fetus, and late pregnancy to evaluate the position of the fetus and determine if it is head down or breech. It can also be used to guide invasive procedures such as amniocentesis or chorionic villus sampling.

Overall, prenatal ultrasonography is a valuable tool in modern obstetrics that helps ensure the health and well-being of both the mother and the developing fetus.

The Chi-square distribution is a continuous probability distribution that is often used in statistical hypothesis testing. It is the distribution of a sum of squares of k independent standard normal random variables. The resulting quantity follows a chi-square distribution with k degrees of freedom, denoted as χ²(k).

The probability density function (pdf) of the Chi-square distribution with k degrees of freedom is given by:

f(x; k) = (1/ (2^(k/2) * Γ(k/2))) \* x^((k/2)-1) \* e^(-x/2), for x > 0 and 0, otherwise.

Where Γ(k/2) is the gamma function evaluated at k/2. The mean and variance of a Chi-square distribution with k degrees of freedom are k and 2k, respectively.

The Chi-square distribution has various applications in statistical inference, including testing goodness-of-fit, homogeneity of variances, and independence in contingency tables.

Dizziness is a term used to describe a range of sensations, such as feeling lightheaded, faint, unsteady, or a false sense of spinning or moving. Medically, dizziness is often described as a non-specific symptom that can be caused by various underlying conditions or factors. These may include:

1. Inner ear disorders (such as benign paroxysmal positional vertigo, labyrinthitis, vestibular neuronitis, or Meniere's disease)
2. Cardiovascular problems (like low blood pressure, arrhythmias, or orthostatic hypotension)
3. Neurological issues (such as migraines, multiple sclerosis, or stroke)
4. Anxiety disorders and panic attacks
5. Side effects of medications
6. Dehydration or overheating
7. Infections (like viral infections or bacterial meningitis)
8. Head or neck injuries
9. Low blood sugar levels (hypoglycemia)

It is essential to consult a healthcare professional if you experience persistent dizziness, as it can be a sign of a more severe underlying condition. The appropriate treatment will depend on the specific cause of the dizziness.

Respiratory physiological phenomena refer to the various mechanical, chemical, and biological processes and functions that occur in the respiratory system during breathing and gas exchange. These phenomena include:

1. Ventilation: The movement of air into and out of the lungs, which is achieved through the contraction and relaxation of the diaphragm and intercostal muscles.
2. Gas Exchange: The diffusion of oxygen (O2) from the alveoli into the bloodstream and carbon dioxide (CO2) from the bloodstream into the alveoli.
3. Respiratory Mechanics: The physical properties and forces that affect the movement of air in and out of the lungs, such as lung compliance, airway resistance, and chest wall elasticity.
4. Control of Breathing: The regulation of ventilation by the central nervous system through the integration of sensory information from chemoreceptors and mechanoreceptors in the respiratory system.
5. Acid-Base Balance: The maintenance of a stable pH level in the blood through the regulation of CO2 elimination and bicarbonate balance by the respiratory and renal systems.
6. Oxygen Transport: The binding of O2 to hemoglobin in the red blood cells and its delivery to the tissues for metabolic processes.
7. Defense Mechanisms: The various protective mechanisms that prevent the entry and colonization of pathogens and foreign particles into the respiratory system, such as mucociliary clearance, cough reflex, and immune responses.

Plethysmography is a non-invasive medical technique used to measure changes in volume or blood flow within an organ or body part, typically in the lungs or extremities. There are several types of plethysmography, including:

1. **Whole Body Plethysmography (WBP):** This type of plethysmography is used to assess lung function and volumes by measuring changes in pressure within a sealed chamber that contains the patient's entire body except for their head. The patient breathes normally while wearing a nose clip, allowing technicians to analyze respiratory patterns, airflow, and lung volume changes.
2. **Segmental or Local Plethysmography:** This technique measures volume or blood flow changes in specific body parts, such as the limbs or digits. It can help diagnose and monitor conditions affecting peripheral circulation, like deep vein thrombosis, arterial occlusive disease, or Raynaud's phenomenon.
3. **Impedance Plethysmography (IPG):** This non-invasive method uses electrical impedance to estimate changes in blood volume within an organ or body part. By applying a small electrical current and measuring the opposition to flow (impedance), technicians can determine variations in blood volume, which can help diagnose conditions like deep vein thrombosis or heart failure.
4. **Optical Plethysmography:** This technique uses light to measure changes in blood volume, typically in the skin or mucous membranes. By shining a light on the area and analyzing the reflected or transmitted light, technicians can detect variations in blood volume related to cardiac output, respiration, or other physiological factors.

Overall, plethysmography is an essential tool for diagnosing and monitoring various medical conditions affecting circulation, respiratory function, and organ volumes.

Calcium channel blockers (CCBs) are a class of medications that work by inhibiting the influx of calcium ions into cardiac and smooth muscle cells. This action leads to relaxation of the muscles, particularly in the blood vessels, resulting in decreased peripheral resistance and reduced blood pressure. Calcium channel blockers also have anti-arrhythmic effects and are used in the management of various cardiovascular conditions such as hypertension, angina, and certain types of arrhythmias.

Calcium channel blockers can be further classified into two main categories based on their chemical structure: dihydropyridines (e.g., nifedipine, amlodipine) and non-dihydropyridines (e.g., verapamil, diltiazem). Dihydropyridines are more selective for vascular smooth muscle and have a greater effect on blood pressure than heart rate or conduction. Non-dihydropyridines have a more significant impact on cardiac conduction and contractility, in addition to their vasodilatory effects.

It is important to note that calcium channel blockers may interact with other medications and should be used under the guidance of a healthcare professional. Potential side effects include dizziness, headache, constipation, and peripheral edema.

"Newborn animals" refers to the very young offspring of animals that have recently been born. In medical terminology, newborns are often referred to as "neonates," and they are classified as such from birth until about 28 days of age. During this time period, newborn animals are particularly vulnerable and require close monitoring and care to ensure their survival and healthy development.

The specific needs of newborn animals can vary widely depending on the species, but generally, they require warmth, nutrition, hydration, and protection from harm. In many cases, newborns are unable to regulate their own body temperature or feed themselves, so they rely heavily on their mothers for care and support.

In medical settings, newborn animals may be examined and treated by veterinarians to ensure that they are healthy and receiving the care they need. This can include providing medical interventions such as feeding tubes, antibiotics, or other treatments as needed to address any health issues that arise. Overall, the care and support of newborn animals is an important aspect of animal medicine and conservation efforts.

A cross-sectional study is a type of observational research design that examines the relationship between variables at one point in time. It provides a snapshot or a "cross-section" of the population at a particular moment, allowing researchers to estimate the prevalence of a disease or condition and identify potential risk factors or associations.

In a cross-sectional study, data is collected from a sample of participants at a single time point, and the variables of interest are measured simultaneously. This design can be used to investigate the association between exposure and outcome, but it cannot establish causality because it does not follow changes over time.

Cross-sectional studies can be conducted using various data collection methods, such as surveys, interviews, or medical examinations. They are often used in epidemiology to estimate the prevalence of a disease or condition in a population and to identify potential risk factors that may contribute to its development. However, because cross-sectional studies only provide a snapshot of the population at one point in time, they cannot account for changes over time or determine whether exposure preceded the outcome.

Therefore, while cross-sectional studies can be useful for generating hypotheses and identifying potential associations between variables, further research using other study designs, such as cohort or case-control studies, is necessary to establish causality and confirm any findings.

I apologize for any confusion, but "Pyridazines" is not a medical term. It is a chemical term that refers to a class of heterocyclic organic compounds which contain a six-membered ring with two nitrogen atoms. These types of compounds are often used in the synthesis of various pharmaceuticals and agrochemicals, but "Pyridazines" itself is not a medical concept or diagnosis. If you have any questions related to medicine or health, I would be happy to try to help answer those for you.

Anesthetics are medications that are used to block or reduce feelings of pain and sensation, either locally in a specific area of the body or generally throughout the body. They work by depressing the nervous system, interrupting the communication between nerves and the brain. Anesthetics can be administered through various routes such as injection, inhalation, or topical application, depending on the type and the desired effect. There are several classes of anesthetics, including:

1. Local anesthetics: These numb a specific area of the body and are commonly used during minor surgical procedures, dental work, or to relieve pain from injuries. Examples include lidocaine, prilocaine, and bupivacaine.
2. Regional anesthetics: These block nerve impulses in a larger area of the body, such as an arm or leg, and can be used for more extensive surgical procedures. They are often administered through a catheter to provide continuous pain relief over a longer period. Examples include spinal anesthesia, epidural anesthesia, and peripheral nerve blocks.
3. General anesthetics: These cause a state of unconsciousness and are used for major surgical procedures or when the patient needs to be completely immobile during a procedure. They can be administered through inhalation or injection and affect the entire body. Examples include propofol, sevoflurane, and isoflurane.

Anesthetics are typically safe when used appropriately and under medical supervision. However, they can have side effects such as drowsiness, nausea, and respiratory depression. Proper dosing and monitoring by a healthcare professional are essential to minimize the risks associated with anesthesia.

Diuretics are a type of medication that increase the production of urine and help the body eliminate excess fluid and salt. They work by interfering with the reabsorption of sodium in the kidney tubules, which in turn causes more water to be excreted from the body. Diuretics are commonly used to treat conditions such as high blood pressure, heart failure, liver cirrhosis, and kidney disease. There are several types of diuretics, including loop diuretics, thiazide diuretics, potassium-sparing diuretics, and osmotic diuretics, each with its own mechanism of action and potential side effects. It is important to use diuretics under the guidance of a healthcare professional, as they can interact with other medications and have an impact on electrolyte balance in the body.

Lower Body Negative Pressure (LBNP) is a medical term that refers to the application of a negative pressure (below atmospheric pressure) to the lower body, while the upper body remains at normal atmospheric pressure. This is typically achieved through the use of an air-tight chamber or suit that covers the lower body from the waist down.

The negative pressure causes fluid to be drawn towards the lower body, which can simulate the effects of weightlessness or reduced gravity on the cardiovascular system. LBNP is often used in research settings to study the physiological responses to changes in gravitational forces, as well as in clinical settings to help prevent or treat various medical conditions, such as orthostatic intolerance, venous ulcers, and chronic wounds.

Atrial septal defect (ASD) is a type of congenital heart defect that involves the septum, which is the wall that separates the two upper chambers of the heart (atria). An ASD is a hole or abnormal opening in the atrial septum, allowing oxygen-rich blood to leak into the oxygen-poor blood chambers in the heart. This leads to an overload of blood in the right side of the heart, which can cause enlargement of the heart and increased work for the right ventricle.

ASDs can vary in size, and small defects may not cause any symptoms or require treatment. Larger defects, however, can result in symptoms such as shortness of breath, fatigue, and heart rhythm abnormalities. Over time, if left untreated, ASDs can lead to complications like pulmonary hypertension, atrial fibrillation, and stroke.

Treatment for ASD typically involves surgical closure of the defect or catheter-based procedures using devices to close the hole. The choice of treatment depends on factors such as the size and location of the defect, the patient's age and overall health, and the presence of any coexisting conditions.

Bisoprolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and heart failure. It works by blocking the effects of certain hormones on the heart and blood vessels, which helps to lower heart rate, reduce the force of heart contractions, and decrease blood vessel constriction. This can lead to decreased workload on the heart, improved blood flow, and reduced oxygen demand.

Bisoprolol is available in immediate-release and extended-release forms, and it is typically taken orally once or twice a day. Common side effects of bisoprolol include dizziness, fatigue, and cold hands and feet. It is important to follow the dosage instructions provided by your healthcare provider and to report any bothersome or persistent side effects promptly.

Like all medications, bisoprolol can have potential risks and benefits, and it may not be suitable for everyone. Your healthcare provider will consider your individual medical history and current health status when determining whether bisoprolol is an appropriate treatment option for you.

A drug interaction is the effect of combining two or more drugs, or a drug and another substance (such as food or alcohol), which can alter the effectiveness or side effects of one or both of the substances. These interactions can be categorized as follows:

1. Pharmacodynamic interactions: These occur when two or more drugs act on the same target organ or receptor, leading to an additive, synergistic, or antagonistic effect. For example, taking a sedative and an antihistamine together can result in increased drowsiness due to their combined depressant effects on the central nervous system.
2. Pharmacokinetic interactions: These occur when one drug affects the absorption, distribution, metabolism, or excretion of another drug. For example, taking certain antibiotics with grapefruit juice can increase the concentration of the antibiotic in the bloodstream, leading to potential toxicity.
3. Food-drug interactions: Some drugs may interact with specific foods, affecting their absorption, metabolism, or excretion. An example is the interaction between warfarin (a blood thinner) and green leafy vegetables, which can increase the risk of bleeding due to enhanced vitamin K absorption from the vegetables.
4. Drug-herb interactions: Some herbal supplements may interact with medications, leading to altered drug levels or increased side effects. For instance, St. John's Wort can decrease the effectiveness of certain antidepressants and oral contraceptives by inducing their metabolism.
5. Drug-alcohol interactions: Alcohol can interact with various medications, causing additive sedative effects, impaired judgment, or increased risk of liver damage. For example, combining alcohol with benzodiazepines or opioids can lead to dangerous levels of sedation and respiratory depression.

It is essential for healthcare providers and patients to be aware of potential drug interactions to minimize adverse effects and optimize treatment outcomes.

"Nonlinear dynamics is a branch of mathematics and physics that deals with the study of systems that exhibit nonlinear behavior, where the output is not directly proportional to the input. In the context of medicine, nonlinear dynamics can be used to model complex biological systems such as the human cardiovascular system or the brain, where the interactions between different components can lead to emergent properties and behaviors that are difficult to predict using traditional linear methods. Nonlinear dynamic models can help to understand the underlying mechanisms of these systems, make predictions about their behavior, and develop interventions to improve health outcomes."

Propofol is a short-acting medication that is primarily used for the induction and maintenance of general anesthesia during procedures such as surgery. It belongs to a class of drugs called hypnotics or sedatives, which work by depressing the central nervous system to produce a calming effect. Propofol can also be used for sedation in mechanically ventilated patients in intensive care units and for procedural sedation in various diagnostic and therapeutic procedures outside the operating room.

The medical definition of Propofol is:
A rapid-onset, short-duration intravenous anesthetic agent that produces a hypnotic effect and is used for induction and maintenance of general anesthesia, sedation in mechanically ventilated patients, and procedural sedation. It acts by enhancing the inhibitory effects of gamma-aminobutyric acid (GABA) in the brain, leading to a decrease in neuronal activity and a reduction in consciousness. Propofol has a rapid clearance and distribution, allowing for quick recovery after discontinuation of its administration.

An acute disease is a medical condition that has a rapid onset, develops quickly, and tends to be short in duration. Acute diseases can range from minor illnesses such as a common cold or flu, to more severe conditions such as pneumonia, meningitis, or a heart attack. These types of diseases often have clear symptoms that are easy to identify, and they may require immediate medical attention or treatment.

Acute diseases are typically caused by an external agent or factor, such as a bacterial or viral infection, a toxin, or an injury. They can also be the result of a sudden worsening of an existing chronic condition. In general, acute diseases are distinct from chronic diseases, which are long-term medical conditions that develop slowly over time and may require ongoing management and treatment.

Examples of acute diseases include:

* Acute bronchitis: a sudden inflammation of the airways in the lungs, often caused by a viral infection.
* Appendicitis: an inflammation of the appendix that can cause severe pain and requires surgical removal.
* Gastroenteritis: an inflammation of the stomach and intestines, often caused by a viral or bacterial infection.
* Migraine headaches: intense headaches that can last for hours or days, and are often accompanied by nausea, vomiting, and sensitivity to light and sound.
* Myocardial infarction (heart attack): a sudden blockage of blood flow to the heart muscle, often caused by a buildup of plaque in the coronary arteries.
* Pneumonia: an infection of the lungs that can cause coughing, chest pain, and difficulty breathing.
* Sinusitis: an inflammation of the sinuses, often caused by a viral or bacterial infection.

It's important to note that while some acute diseases may resolve on their own with rest and supportive care, others may require medical intervention or treatment to prevent complications and promote recovery. If you are experiencing symptoms of an acute disease, it is always best to seek medical attention to ensure proper diagnosis and treatment.

Microinjection is a medical technique that involves the use of a fine, precise needle to inject small amounts of liquid or chemicals into microscopic structures, cells, or tissues. This procedure is often used in research settings to introduce specific substances into individual cells for study purposes, such as introducing DNA or RNA into cell nuclei to manipulate gene expression.

In clinical settings, microinjections may be used in various medical and cosmetic procedures, including:

1. Intracytoplasmic Sperm Injection (ICSI): A type of assisted reproductive technology where a single sperm is injected directly into an egg to increase the chances of fertilization during in vitro fertilization (IVF) treatments.
2. Botulinum Toxin Injections: Microinjections of botulinum toxin (Botox, Dysport, or Xeomin) are used for cosmetic purposes to reduce wrinkles and fine lines by temporarily paralyzing the muscles responsible for their formation. They can also be used medically to treat various neuromuscular disorders, such as migraines, muscle spasticity, and excessive sweating (hyperhidrosis).
3. Drug Delivery: Microinjections may be used to deliver drugs directly into specific tissues or organs, bypassing the systemic circulation and potentially reducing side effects. This technique can be particularly useful in treating localized pain, delivering growth factors for tissue regeneration, or administering chemotherapy agents directly into tumors.
4. Gene Therapy: Microinjections of genetic material (DNA or RNA) can be used to introduce therapeutic genes into cells to treat various genetic disorders or diseases, such as cystic fibrosis, hemophilia, or cancer.

Overall, microinjection is a highly specialized and precise technique that allows for the targeted delivery of substances into small structures, cells, or tissues, with potential applications in research, medical diagnostics, and therapeutic interventions.

Vasovagal syncope is a type of fainting (syncope) that occurs when the body overreacts to certain triggers, such as the sight of blood or extreme emotional distress. This reaction causes the heart rate and blood pressure to drop, leading to reduced blood flow to the brain and loss of consciousness. Vasovagal syncope is usually not a cause for concern and does not typically indicate a serious underlying medical condition. However, it can be dangerous if it occurs during activities such as driving or operating heavy machinery. If you experience frequent episodes of vasovagal syncope, it is important to speak with a healthcare provider for evaluation and treatment options.

The solitary nucleus, also known as the nucleus solitarius, is a collection of neurons located in the medulla oblongata region of the brainstem. It plays a crucial role in the processing and integration of sensory information, particularly taste and visceral afferent fibers from internal organs. The solitary nucleus receives inputs from various cranial nerves, including the glossopharyngeal (cranial nerve IX) and vagus nerves (cranial nerve X), and is involved in reflex responses related to swallowing, vomiting, and cardiovascular regulation.

Phonocardiography is a non-invasive medical procedure that involves the graphical representation and analysis of sounds produced by the heart. It uses a device called a phonocardiograph to record these sounds, which are then displayed as waveforms on a screen. The procedure is often used in conjunction with other diagnostic techniques, such as electrocardiography (ECG), to help diagnose various heart conditions, including valvular heart disease and heart murmurs.

During the procedure, a specialized microphone called a phonendoscope is placed on the chest wall over the area of the heart. The microphone picks up the sounds generated by the heart's movements, such as the closing and opening of the heart valves, and transmits them to the phonocardiograph. The phonocardiograph then converts these sounds into a visual representation, which can be analyzed for any abnormalities or irregularities in the heart's function.

Phonocardiography is a valuable tool for healthcare professionals, as it can provide important insights into the health and functioning of the heart. By analyzing the waveforms produced during phonocardiography, doctors can identify any potential issues with the heart's valves or other structures, which may require further investigation or treatment. Overall, phonocardiography is an essential component of modern cardiac diagnostics, helping to ensure that patients receive accurate and timely diagnoses for their heart conditions.

I'm sorry for any confusion, but "Sports" is not a medical term. It refers to physical activities that are governed by a set of rules and often engaged in competitively. However, there are fields such as Sports Medicine and Exercise Science that deal with various aspects of physical activity, fitness, and sports-related injuries or conditions. If you have any questions related to these areas, I'd be happy to try to help!

Intravenous anesthesia, also known as IV anesthesia, is a type of anesthesia that involves the administration of one or more drugs into a patient's vein to achieve a state of unconsciousness and analgesia (pain relief) during medical procedures. The drugs used in intravenous anesthesia can include sedatives, hypnotics, analgesics, and muscle relaxants, which are carefully selected and dosed based on the patient's medical history, physical status, and the type and duration of the procedure.

The administration of IV anesthesia is typically performed by a trained anesthesiologist or nurse anesthetist, who monitors the patient's vital signs and adjusts the dosage of the drugs as needed to ensure the patient's safety and comfort throughout the procedure. The onset of action for IV anesthesia is relatively rapid, usually within minutes, and the depth and duration of anesthesia can be easily titrated to meet the needs of the individual patient.

Compared to general anesthesia, which involves the administration of inhaled gases or vapors to achieve a state of unconsciousness, intravenous anesthesia is associated with fewer adverse effects on respiratory and cardiovascular function, and may be preferred for certain types of procedures or patients. However, like all forms of anesthesia, IV anesthesia carries risks and potential complications, including allergic reactions, infection, bleeding, and respiratory depression, and requires careful monitoring and management by trained medical professionals.

In epidemiology, the incidence of a disease is defined as the number of new cases of that disease within a specific population over a certain period of time. It is typically expressed as a rate, with the number of new cases in the numerator and the size of the population at risk in the denominator. Incidence provides information about the risk of developing a disease during a given time period and can be used to compare disease rates between different populations or to monitor trends in disease occurrence over time.

Exercise therapy is a type of medical treatment that uses physical movement and exercise to improve a patient's physical functioning, mobility, and overall health. It is often used as a component of rehabilitation programs for individuals who have experienced injuries, illnesses, or surgeries that have impaired their ability to move and function normally.

Exercise therapy may involve a range of activities, including stretching, strengthening, balance training, aerobic exercise, and functional training. The specific exercises used will depend on the individual's needs, goals, and medical condition.

The benefits of exercise therapy include:

* Improved strength and flexibility
* Increased endurance and stamina
* Enhanced balance and coordination
* Reduced pain and inflammation
* Improved cardiovascular health
* Increased range of motion and joint mobility
* Better overall physical functioning and quality of life.

Exercise therapy is typically prescribed and supervised by a healthcare professional, such as a physical therapist or exercise physiologist, who has experience working with individuals with similar medical conditions. The healthcare professional will create an individualized exercise program based on the patient's needs and goals, and will provide guidance and support to ensure that the exercises are performed safely and effectively.

Dexmedetomidine is a medication that belongs to a class of drugs called alpha-2 adrenergic agonists. It is used for sedation and analgesia (pain relief) in critically ill patients, as well as for procedural sedation in adults and children. Dexmedetomidine works by mimicking the effects of natural chemicals in the body that help to regulate sleep, wakefulness, and pain perception.

The medical definition of dexmedetomidine is: "A selective alpha-2 adrenergic agonist used for sedation and analgesia in critically ill patients, as well as for procedural sedation in adults and children. Dexmedetomidine has sedative, anxiolytic, analgesic, and sympatholytic properties, and its effects are mediated by activation of alpha-2 adrenergic receptors in the central nervous system."

It is important to note that dexmedetomidine should only be administered under the close supervision of a healthcare professional, as it can have significant effects on heart rate, blood pressure, and respiratory function.

Heat-related illnesses, also known as heat stress disorders, encompass a range of medical conditions that occur when the body is unable to cool down properly in hot environments. These conditions can vary in severity from mild heat rash or cramps to more serious and potentially life-threatening conditions such as heat exhaustion and heat stroke.

Heat rash, also known as prickly heat, is a skin irritation caused by excessive sweating during hot, humid weather. It typically occurs on the neck, chest, and thighs and appears as small red bumps or blisters.

Heat cramps are painful muscle spasms that can occur during or after intense physical activity in hot weather. They are often accompanied by heavy sweating and are most common in the legs, arms, and abdomen.

Heat exhaustion is a more severe form of heat-related illness that occurs when the body loses too much water and salt through excessive sweating. Symptoms may include weakness, dizziness, headache, nausea, vomiting, and fainting. If left untreated, heat exhaustion can lead to heat stroke.

Heat stroke is a medical emergency that occurs when the body's core temperature rises above 104°F (40°C) due to prolonged exposure to high temperatures or strenuous physical activity in hot weather. Symptoms may include confusion, seizures, loss of consciousness, and even death if not treated promptly.

Prevention measures for heat-related illnesses include staying hydrated, wearing loose-fitting clothing, taking frequent breaks during physical activity, avoiding prolonged exposure to the sun, and seeking air-conditioned environments when possible.

Fibrosis is a pathological process characterized by the excessive accumulation and/or altered deposition of extracellular matrix components, particularly collagen, in various tissues and organs. This results in the formation of fibrous scar tissue that can impair organ function and structure. Fibrosis can occur as a result of chronic inflammation, tissue injury, or abnormal repair mechanisms, and it is a common feature of many diseases, including liver cirrhosis, lung fibrosis, heart failure, and kidney disease.

In medical terms, fibrosis is defined as:

"The process of producing scar tissue (consisting of collagen) in response to injury or chronic inflammation in normal connective tissue. This can lead to the thickening and stiffening of affected tissues and organs, impairing their function."

Blood glucose, also known as blood sugar, is the concentration of glucose in the blood. Glucose is a simple sugar that serves as the main source of energy for the body's cells. It is carried to each cell through the bloodstream and is absorbed into the cells with the help of insulin, a hormone produced by the pancreas.

The normal range for blood glucose levels in humans is typically between 70 and 130 milligrams per deciliter (mg/dL) when fasting, and less than 180 mg/dL after meals. Levels that are consistently higher than this may indicate diabetes or other metabolic disorders.

Blood glucose levels can be measured through a variety of methods, including fingerstick blood tests, continuous glucose monitoring systems, and laboratory tests. Regular monitoring of blood glucose levels is important for people with diabetes to help manage their condition and prevent complications.

Hydrocortisone is a synthetic glucocorticoid, which is a class of steroid hormones. It is identical to the naturally occurring cortisol, a hormone produced by the adrenal gland that helps regulate metabolism and helps your body respond to stress. Hydrocortisone has anti-inflammatory effects and is used to treat various inflammatory conditions such as allergies, skin disorders, and autoimmune diseases. It works by suppressing the immune system's response to reduce swelling, redness, itching, and other symptoms caused by inflammation.

Hydrocortisone is available in different forms, including oral tablets, topical creams, lotions, gels, and ointments, as well as injectable solutions. The specific use and dosage depend on the condition being treated and the individual patient's medical history and current health status.

As with any medication, hydrocortisone can have side effects, especially when used in high doses or for extended periods. Common side effects include increased appetite, weight gain, mood changes, insomnia, and skin thinning. Long-term use of hydrocortisone may also increase the risk of developing osteoporosis, diabetes, cataracts, and other health problems. Therefore, it is essential to follow your healthcare provider's instructions carefully when using this medication.

Nitric Oxide Synthase (NOS) is a group of enzymes that catalyze the production of nitric oxide (NO) from L-arginine. There are three distinct isoforms of NOS, each with different expression patterns and functions:

1. Neuronal Nitric Oxide Synthase (nNOS or NOS1): This isoform is primarily expressed in the nervous system and plays a role in neurotransmission, synaptic plasticity, and learning and memory processes.
2. Inducible Nitric Oxide Synthase (iNOS or NOS2): This isoform is induced by various stimuli such as cytokines, lipopolysaccharides, and hypoxia in a variety of cells including immune cells, endothelial cells, and smooth muscle cells. iNOS produces large amounts of NO, which functions as a potent effector molecule in the immune response, particularly in the defense against microbial pathogens.
3. Endothelial Nitric Oxide Synthase (eNOS or NOS3): This isoform is constitutively expressed in endothelial cells and produces low levels of NO that play a crucial role in maintaining vascular homeostasis by regulating vasodilation, inhibiting platelet aggregation, and preventing smooth muscle cell proliferation.

Overall, NOS plays an essential role in various physiological processes, including neurotransmission, immune response, cardiovascular function, and respiratory regulation. Dysregulation of NOS activity has been implicated in several pathological conditions such as hypertension, atherosclerosis, neurodegenerative diseases, and inflammatory disorders.

Methoxamine is a synthetic, selective α1-adrenergic receptor agonist used in scientific research and for therapeutic purposes. It has the ability to stimulate the α1 adrenergic receptors, leading to vasoconstriction (constriction of blood vessels), increased blood pressure, and reduced blood flow to the skin and extremities.

In a medical context, methoxamine is primarily used as an experimental drug or in research settings due to its specific pharmacological properties. It may be employed to investigate the role of α1-adrenergic receptors in various physiological processes or to temporarily counteract the hypotensive (low blood pressure) effects of certain medications, such as vasodilators or anesthetics.

It is important to note that methoxamine is not commonly used in routine clinical practice due to its strong vasoconstrictive properties and potential adverse effects on organ function if misused or improperly dosed.

Right atrial function refers to the role and performance of the right atrium in the heart. The right atrium is one of the four chambers of the heart and is responsible for receiving deoxygenated blood from the body via the superior and inferior vena cava. It then contracts to help pump the blood into the right ventricle, which subsequently sends it to the lungs for oxygenation.

Right atrial function can be assessed through various methods, including echocardiography, cardiac magnetic resonance imaging (MRI), and electrocardiogram (ECG). Abnormalities in right atrial function may indicate underlying heart conditions such as right-sided heart failure, atrial fibrillation, or other cardiovascular diseases. Proper evaluation and monitoring of right atrial function are essential for effective diagnosis, treatment, and management of these conditions.

Survival analysis is a branch of statistics that deals with the analysis of time to event data. It is used to estimate the time it takes for a certain event of interest to occur, such as death, disease recurrence, or treatment failure. The event of interest is called the "failure" event, and survival analysis estimates the probability of not experiencing the failure event until a certain point in time, also known as the "survival" probability.

Survival analysis can provide important information about the effectiveness of treatments, the prognosis of patients, and the identification of risk factors associated with the event of interest. It can handle censored data, which is common in medical research where some participants may drop out or be lost to follow-up before the event of interest occurs.

Survival analysis typically involves estimating the survival function, which describes the probability of surviving beyond a certain time point, as well as hazard functions, which describe the instantaneous rate of failure at a given time point. Other important concepts in survival analysis include median survival times, restricted mean survival times, and various statistical tests to compare survival curves between groups.

Blood gas analysis is a medical test that measures the levels of oxygen and carbon dioxide in the blood, as well as the pH level, which indicates the acidity or alkalinity of the blood. This test is often used to evaluate lung function, respiratory disorders, and acid-base balance in the body. It can also be used to monitor the effectiveness of treatments for conditions such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory illnesses. The analysis is typically performed on a sample of arterial blood, although venous blood may also be used in some cases.

Pregnancy is a physiological state or condition where a fertilized egg (zygote) successfully implants and grows in the uterus of a woman, leading to the development of an embryo and finally a fetus. This process typically spans approximately 40 weeks, divided into three trimesters, and culminates in childbirth. Throughout this period, numerous hormonal and physical changes occur to support the growing offspring, including uterine enlargement, breast development, and various maternal adaptations to ensure the fetus's optimal growth and well-being.

Epidural anesthesia is a type of regional anesthesia that involves the injection of local anesthetic medication into the epidural space in the spine, which is the space surrounding the dura mater, a membrane that covers the spinal cord. The injection is typically administered through a catheter placed in the lower back using a needle.

The local anesthetic drug blocks nerve impulses from the affected area, numbing it and relieving pain. Epidural anesthesia can be used for various surgical procedures, such as cesarean sections, knee or hip replacements, and hernia repairs. It is also commonly used during childbirth to provide pain relief during labor and delivery.

The effects of epidural anesthesia can vary depending on the dose and type of medication used, as well as the individual's response to the drug. The anesthetic may take several minutes to start working, and its duration of action can range from a few hours to a day or more. Epidural anesthesia is generally considered safe when administered by trained medical professionals, but like any medical procedure, it carries some risks, including infection, bleeding, nerve damage, and respiratory depression.

Hexamethonium is defined as a ganglionic blocker, which is a type of medication that blocks the activity at the junction between two nerve cells (neurons) called the neurotransmitter receptor site. It is a non-depolarizing neuromuscular blocking agent, which means it works by binding to and inhibiting the action of the nicotinic acetylcholine receptors at the motor endplate, where the nerve meets the muscle.

Hexamethonium was historically used in anesthesia practice as a adjunct to provide muscle relaxation during surgical procedures. However, its use has largely been replaced by other neuromuscular blocking agents that have a faster onset and shorter duration of action. It is still used in research settings to study the autonomic nervous system and for the treatment of hypertensive emergencies in some cases.

It's important to note that the use of Hexamethonium requires careful monitoring and management, as it can have significant effects on cardiovascular function and other body systems.

Pulmonary circulation refers to the process of blood flow through the lungs, where blood picks up oxygen and releases carbon dioxide. This is a vital part of the overall circulatory system, which delivers nutrients and oxygen to the body's cells while removing waste products like carbon dioxide.

In pulmonary circulation, deoxygenated blood from the systemic circulation returns to the right atrium of the heart via the superior and inferior vena cava. The blood then moves into the right ventricle through the tricuspid valve and gets pumped into the pulmonary artery when the right ventricle contracts.

The pulmonary artery divides into smaller vessels called arterioles, which further branch into a vast network of tiny capillaries in the lungs. Here, oxygen from the alveoli diffuses into the blood, binding to hemoglobin in red blood cells, while carbon dioxide leaves the blood and is exhaled through the nose or mouth.

The now oxygenated blood collects in venules, which merge to form pulmonary veins. These veins transport the oxygen-rich blood back to the left atrium of the heart, where it enters the systemic circulation once again. This continuous cycle enables the body's cells to receive the necessary oxygen and nutrients for proper functioning while disposing of waste products.

Heart valve prosthesis implantation is a surgical procedure where an artificial heart valve is inserted to replace a damaged or malfunctioning native heart valve. This can be necessary for patients with valvular heart disease, including stenosis (narrowing) or regurgitation (leaking), who do not respond to medical management and are at risk of heart failure or other complications.

There are two main types of artificial heart valves used in prosthesis implantation: mechanical valves and biological valves. Mechanical valves are made of synthetic materials, such as carbon and metal, and can last a long time but require lifelong anticoagulation therapy to prevent blood clots from forming. Biological valves, on the other hand, are made from animal or human tissue and typically do not require anticoagulation therapy but may have a limited lifespan and may need to be replaced in the future.

The decision to undergo heart valve prosthesis implantation is based on several factors, including the patient's age, overall health, type and severity of valvular disease, and personal preferences. The procedure can be performed through traditional open-heart surgery or minimally invasive techniques, such as robotic-assisted surgery or transcatheter aortic valve replacement (TAVR). Recovery time varies depending on the approach used and individual patient factors.

Ephedrine is a medication that stimulates the nervous system and is used to treat low blood pressure, asthma, and nasal congestion. It works by narrowing the blood vessels and increasing heart rate, which can help to increase blood pressure and open up the airways in the lungs. Ephedrine may also be used as a bronchodilator to treat COPD (chronic obstructive pulmonary disease).

Ephedrine is available in various forms, including tablets, capsules, and solutions for injection. It is important to follow the instructions of a healthcare provider when taking ephedrine, as it can have side effects such as rapid heart rate, anxiety, headache, and dizziness. Ephedrine should not be used by people with certain medical conditions, such as heart disease, high blood pressure, or narrow-angle glaucoma, and it should not be taken during pregnancy or breastfeeding without consulting a healthcare provider.

In addition to its medical uses, ephedrine has been used as a performance-enhancing drug and is banned by many sports organizations. It can also be found in some over-the-counter cold and allergy medications, although these products are required to carry warnings about the potential for misuse and addiction.

For healthy people, the Target Heart Rate (THR) or Training Heart Rate Range (THRR) is a desired range of heart rate reached ... The American Heart Association states the normal resting adult human heart rate is 60-100 bpm. Tachycardia is a high heart rate ... Heart rate reserve (HRreserve) is the difference between a person's measured or predicted maximum heart rate and resting heart ... "All About Heart Rate (Pulse)". All About Heart Rate (Pulse). American Heart Association. 22 Aug 2017. Retrieved 25 Jan 2018. " ...
... (HRT) is a baroreflex-mediated adjustment of heart rate which acts as a counter-mechanism to premature ... that heart rate then slows down beyond what it was before the PVC, before returning to the original heart rate. Schmidt ... "Heart rate turbulence predicts all-cause mortality and sudden death in congestive heart failure patients". Heart Rhythm. 5 (8 ... Heart rate variability Cygankiewicz, Iwona (2013). "Heart rate turbulence". Progress in Cardiovascular Diseases. 56 (2): 160- ...
The parasympathetic nervous system works to decrease heart rate, while the SNS works to increase heart rate, and this is ... Billman GE (2013). "The effect of heart rate on the heart rate variability response to autonomic interventions". Frontiers in ... "Should heart rate variability be "corrected" for heart rate? Biological, quantitative, and interpretive considerations". ... re-examining a widely used heart rate variability measure". Heart. 88 (4): 378-380. doi:10.1136/heart.88.4.378. PMC 1767394. ...
A heart rate monitor (HRM) is a personal monitoring device that allows one to measure/display heart rate in real time or record ... Most companies use their own proprietary heart rate algorithms. The newer, wrist based heart rate monitors have achieved almost ... Both types of signals can provide the same basic heart rate data, using fully automated algorithms to measure heart rate, such ... Modern heart rate monitors commonly use one of two different methods to record heart signals (electrical and optical). ...
... increased heart rate. It is a common misconception and pure speculation that atelectasis causes fever. A study of 100 post-op ... This is a frequent occurrence with pleural effusion, caused by congestive heart failure (CHF). Leakage of air into the pleural ... heart and mediastinum; displacement of the hilus and shifting granulomas. Atelectasis may be an acute or chronic condition. In ...
Electrophysiology QRS Heart rate Heart rate variability Affective computing Pan, Jiapu; Tompkins, Willis J. (March 1985). "A ... This feature makes it particularly suitable for measuring heart rate, the first way to assess the heart health state. In the ... The HR is often used to compute the heart rate variability (HRV) a measure of the variability of the time interval between ... Task Force of the European Society Electrophysiology (March 1996). "Heart Rate Variability". Circulation. 93 (5): 1043-1065. ...
1.5, base deficit >=6, heart rate >= 120 bpm, presence of penetrating trauma, and positive Focused Abdominal Sonography Trauma ... Data would suggest that the longer the abdomen is left open from initial laparotomy the higher the rate of complications. After ... morbidity rate. There are four main complications. The first is development of an intra-abdominal abscess. This has been ... benefit in mortality Recently there has been further data in trauma patients that has demonstrated increased survival rates [ ...
Heart rate exploding]. Star News. Retrieved 2021-06-13. Park, Seo-yeon (June 11, 2021). 비투비, 13일 디지털 싱글 'Blue Moon' 발매..깊어진 재즈 ...
... that utilizes the green LED lights to measure heart rates. To gauge a user's heart rate, the watch flashes green light from the ... the amounts of each type of reflected light are compared to determine heart rate. The Watch adjusts the sampling rate and LED ... "Your heart rate. What it means, and where on Apple Watch you'll find it". Apple Inc. May 30, 2015. Archived from the original ... "Your heart rate. What it means, and where on Apple Watch you'll find it.", Apple Support (in German), archived from the ...
"Tachycardia , Fast Heart Rate". American Heart Association. Archived from the original on 12 April 2013. Retrieved 19 April ... Outcomes are generally good in those who otherwise have a normal heart. An ultrasound of the heart may be done to rule out ... Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast heart rhythm typically between ... conducted to the heart by the vagus nerve. These manipulations are collectively referred to as vagal maneuvers.[citation needed ...
"Lowest heart rate". Guinness World Records. Retrieved 21 October 2015. "Glasgow 2014: Guernsey runner Tom Druce retires from ... world record holder of the slowest heart ever recorded in a healthy human Lee Luscombe (born 1971), footballer; played for ...
Heart Rate, and Autonomic Modulation of Heart Rate in Men and Women with Hypertension. L. P.T. Hua, C. A. Brown, S. J.M. Hains ... heart rate, HR; beats per minute, BPM; heart rate variability, HRV; vasomotor activity), muscle activity (electromyography, EMG ... Heart Rate Variability Standards of Measurement, Physiological Interpretation, and Clinical Use. Circulation. 1996:1043-1065. ... Physiological responses also can be measured via instruments that read bodily events such as heart rate change, electrodermal ...
... both heart rate and respiration rate decrease; judgment becomes impaired as drowsiness supervenes, becoming steadily deeper ... Blood that is too warm produces dyspnea by exhausting the metabolic capital of the respiratory centre; heart rate is increased ... However, too high a temperature speeds up the metabolism of different tissues to such a rate that their metabolic capital is ... Most body heat is generated in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles ...
... to lower heart rate. The cardiovascular centre also increases the stroke volume of the heart (that is, the amount of blood it ... This increases heart rate. Many anaesthetics depress the activity of the cardiovascular center. Phencyclidine may be a useful ... The cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via two sets of ... The cardiovascular centre is a part of the human brain which regulates heart rate through the nervous and endocrine systems. It ...
Heart rate variability (HRV). Detection theory in hearing and vision. Sigma Xi (1968). IEEE Browder J. Thompson Memorial Prize ... Teich, Malvin C.; Lowen, Steven B.; Jost, Bradley M.; Vibe-Rheymer, Karin; Heneghan, Conor (2001). "Heart Rate Variability: ... Teich, Malvin Carl (September 2005). Heart Rate Variability (PDF) (Speech). Workshop on New Themes and Techniques in Complex ... Lowen, Steven B.; Cash, Sydney S.; Poo, Mu-ming; Teich, Malvin C. (1 August 1997). "Quantal Neurotransmitter Secretion Rate ...
Heart rate variability studies. Wavelet analysis. Automatic detection of epileptic activity in electroencephalograms using ... the first artificial heart was implanted in a calf. Between 1980 and 1982 sixteen more hearts were implanted in calves. At the ... The artificial heart project was then abandoned due to excessive costs. Nevertheless, the acquired equipment made many basic ... Alberto Crotoggini, Juan Barra, Pichel and Willshaw made important contributions to the comprehension of heart and circulatory ...
... monitoring heart rate and breathing; heart rate variability detection; fall detection; recognizing and counting people in ... Su, W.; Safar, Z.; Liu, K.J.R. (Jan 2005). "Full-Rate Full-Diversity Space-Frequency Codes with Optimum Coding Advantage". IEEE ... With that his group developed the world's first full-diversity, full-rate space-frequency code and the only available ...
His heart rate dropped ... leading to his death from a cardiac arrest ... a classic secondary response to raised intercranial ... Berati ... was struck from behind .... also kicked and had a rock dropped on his head, before dying of heart failure while ...
The functions of a Holter monitor captures and records information such as heart rates during day and night, abnormal heart ... 1952 Artificial heart An artificial heart is implanted into the body to replace the biological heart. On July 3, 1952, 41-year- ... Fetal heart rate monitoring. Lippincott Williams & Wilkins. 2003. ISBN 9780781735247. "Ty-Rap Celebrates 50 Years!". THOMAS & ... The Jarvik heart was not banned for permanent use. Since 1982, more than 350 people have received the Jarvik heart as a bridge ...
A saltatory pattern of fetal heart rate is defined in cardiotocography (CTG) guidelines by FIGO as fetal heart rate (FHR) ... with one above the fetal heart to monitor heart rate, and the other at the fundus of the uterus to measure frequency of ... The fetal heart rate and the activity of the uterine muscle are detected by two transducers placed on the mother's abdomen, ... Combined with an internal fetal monitor, an IUPC may give a more precise reading of the baby's heart rate and the strength of ...
and changes in heart rate; 2) benign dysfunctions and trivial, self-limited infirmities such as transient tinnitis, a twitching ...
"Rare heart disease rate doubles". BBC. 17 June 2002. Archived from the original on 26 May 2004. Rutter, Megan (20 April 2020 ... Heart complications are the most important aspect of Kawasaki disease, which is the leading cause of heart disease acquired in ... are often observed in the acute phase of Kawasaki disease due to inflammation of the heart valve or inflammation of the heart ... In Japan, the rate is 240 in every 100,000 people. Coronary artery aneurysms due to Kawasaki disease are believed to account ...
Positive chronotropes increase heart rate; negative chronotropes decrease heart rate. A dromotrope affects atrioventricular ... are those that change the heart rate. Chronotropic drugs may change the heart rate and rhythm by affecting the electrical ... conduction system of the heart and the nerves that influence it, such as by changing the rhythm produced by the sinoatrial node ...
When generated, insight reports aggregate heart rate measurements over a one-month period. Users can see their heart rate ... "Smart-Phone App Tracks Heart Rate". Technology Review. Retrieved May 26, 2018. "Instant Heart Rate by Azumio". azumio.com. ... On February 23, 2019, The Wall Street Journal reported that the health-oriented app owned by Azumio, "Instant Heart Rate: HR ... With advancements in mobile phone camera resolution, most smart phones can accurately measure heart rate by analyzing minute ...
2012). Fetal Heart Rate Monitoring. Lippincott Williams & Wilkins. p. 1. ISBN 978-1451171709. Rothman, Barbara Katz (1993). ... With a maternal mortality rate about one-quarter of the national average, DeLee's Chicago Lying-In Hospital became well- ...
The adult resting heart rate ranges from 60 to 100 bpm. The resting heart rate of a newborn can be 129 beats per minute (bpm) ... An athlete's heart rate can be lower than 60 bpm. During exercise the rate can be 150 bpm with maximum rates reaching from 200 ... In a healthy heart blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in ... with a heart rate of 186 BPM. Problems playing this file? See media help. The normal resting heart rate is called the sinus ...
Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems. 28 °C (82.4 °F) - Severe heart rhythm ... Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may suffer ... There is the possibility of heart irritability. 34 °C (93.2 °F) - Severe shivering, loss of movement of fingers, blueness, and ... Temperature examination in the heart, using a catheter, is the traditional gold standard measurement used to estimate core ...
... heart rate and rhythm disorders." Canadian adverse reactions newsletter. Government of Canada. January 2007 17(1) "De Standaard ... However, increased rate of gastric emptying induced by drugs like domperidone does not always correlate well with relief of ...
Monitoring of heart rate is the best indicator of response to resuscitation efforts. Epinephrine should be administered ... All infants who are 'gasping', show signs of being apnoeic (suspension of breathing), or have bradycardia with a heart rate ... Intravenous epinephrine is administered if the heart rate does not increase to 60 beats per minute after ventilation and chest ... Johnson, Peter A.; Schmölzer, Georg M. (23 February 2020). "Heart Rate Assessment during Neonatal Resuscitation". Healthcare. 8 ...
"Ambient pollution and heart rate variability". Circulation. 101 (11): 1267-1273. doi:10.1161/01.cir.101.11.1267. PMID 10725286 ... the mechanism presented allows to establish the rate observed experimentally, with a rate constant (Kobs) and corresponding to ... The reaction rate laws for every step are the ones that follow: V 1 = K 1 ⋅ [ O 3 ] V 2 = K 2 ⋅ [ O ] ⋅ [ O 3 ] {\displaystyle ... Humidity control can vastly improve both the killing power of the ozone and the rate at which it decays back to oxygen (more ...
... maximum or target heart rate with our simple chart and learn how exercise intensity can affect heart rate, losing weight and ... ask your healthcare provider what your heart rate should be.. What if my heart rate is too high or too low?. If your heart rate ... Maximum and Target Heart Rate by Age. This table shows target heart rate zones for different ages. Your maximum heart rate is ... What is a resting heart rate?. Your resting heart rate is the number of times your heart beats per minute when youre at rest. ...
For healthy people, the Target Heart Rate (THR) or Training Heart Rate Range (THRR) is a desired range of heart rate reached ... The American Heart Association states the normal resting adult human heart rate is 60-100 bpm. Tachycardia is a high heart rate ... Heart rate reserve (HRreserve) is the difference between a persons measured or predicted maximum heart rate and resting heart ... "All About Heart Rate (Pulse)". All About Heart Rate (Pulse). American Heart Association. 22 Aug 2017. Retrieved 25 Jan 2018. " ...
Shop for heart rate scales at Best Buy. Find low everyday prices and buy online for delivery or in-store pick-up. ... heart rate scales. .. Heart rate scales are used to measure heart rate. They are often used by athletes to track their heart ... exercise heart rates. "I cant turn he broadcast for pulse rate on while I am doing a workout, so I cannot follow the heartrate ... heart rate gps running watch. "love the heart rate monitor. hard to learn how to use, wish it came with a paper manual" ...
Sacred Heart University is a University located in Fairfield, CT . ... Sacred Heart University is a University institution located in Fairfield, CT, in a suburban setting. ... Interested in Sacred Heart University? Admissions officers are waiting to hear from you! ...
... resting heart rate, active heart rate, various sleep scores, and breathing rate (and, of course, a manually entered early ... Could the heart rate variability (HRV) score come to be thought of similarly? Much as the sed rate and CRP are sensitivity ... Cite this: Heart Rate Variability: Are We Ignoring a Harbinger of Health? - Medscape - Oct 25, 2023. ... I even check my "readiness score" (a calculation using resting heart rate, recent sleep, recent active zone minutes, and ...
Symptoms and signs of High Blood Pressure And Rapid Heart Rate (Pulse) and their most common related conditions. ... High blood pressure with rapid heart rate can be seen with panic attack, anxiety, PTSD, stress reaction, hypertension, stroke, ... High Blood Pressure And Rapid Heart Rate (Pulse). *Medical Author: Sabrina Felson, MD ... A person experiencing a panic attack may believe that he or she is having a heart attack or that death is imminent. The fear ...
Read on to learn more about heart rate, including normal resting heart rates, target heart rates with exercise, and abnormal ... What is a resting heart rate and what are the normal values for an adult? ... Whats an unhealthy heart rate?. The typical resting heart rate for adults is between 60-100 beats per minute (bpm). Some ... While the heart rate increases as a result of physical activity, an overall decrease in target heart rate is possible over time ...
Check out the ACTIVE Reviews Teams top-rated heart rate monitors. ... The best heart rate monitor can help you track how intensely youre working out. ... Best Heart Rate Monitor for Runners: Polar H10 Heart Rate Sensor * Best Heart Rate Monitor for Triathlons: Polar H9 Heart Rate ... Best Value Heart Rate Monitor: CooSpo H6 Heart Rate Monitor * Best Heart Rate Monitor Battery Life: Amazfit Band 5 Activity ...
People who have the condition have irregular heartbeat and could suffer from stroke, blood clots and heart failure. ... The Stanford researchers that conducted Apples Heart Study have published their paper in the New England Journal of Medicine. ... Stanford publishes its massive Apple Watch heart-rate study. The paper is published in the New England Journal of Medicine.. ... The Heart Study app monitored the participants heart rhythm to look for the presence of an irregular pulse. Researchers sent ...
... Eur Heart J. 2006 Oct;27(20):2387-93. doi: 10.1093/eurheartj/ehl259. Epub 2006 ...
One way of monitoring physical activity intensity is to determine whether a persons pulse or heart rate is within the target ... your target heart rate should be between 64% and 76%1,2 of your maximum heart rate. You can estimate your maximum heart rate ... For vigorous-intensity physical activity, your target heart rate should be between 77% and 93%1,2 of your maximum heart rate. ... Target Heart Rate and Estimated Maximum Heart Rate. ... To estimate your maximum age-related heart rate, subtract your ...
... recovery heart rate, and that rate will go down as you become more fit. The actual numbers vary because everyones heart rate ... Your heart rate slows down when you stop exercising. Your pulse two minutes after exercise is what is called your ... recovery heart rate, and that rate will go down as you become more fit. The actual numbers vary because everyones heart rate ... The heart rate of a typical individual will return to resting levels shortly after light or moderate exercise.The heart rates ...
For those not familiar with it, it is the difference between your maximum heart rate and your resting heart rate. In my case, I ... I dont have a specific question on the topic of Heart Rate Reserve (HRR) but was interested in having a discussion about it. ... Heart Rate Reserve I dont have a specific question on the topic of Heart Rate Reserve (HRR) but was interested in having a ... For those not familiar with it, it is the difference between your maximum heart rate and your resting heart rate.. In my case, ...
Heart Disease Rates by Country. Poor lifestyle choices and genetic factors place many people at high risk for life threatening ... The standard mortality rate due to CVD in Russia is also the highest among all of the developed nations of the world. One might ... Heart disease is the worlds leading cause of death, accounting for 15.5% of all deaths worldwide. Here is a list of countries ... There is also a huge regional difference in the death rates due to CVD in Russia, with the maximum number of such deaths taking ...
... and learn more about Resting Heart Rate. Download Resting Heart Rate and enjoy it on your iPhone, iPad, and iPod touch. ... Resting Heart Rate 12+ Track your resting heart rate ASSIC MEDICAL (Pty) Ltd Designed for iPhone * *Free ... ASSIC Resting heart rate(HR) allows for the measure of baseline heart rate required for the body to maintain efficient blood ... and the rate of delivery which is dependent on the HR (number of heart beats per minute).. By increasing the blood volume ( ...
4,145 heart rate monitor icons. Vector icons in SVG, PSD, PNG, EPS and ICON FONT ...
... such as elevated resting heart rates or slower heart rate recovery after exercising. Ballinger says monitoring heart rate ... If we can start extrapolating the heart-rate data from Apple Watch to detect ailments that arent specific to the heart, ... Weve heard numerous stories of how Apple Watchs heart rate sensor has saved people from heart attacks and pulmonary embolisms ... "The heart rate sensor that you wear already from the Apple Watch may actually be able to detect signs of diabetes," Cardiogram ...
Stroke Hospitalization Rates for Blacks Aged 65 Years and Older by County ... Geographic Patterns: Heart Disease Hospitalization Rates for 2018 through 2020 for Blacks Aged 65 Years and Older by County. ... The map shows that pockets of counties with high heart disease hospitalization rates - meaning the top quintile - are located ... View this map within the Interactive Atlas of Heart Disease and Stroke so that you can add additional information to the map or ...
... exposure to high levels of traffic-related air pollutants is linked to reduced heart rate variability (HRV) ... In patients with pre-existing heart or lung disease, ... Heart Attack. Heart attack is the death of the heart muscle due ... Congenital Heart Disease. Heart diseases that are present at birth are called " Congenital heart diseases". ... Reduced Heart Rate Variability Caused by Air Pollution Personalised Printable Document (PDF). Please complete this form and ...
"Using Heart-Rate Zones to Burn Fat"}}> Using Heart-Rate Zones to Burn Fat Learn how this fat-burning range breaks down into ... Heart Rate Zones. <. >", "path": "https://www.betternutrition.com/conditions-and-wellness/using-heart-rate-zones-to-burn-fat ... www.betternutrition.com/conditions-and-wellness/using-heart-rate-zones-to-burn-fat/", "listing_type": "archive", "location": " ... three specific heart-rate zones, the benefits of each and how to calculate them. ...
... heart rate - Sharing our stories on preparing for and responding to public health events ...
Thereby heart rate is computed cycle by cycle. With the BPM measurement saved as a channel in the graph, the heart rate is ... Computing heart rate 13889 - 0 is_singleHome , Knowledge Base , Computing heart rate ... NOT the average heart rate over the selected segment. To obtain an average heart rate, use a "Mean" measurement on a channel ... The algorithm used to derive rates via "Find Rate" or "Rate" calculation channels is extensively documented in Application Note ...
Heart Rate Estimation from Video Changes to skin color due to blood flow in the skin can be captured on video and used to find ... Heart Rate Estimation from Video » Measuring Car Velocity via Acoustic Doppler Effect » Generate Sound from an Image ( ... an estimate of heart rate. Although such a change is too small to be seen by the human eye, the signal can be nicely extracted ...
FiTrainer is an interesting product that combines headphones and a heart beat meter into one convenient unit. Featuring an ear ... FiTrainer Automatic Heart Rate Monitor Helps With Exercise. April 7th, 2009 Medgadget Editors Sports Medicine ... FiTrainer is an interesting product that combines headphones and a heart beat meter into one convenient unit. Featuring an ear ... clip that detects ones heart rhythm, the system notifies the user of the current number via voice inside the headphones, which ...
Resting heart rate, temporal changes in resting heart rate, and overall and cause-specific mortality ... Resting heart rate (RHR) is a clinical parameter easily measurable with typical value between 50 and 90 beats per minute (bpm) ... Heart 2017; 104 1076-1085 Published Online First: 21 Dec 2017. doi: 10.1136/heartjnl-2017-312251 ...
... risk of suffering a major cardiovascular event can be measured by their resting heart rate. ... A new study finds that heart disease patients ... As opposed to a high heart rate, which can affect heart muscle ... the heart rate increases. To reduce the amount of stress alcohol puts on the heart, the American Heart Association suggests ... The study found that heart disease patients with baseline heart rates of over 70 beats per minute had a 39 percent increased ...
"Then his heart rate rapidly decreases after hes got the go to stay-we can see a rapid drop-off, where his comfort level ... And yet their heart rates during the launch stayed reasonably normal: Armstrongs was the highest, at 110 beats per minute, ... This chart of Armstrongs heart rate is in the biomedical section of the Apollo 11 Mission Report. NASA. "The adrenaline, fight ... Those heart rate figures are what aerospace experts would expect to see for experienced, physically fit astronauts enduring the ...
Right From The Heart Ministries has earned a 4/4 Star rating on Charity Navigator. This Religious Organization is headquartered ... Rating Information. Great. This charitys score is 100%, earning it a Four-Star rating. If this organization aligns with your ... In 1992, Right From The Heart Ministries began in the heart of Bryant Wright, Senior Pastor of Johnson Ferry Baptist Church in ... In 1992, Right From The Heart Ministries began in the heart of Bryant Wright, Senior Pastor of Johnson Ferry Baptist Church in ...
Smoking and alcohol consumption raises the lifetime risk of rapid and irregular heart rate, leading to several diseases. ... Smoking and alcohol consumption increases lifetime risk of a rapid and irregular heart rate, called atrial fibrillation, which ... Smoking, Alcohol Consumption Increase Lifetime Risk Of Irregular Heart Rate Personalised Printable Document (PDF). Please ... Alcohol consumption and smoking can increase the risk of irregular heart rate. ...
  • Heart Rate Variability: Ignoring a Harbinger of Health? (medscape.com)
  • Could the heart rate variability (HRV) score come to be thought of similarly? (medscape.com)
  • Welltory analyzes heart rate variability (hrv) - a heart health marker backed by over 25,000 studies on PubMed. (google.com)
  • Our symptom tracker uses heart rate variability to analyze your disease symptoms. (google.com)
  • Not only can a heart rate monitor help you reach your target intensity level , and track your heart rate variability but it can also help you be vigilant against overexertion and over-training. (active.com)
  • DeepHeart is able to monitor the pattern of beat to beat heart rate variability to detect changes that are associated with diabetes, such as elevated resting heart rates or slower heart rate recovery after exercising. (macworld.com)
  • Ballinger says monitoring heart rate variability can predict whether someone is likely to develop diabetes, so DeepHeart is "actually detecting the early stages of that disease before it detects a severe complication. (macworld.com)
  • In patients with pre-existing heart or lung disease, exposure to high levels of traffic-related air pollutants is linked to reduced heart rate variability (HRV) - a risk factor for sudden cardiac death, a new study hasfound. (medindia.net)
  • A study by Oak Ridge National Laboratory and partners might help explain whether there is a relationship between inhalation of small particles, reduced heart rate variability and death. (news-medical.net)
  • While there is evidence to suggest that breathing air containing particulate matter can cause problems for people with decreased heart rate variability, no one has done a definitive study to examine whether there is a direct link between the two. (news-medical.net)
  • Understanding the relationship between heart rate variability and particle exposure could help explain increased mortality associated with inhalation of small particles," Jenkins said. (news-medical.net)
  • We hope this will be a first step toward learning how heart rate variability changes as we move through many environments during the course of a day. (news-medical.net)
  • Heart rate variability refers to the beat-to-beat alterations in heart rate on a micro-second time scale. (news-medical.net)
  • The big challenge -- and the only way to get a real handle on the problem -- is to simultaneously measure heart rate variability, respiration and particulate concentrations," said Jenkins, who has published several papers about real-world exposures to environmental tobacco smoke. (news-medical.net)
  • We should have a far better understanding of the mechanisms that control changes in heart rate variability associated with particulate exposure," Jenkins said. (news-medical.net)
  • And we should know what it will take to develop a portable real-time monitor that can simultaneously measure heart rate variability, respiration and airborne particle concentration. (news-medical.net)
  • Orthostatic test - Orthostatic test records your heart rate variability and equips you with knowledge about your recovery as well as tools to optimize your training. (probikekit.com)
  • Cardiac vagal tone (indexed via resting heart rate variability [HRV]) has been previously associated with superior executive functioning. (frontiersin.org)
  • Cardiac vagal tone, indexed via heart rate variability (HRV), is one prominent marker of such visceral functioning. (frontiersin.org)
  • The heart autonomic modulation can be measured noninvasively, this process is known the analysis of heart rate variability (HRV) 8 . (bvsalud.org)
  • There is strong evidence that obesity leads to increased sympathetic modulation and a decreased vagal tone leading to a lack of autonomic control (characterized by reduction of heart rate variability) that can bring about changes in the renin-angiotensin-aldosterone system in alpha agonists and central alpha 2-1 and beta-adrenergic receptors. (bvsalud.org)
  • High job burnout predicts low heart rate variability in the working population after a first episode of acute coronary syndrome. (cdc.gov)
  • Job burnout may affect the prognosis of patients with acute coronary syndrome (ACS) through mechanisms involving heart rate variability (HRV). (cdc.gov)
  • Your resting heart rate is the number of times your heart beats per minute when you're at rest. (heart.org)
  • An athlete or more active person may have a resting heart rate as low as 40 beats per minute. (heart.org)
  • Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions of the heart per minute (beats per minute, or bpm). (wikipedia.org)
  • The heart rate measures the number of times per minute that the heart contracts or beats. (medicalnewstoday.com)
  • For most adults, a target resting heart rate is between 60-100 beats per minute. (medicalnewstoday.com)
  • The heart rate is the number of times the heart beats in the space of a minute. (medicalnewstoday.com)
  • The normal resting heart rate for adults over the age of 10 years, including older adults, is between 60-100 beats per minute (bpm) . (medicalnewstoday.com)
  • A person's heart rate increases during exercise, as the heart beats more to pump more blood and oxygen throughout the body. (medicalnewstoday.com)
  • For example, for a 50-year-old person, the estimated maximum age-related heart rate would be calculated as 220 - 50 years = 170 beats per minute (bpm). (cdc.gov)
  • For example, for a 35-year-old person, the estimated maximum age-related heart rate would be calculated as 220 - 35 years = 185 beats per minute (bpm). (cdc.gov)
  • A healthy person should see his heart rate decline by 15 to 20 beats per minute in the first minute after stopping exercise. (livestrong.com)
  • Say you run for 30 minutes at an average heart rate of 155 beats per minute and your heart rate two minutes after finishing is 95 beats per minute. (livestrong.com)
  • Blood delivery to supply the body's demands is dependent on the volume of blood ejected by the heart (stroke volume) and the rate of delivery which is dependent on the HR (number of heart beats per minute). (apple.com)
  • All that said, heart beats or their after-effects are identified as some regular occurrence-typically of a positive peak-in the data. (biopac.com)
  • These event marks can then be edited so that noise that initially causes erroneous "beats" to be identified or legitimate beats to be missed will not compromise the computation of the heart rate. (biopac.com)
  • Resting heart rate (RHR) is a clinical parameter easily measurable with typical value between 50 and 90 beats per minute (bpm) that varies during the day with a night-time decrease. (bmj.com)
  • and a 65 percent increased risk of death from all causes compared to patients with the lowest heart rate-58 beats per minute or less. (qualityhealth.com)
  • Normally the heart beats between 60 and 100 times per minute. (qualityhealth.com)
  • And yet their heart rates during the launch stayed reasonably normal: Armstrong's was the highest, at 110 beats per minute, Collins' was 99, and Aldrin's a low 88. (popsci.com)
  • The dicey moon landing itself, as Armstrong manually flew the lunar lander, saw his heart rate climb up to 150 beats per minute, then come back down again in the seconds after they'd completed their historic touchdown. (popsci.com)
  • Yes, when you're involved in a romantic relationship, your heart beats as fast as your partner's. (nature.com)
  • And inspired from this study, here's a great line which may do wonders today of all days: "I love you so much that my heart beats as fast as yours whenever I see you. (nature.com)
  • In general, for adults, a resting heart rate of fewer than 60 beats per minute (BPM) qualifies as bradycardia. (goredforwomen.org)
  • FR70 continuously tracks heart beats per minute and displays your heart rate zone, so you can monitor and improve your fitness level. (woot.com)
  • A normal, resting heart rate for the average adult ranges from 60 to 100 beats per minute. (archbold.org)
  • According to calculations, the maximum heart rate you should have is around 220 beats per minute (bpm) minus your age. (archbold.org)
  • Your target heart rate minus five beats. (best-running-tips.com)
  • Target Heart Rate 1 minus and plus five beats. (best-running-tips.com)
  • Having various complications after surgery this App helped me when my heart rate went fast, skipped beats, paused and even during Bradycardia which subsequently needed a Pacemaker. (instantheartrate.com)
  • Blood pressure is the force of blood flowing against the walls of your arteries, while heart rate - sometimes called pulse - is the number of times your heart beats every minute. (clevelandclinic.org)
  • Optimal blood pressure typically is defined as 120 mm Hg systolic - which is the pressure as your heart beats - over 80 mm Hg diastolic - which is the pressure as your heart relaxes. (clevelandclinic.org)
  • For your resting heart rate, the target is between 60 and 100 beats per minute (BPM). (clevelandclinic.org)
  • Each 1°C increase in body temperature between 32.0°C and 42.0°C was associated with an 8.35 beats/min increase in heart rate. (lu.se)
  • CONCLUSIONS: Increase in body temperature is associated with a linear increase in heart rate of 9.46 beats/min/°C in female and 7.24 beats/min/°C in male patients. (lu.se)
  • It also may be heat stroke or heart arrhtymtia like atrial fibrillation . (medicinenet.com)
  • What the Apple Heart Study shows us is that atrial fibrillation is just the beginning. (engadget.com)
  • The mobile health data company's deep learning network, DeepHeart, already uses data from the Apple Watch ($429 on Apple.com ) heart rate sensor to detect atrial fibrillation , hypertension, and sleep apnea. (macworld.com)
  • We've heard numerous stories of how Apple Watch's heart rate sensor has saved people from heart attacks and pulmonary embolisms, and Cardiogram's research on atrial fibrillation last year ended up mirroring Apple's own study in watchOS 4. (macworld.com)
  • Last year, Cardiogram studied ways in which the Apple Watch could be used to detect atrial fibrillation, an ability Apple is also researching with its own Heart Study app. (macworld.com)
  • Smoking and alcohol consumption increases lifetime risk of a rapid and irregular heart rate, called atrial fibrillation, which can lead to a stroke, dementia, heart failure and other complications, a new study says. (medindia.net)
  • The researchers assessed 5,338 participants from the Framingham Heart Study who did not have atrial fibrillation at one or more of the index ages of 55, 65, and 75 years. (medindia.net)
  • Atrial fibrillation hospitalizations follow an exponential increase and have surpassed heart failure admissions," Trinquart says. (medindia.net)
  • Medicare records were used to obtain the incidence of new cardiovascular conditions during the five-year study including heart attack, atrial fibrillation, heart failure, ischaemic heart disease, hypertension, and stroke/transient ischaemic attack. (nepalnews.com)
  • But people with heart conditions already have a higher heart rate, which in many cases triggers arrhythmias, including atrial fibrillation. (earth.com)
  • For patients with atrial fibrillation , heart rate might be more important to watch, but many other heart diseases depend more on blood pressure. (clevelandclinic.org)
  • The S1 heart sound is intensified due to the increased cardiac output. (wikipedia.org)
  • Both sympathetic and parasympathetic stimuli flow through the paired cardiac plexus near the base of the heart. (wikipedia.org)
  • A substantial and relatively old body of heart rhythm literature ties HRV alterations to posttraumatic stress disorder , physician occupational stress, sleep disorders, depression , autonomic nervous system derangements, various cardiac arrhythmias, fatigue, overexertion, medications, and age itself. (medscape.com)
  • The Central Minnesota Heart Center at St. Cloud Hospital also known as MN Heart is a comprehensive cardiac care center dedicated to the discovery, management and control of cardiac disease in the adult population. (mnheart.com)
  • Studies show that people who have faster baseline heart rates are more likely to have cardiac problems and premature cardiac death," Dr. Laffin says. (clevelandclinic.org)
  • But our cardiac arrest survival rate remains a black mark on that otherwise impressive quality of life report card. (amnews.com)
  • The increase in cardiac output during gestation is the result of an increase in heart rate and stroke volume. (medscape.com)
  • In late pregnancy, the cardiac output is increased due to the tachycardia rate. (medscape.com)
  • We can't fight heart disease and stroke without you! (heart.org)
  • High blood pressure with rapid heart rate can be seen with panic attack , anxiety , PTSD , stress reaction, hypertension , stroke , cocaine or methamphetamine intoxication, or benzodiazapine or ethyl alcohol (EtOH) withdrawal. (medicinenet.com)
  • People who have the condition have irregular heartbeat and could suffer from stroke, blood clots and heart failure. (engadget.com)
  • If your doctor notices an irregular rhythm during the 5- to 10-minute cool-down period after a stress test, she may take more proactive actions to control the factors that can trigger heart attack or stroke in the patient, such as high blood pressure, high cholesterol, high blood sugar, obesity and smoking. (livestrong.com)
  • This figure is comprised by 25,142 cases of ischaemic heart disease (IHD) and 18,654 cases of stroke. (worldatlas.com)
  • As opposed to a high heart rate, which can affect heart muscle function, a low heart rate is believed to put less stress on heart blood vessels and may inhibit cholesterol build-up, lowering the risk for heart attack and stroke. (qualityhealth.com)
  • Higher levels of greenness were associated with lower rates of heart conditions and stroke over time, both when an area maintained high greenness and when greenness increased," said study author Dr William Aitken of the University of Miami, US. (nepalnews.com)
  • But Dr. Laffin says there is enough clinical evidence to suggest that when blood pressure is even a little over your typical average over time, the risk for heart disease and stroke go up. (clevelandclinic.org)
  • Essentially, for each increment of 20 mmHg over 115 mmHg systolic, your risk of heart attack, stroke, heart failure or chronic kidney disease doubles," Dr. Laffin says. (clevelandclinic.org)
  • There are increased risk for: Atherosclerosis, Peripheral vascular disease, Coronary heart disease, Heart attack, Stroke and Type 2 diabetes. (bvsalud.org)
  • Therefore, stimulation of the accelerans nerve increases heart rate, while stimulation of the vagus nerve decreases it. (wikipedia.org)
  • The pulse rate is exactly equal to the heartbeat, as the contractions of the heart cause the increases in blood pressure in the arteries that lead to a noticeable pulse. (medicalnewstoday.com)
  • While the heart rate increases as a result of physical activity, an overall decrease in target heart rate is possible over time. (medicalnewstoday.com)
  • When the heart pumps, it increases the pressure locally and causes a pressure wave to travel through the circulatory system. (biopac.com)
  • To maintain sufficient blood flow to the organs, the heart rate increases. (qualityhealth.com)
  • The adrenaline, fight-or-flight takes over, and the heart rate increases as he's going through that critical phase of flight," observes Dr. Cheryl Lowry, an associate professor at the University of Texas Medical Branch in Galveston. (popsci.com)
  • Then his heart rate rapidly decreases after he's got the 'go to stay'-we can see a rapid drop-off, where his comfort level increases and he's back down to normal in no time. (popsci.com)
  • Hi I notice that my heartrate increases in meditation and does not decrease what could be the problem? (ananda.org)
  • As your workload increases, your heart rate will increase, as well. (archbold.org)
  • For example, if you are dehydrated, bleeding or have a severe infection, blood pressure typically decreases and heart rate increases. (clevelandclinic.org)
  • Help keep cardiovascular health top of mind - and heart. (heart.org)
  • Nervous influence over the heart rate is centralized within the two paired cardiovascular centres of the medulla oblongata. (wikipedia.org)
  • Body Comp offers a total body assessment with weight precise up to 50g, plus full body composition metrics (body fat and water percentage, plus muscle and bone mass), cardiovascular assessment (Standing Heart Rate, Vascular Age), and an Electrodermal Activity Score, providing the most complete and accurate overview of body metrics ever offered. (bestbuy.com)
  • Much as the sed rate and CRP are sensitivity indicators of infectious or inflammatory diseases, might the HRV score be a sensitivity indicator for nervous system (central and autonomic) and cardiovascular (especially heart rhythm) malfunctions? (medscape.com)
  • Cardiovascular training aims to reduce the target heart rate. (medicalnewstoday.com)
  • According to the Journal of Exercise Physiology, a slow return to a normal heart rate could mean the person has a great risk of developing diabetes, abdominal obesity, high cholesterol and other cardiovascular risks. (livestrong.com)
  • A total of 160,000 people die in the UK each year from heart and circulatory diseases, with 42,000 patients dying prematurely due to cardiovascular diseases (CVD). (worldatlas.com)
  • Also, the current trends for increased rates of high blood pressure, high cholesterol, and Type 2 diabetes cases in the Chinese population is expected to raise the number of CVD deaths by approximately 7.7 million, and cardiovascular events of all kinds by 21.3 million. (worldatlas.com)
  • The Czech Republic has a high mortality rate of 1,077 individuals per 100,000 of the population dying as a result of cardiovascular diseases and strokes. (worldatlas.com)
  • Typically, a lower resting heart rate is the result of efficient heart function and cardiovascular fitness. (archbold.org)
  • The analyses were adjusted for other factors that could be related to new-onset heart disease: age, sex, race/ethnicity, number of baseline cardiovascular conditions, and neighbourhood characteristics including median household income and walkability. (nepalnews.com)
  • What is a resting heart rate? (heart.org)
  • Is resting heart rate different by age? (heart.org)
  • When it comes to resting heart rate, lower is better. (heart.org)
  • Studies have found that a higher resting heart rate is linked with lower physical fitness and higher blood pressure and body weight. (heart.org)
  • Bradycardia is defined as a resting heart rate below 60 bpm. (wikipedia.org)
  • Tachycardia is defined as a resting heart rate above 100 bpm, though persistent rest rates between 80 and 100 bpm, mainly if they are present during sleep, may be signs of hyperthyroidism or anemia (see below). (wikipedia.org)
  • I have been enamored of watching my step count, active zone minutes, resting heart rate, active heart rate, various sleep scores, and breathing rate (and, of course, a manually entered early morning daily body weight) for several years. (medscape.com)
  • I even check my "readiness score" (a calculation using resting heart rate, recent sleep, recent active zone minutes, and perhaps HRV) each morning and adjust my behaviors accordingly. (medscape.com)
  • Highly trained athletes may have a resting heart rate below 60 bpm , sometimes reaching 40 bpm. (medicalnewstoday.com)
  • The resting heart rate can vary within this normal range. (medicalnewstoday.com)
  • In healthy individuals, an effective program and healthy diet can also lower significantly resting heart rate. (livestrong.com)
  • For those not familiar with it, it is the difference between your maximum heart rate and your resting heart rate. (bikeforums.net)
  • ASSIC Resting heart rate(HR) allows for the measure of baseline heart rate required for the body to maintain efficient blood delivery to the organs in a steady resting state to maintain well being (homeostasis). (apple.com)
  • The researchers concluded that a higher resting heart rate is a risk factor for a shorter life expectancy. (qualityhealth.com)
  • High resting heart rate may shorten life: study. (qualityhealth.com)
  • Physically active adults (and athletes) often have a resting heart rate slower than 60 BPM. (goredforwomen.org)
  • Most heart rate monitors display your resting heart rate and allow you to train using heart rate zones. (archbold.org)
  • First things first - if you're considering an exercise plan that involves heart rate training, you must first calculate your average resting heart rate. (archbold.org)
  • Most smartwatches and wearable fitness dives will keep track of your resting heart rate for you. (archbold.org)
  • There are five heart rate zones and each one is based on the intensity of training with regard to your resting heart rate, a minimum heart rate, and maximum heart rate. (archbold.org)
  • For example, a fit person may have a resting heart rate in their 50s or, in some cases, even their 40s. (clevelandclinic.org)
  • The most common cause of a high resting heart rate is being deconditioned (in other words, out of shape). (clevelandclinic.org)
  • To measure your resting heart rate and blood pressure, pick a reliable and reproducible time, Dr. Laffin advises. (clevelandclinic.org)
  • The Heart Study app monitored the participants' heart rhythm to look for the presence of an irregular pulse. (engadget.com)
  • In some people, the heart rate remains elevated after exercise, and electrical pulses from the heart are irregular. (livestrong.com)
  • Some stimulants found in cough and cold medications and in herbal or nutritional supplements can cause irregular heart rhythms. (qualityhealth.com)
  • Participants are excluded from this component based on medical conditions, medications, physical limitations, limits on heart rate and blood pressure, and irregular heart rates. (cdc.gov)
  • It is important to identify whether a person's heart rate sits within the normal range. (medicalnewstoday.com)
  • A person's heart rate should fall within this range when exercising at 50-85% intensity, also known as exertion. (medicalnewstoday.com)
  • The test can reveal conditions--such as clogged arteries--that don't show up when the person's heart rate is normal. (livestrong.com)
  • As a source of valuable information about a person's affective state, heart rate data has the potential to improve both understanding and experience of human-computer interaction. (researchgate.net)
  • Bradycardia is a low heart rate, defined as below 60 bpm at rest. (wikipedia.org)
  • Your heart rate may fall below 60 BPM during deep sleep. (goredforwomen.org)
  • This section discusses target heart rates for healthy persons, which would be inappropriately high for most persons with coronary artery disease. (wikipedia.org)
  • The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve. (wikipedia.org)
  • During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. (wikipedia.org)
  • The Centers for Disease Control and Prevention (CDC) state that the maximum heart rate during exercise should be roughly equal to 220 bpm minus the age of the person. (medicalnewstoday.com)
  • In the United Kingdom (UK), coronary heart diseases (CHD) are responsible for a high number of the deaths in the country each year. (worldatlas.com)
  • Almost half of these CVD related deaths are due to coronary heart diseases. (worldatlas.com)
  • According to WHO data from 2014, coronary heart diseases was responsible for 34.04% of total deaths in the country. (worldatlas.com)
  • Similar to the current situation, ischaemic heart diseases and cerebrovascular diseases will continue to be the leading causes of deaths in this country. (worldatlas.com)
  • Not only do they keep us more active, they can also detect a variety of heart diseases without needing any additional bands or accessories. (macworld.com)
  • For the cost of one emergency room visit for a heart attack, trees could be planted in a neighbourhood with 100 residents and potentially prevent ten heart diseases in this group," Dr Aitken concluded. (nepalnews.com)
  • Carbon - disulfide (75150) has been associated with heart and artery diseases. (cdc.gov)
  • When a human sleeps, a heartbeat with rates around 40-50 bpm is common and is considered normal. (wikipedia.org)
  • Emily's racing heartbeat Heart sounds of a 16 year old girl immediately after running, with a heart rate of 186 BPM. (wikipedia.org)
  • Analyze your heartbeat with the heart rate monitor app, and perform stress test using the heartbeat checker. (google.com)
  • Due to this, the heart can pump a great volume of blood with each heartbeat, meaning it can beat less to get the necessary nutrients and oxygen to different parts of the body, making it more efficient. (medicalnewstoday.com)
  • Heart Rate is a free health application that tracks your pulse and generates personal heartbeat stats. (producthunt.com)
  • Why Heart Attacks Surge Among School-Aged Children? (medindia.net)
  • Dietary choices and a sedentary lifestyle are major factors in the rise of heart attacks among school-aged children. (medindia.net)
  • The trials were undertaken to determine whether the use of medications could reduce the number of heart attacks, strokes, and heart failure in people over 55 with established but stable heart disease. (qualityhealth.com)
  • As people age, this micro-chaos tends to diminish, and there is evidence linking this condition to sudden death for people who have had previous heart attacks. (news-medical.net)
  • It's even more concerning given Danville's large and growing population of retirees, who may be more prone to suffering heart attacks. (amnews.com)
  • Don't take your readings right after exercising - unless you're trying to establish a baseline for what's called active blood pressure and heart rate. (clevelandclinic.org)
  • Now that you have a target, you can monitor your heart rate to make sure you're in the zone. (heart.org)
  • They are often used by athletes to track their heart rates during exercise and by those who want to monitor their heart health. (bestbuy.com)
  • Get more insights about your heart health with a smart ecg heart rate monitor app: check heart rate, pulse and blood pressure, measure health, stress and productivity. (google.com)
  • Heart rate monitor may cause hot LED flash. (google.com)
  • No matter what kind of workout you're doing, the best heart rate monitor can provide essential information about how much physical energy you're exerting. (active.com)
  • To help you determine which heart rate monitor is right for you, the ACTIVE Reviews Team has put in the research to find the most accurate, high-quality trackers. (active.com)
  • Simply put, this is the most precise and exacting heart rate monitor you'll find. (active.com)
  • If your primary goal is to have the most accurate information possible, this is the heart rate monitor you need. (active.com)
  • Bluetooth connectivity allows you to sync the heart rate monitor with a range of fitness apps and training devices. (active.com)
  • Monitor your heart rate with maximum precision and connect your heart rate to a great variety of training devices with Bluetooth and ANT+. (probikekit.com)
  • Suitable for swimming - The 5 kHz transmission makes sure you can monitor your heart rate even in water. (probikekit.com)
  • At the heart of its success is FR70's wireless ANT+® technology, which allows it to connect to other ANT+ compatible devices, like the included heart rate monitor or optional foot pod. (woot.com)
  • FR70 also connects wirelessly to a heart rate monitor, providing instant feedback about how hard you're working. (woot.com)
  • Both Suunto and Polar are always neck-and-neck when it comes to heart rate monitor technology. (feedthehabit.com)
  • Heart-rate feedback is an excellent way to monitor workout intensity and can help you develop a training plan that will improve fitness and overall heart health. (archbold.org)
  • However, if you don't have a heart rate monitor and want to calculate your heart rate on your own, it's easy to do. (archbold.org)
  • Being mindful of your heart zones is a good way to monitor how hard you are training. (archbold.org)
  • If you currently own a wearable device or are interested in buying one, check out the links below to learn how you can monitor your heart rate zones with some of the most popular fitness trackers on the market today. (archbold.org)
  • The first fastest & most accurate mobile heart rate monitor. (producthunt.com)
  • Track your workouts with your Apple Watch or Bluetooth heart rate monitor from Polar, Wahoo or Scosche to see your progress over time. (producthunt.com)
  • The heart rate monitor training zones according to Zoladz are explained in this section. (best-running-tips.com)
  • Read this section carefully so you know how to use your heart rate monitor in running training. (best-running-tips.com)
  • His heart rate monitor training methods work based only on your max heart rate for running. (best-running-tips.com)
  • As you see, the calculations for the Zoladz heart rate monitor training zones are not that difficult. (best-running-tips.com)
  • A method much more used in heart rate monitor training is the method of Karvonen. (best-running-tips.com)
  • The Karvonen Heart Rate Monitor Training Method uses both your maximum heart rate and your rest heart rate . (best-running-tips.com)
  • And before I forget, check out the Heart Rate Monitor Training page for a lot more information about how to properly train with a heart rate monitor. (best-running-tips.com)
  • Heart rate was monitored continuously using an automated monitor with four electrodes connected to thorax and abdomen of the participant and was recorded at the end of warm-up, each exercise stage, and each minute of recovery. (cdc.gov)
  • The study included 30 Atlanta-area residents with lung disease (chronic obstructive pulmonary disease) or heart disease (previous myocardial infarction). (medindia.net)
  • Other names for heart attack include acute myocardial infarction, coronary thrombosis, and coronary occlusion. (medindia.net)
  • They identified smoking, alcohol consumption, body mass index, blood pressure, diabetes, and history of myocardial infarction or heart failure at an index age as risk factors. (medindia.net)
  • Being diagnosed with AF in 2016 and then further finding a missed congenital defect which needed open heart surgery I downloaded this app prior to surgery in 2016. (instantheartrate.com)
  • Find out what normal resting and maximum heart rates are for your age and how exercise intensity and other factors affect heart rate. (heart.org)
  • Target heart rate during moderate intensity activities is about 50-70% of maximum heart rate, while during vigorous physical activity it's about 70-85% of maximum. (heart.org)
  • If your heart rate is too low, and the intensity feels "light" to "moderate," you may want to push yourself to exercise a little harder, especially if you're trying to lose weight. (heart.org)
  • This demonstrates the full capability of the heart, and it is normally reached through high-intensity exercise. (medicalnewstoday.com)
  • One way of checking physical activity intensity is to determine whether your pulse or heart rate is within the target zone during physical activity. (cdc.gov)
  • For moderate-intensity physical activity , your target heart rate should be between 64% and 76% 1 , 2 of your maximum heart rate. (cdc.gov)
  • This shows that moderate-intensity physical activity for a 50-year-old person will require that the heart rate remains between 109 and 129 bpm during physical activity. (cdc.gov)
  • For vigorous-intensity physical activity , your target heart rate should be between 77% and 93% 1 , 2 of your maximum heart rate. (cdc.gov)
  • The study, which was conducted by Cardiogram and the University of California at San Francisco, used 14,011 subjects and some 200 million heart rate sensor measurements to train DeepHeart and test the accuracy of the neural network's ability to distinguish between people with and without diabetes. (macworld.com)
  • A heart beat may be detected through a variety of measurements. (biopac.com)
  • Change in heart rate with change in body temperature was assessed by extracting pairs of simultaneous body temperature and corresponding heart rate measurements from the electronic medical record: 472,941 simultaneous pairs were obtained from the 9,046 patients admitted during the study period. (lu.se)
  • The screening is done prior to the treadmill test using questions in the household interview, questions administered by the physician in the NHANES Mobile Examination Center (MEC) and aspects of the physician examination such as measurements of heart rate and blood pressure. (cdc.gov)
  • Top fitness apps, gym equipment, sports and smart watches and other training devices: there are tonnes of options to choose from when you want to see your heart rate and record your workouts. (probikekit.com)
  • For example, for a 50-year-old person, a maximum heart rate calculation would be 220 - 50 years = 170 bpm. (medicalnewstoday.com)
  • "Find Rate" - available as a calculation channel during data acquisition and via the "Analysis" menu (or "Transform" menu in older software versions) after data have been acquired. (biopac.com)
  • The algorithm used to derive rates via "Find Rate" or "Rate" calculation channels is extensively documented in Application Note 142 . (biopac.com)
  • This table shows target heart rate zones for different ages. (heart.org)
  • Learn how this fat-burning range breaks down into three specific heart-rate zones, the benefits of each and how to calculate them. (betternutrition.com)
  • The table below from the American Heart Association shows target heart rate zones for different ages. (archbold.org)
  • Many heart rate monitors come pre-programmed with built-in zones. (archbold.org)
  • Additionally, they have the capability for you to adjust your heart rate zones to meet your specific needs. (archbold.org)
  • Therefore you use heart rate zones . (best-running-tips.com)
  • I have, however, added a Zoladz Heart Rate Training Zones Calculator to this page for your convenience. (best-running-tips.com)
  • How do I find my pulse or heart rate? (heart.org)
  • The researchers investigated the impact alcohol concentration had on different electrocardiogram parameters besides heart rate. (earth.com)
  • As you exercise, periodically check your heart rate. (heart.org)
  • In time, you'll be able to exercise comfortably at up to 85 percent of your maximum heart rate. (heart.org)
  • This is because exercise strengthens the heart muscle. (medicalnewstoday.com)
  • As the body of each individual will react to exercise differently, the target heart rate is presented as a range known as the target heart rate zone. (medicalnewstoday.com)
  • It is recommended that people exercise regularly to work towards a healthy target heart rate. (medicalnewstoday.com)
  • A stress test should include measuring how quickly your elevated heart rate returns to normal after exercise. (livestrong.com)
  • Your pulse two minutes after exercise is what is called your 'recovery heart rate,' and that rate will go down as you become more fit. (livestrong.com)
  • The heart rate of a typical individual will return to resting levels shortly after light or moderate exercise.The heart rates of athletes--particularly endurance-trained and strength-trained athletes--will return to normal after exercise faster than nonathletes. (livestrong.com)
  • Doctors use stress tests to examine how well a heart functions during exercise. (livestrong.com)
  • A stress test uses a blood pressure cuff and an electrocardiograph to measure how exercise on a treadmill or exercise bike affects your blood pressure, heart rate and the heart's electrical activity. (livestrong.com)
  • While uncommon rhythms during exercise don't seem to be cause for concern, abnormal pulses in the heart ventricles that occur only after exercise can indicate a higher risk of imminent death, the Family Health Guide says. (livestrong.com)
  • People who show signs of future heart problems may still be advised by their doctor to exercise. (livestrong.com)
  • But most doctors will want to confer with their patients before a patient with potential heart problems begins or continues an exercise program. (livestrong.com)
  • HRR is more related to VO2 max whereas the ability to exercise at higher and higher percentages of HRR (added to the resting rate) equates more to metabolic health or at least how I think of it. (bikeforums.net)
  • The importance of balanced diet life style and exercise for controlling heart disease. (medindia.net)
  • In people who exercise regularly or take medications that slow the heart, the rate may drop to the 50s. (qualityhealth.com)
  • The maker of wearable activity trackers was hit with a class action lawsuit Tuesday claiming the device used to measure heart rates in the company's Charge HR and Surge fitness watches "do not and cannot consistently and accurately record wearers' heart rates" during exercise. (kqed.org)
  • The lawsuit claims testing has confirmed that the San Francisco-based company's PurePulse Trackers "consistently mis-record heart rates by a very significant margin, particularly during exercise. (kqed.org)
  • According to the suit, one of the plaintiffs, Kate McLellan, of Murietta, California, compared her real-time heart rate readings from a Charge HR with those on a stationary exercise machine and noticed a discrepancy. (kqed.org)
  • Heart rate training is training or exercise that involves keeping your heart rate within a certain range for a designated period of time. (archbold.org)
  • Measuring your heart rate during exercise gives you an indicator of how hard you are working. (archbold.org)
  • The American Heart Association (AHA) advises that people aim to have a heart rate between 50% and 8% of their maximum heart rate during exercise. (archbold.org)
  • Knowing your target heart rate and paying attention to your heart rate zone will help you hit the "sweet spot" during your exercise routine. (archbold.org)
  • How Do You Measure A Target Exercise Heart Rate? (mnheart.com)
  • At the end of warm-up and each exercise stage, participants were asked to rate their perceived exertion using the Borg scale. (cdc.gov)
  • The Stanford researchers that conducted Apple's Heart Study have published their paper in the New England Journal of Medicine . (engadget.com)
  • A study by Canadian researchers has found a direct link between heart rate at rest and the risk of death in people with stable heart disease. (qualityhealth.com)
  • The researchers asked them to simply stare at one another for three minutes straight in as calm a manner as possible (ahem) while they monitored the couple's heart rates. (nature.com)
  • It is no surprise then that when the researchers compared the measure of heart rates between people not involved in a romantic relationship, the blue and red lines did not match. (nature.com)
  • The researchers also found that it was the women who tended to adjust their heart rates to their partners. (nature.com)
  • The researchers also examined whether planting more vegetation in a locality would be accompanied by reductions in heart disease over time. (nepalnews.com)
  • The researchers first compared heart health among those continually living in high versus low greenness areas during the five-year study. (nepalnews.com)
  • The researchers then compared heart health in participants whose neighbourhood became greener versus those who continued to live in areas with low vegetation. (nepalnews.com)
  • The new study was conducted by researchers from the LMU University Hospital Munich Department of Cardiology in order to assess the acute effects of alcohol on heart health. (earth.com)
  • During the 2015 Munich Oktoberfest, researchers recorded the heart rate activity of over 3,000 participants using electrocardiograms (ECG) and measured breath alcohol concentrations. (earth.com)
  • The researchers also compiled data on the participants' age and sex, if there was a history of heart disease, and if they smoked. (earth.com)
  • It also measures your heart rate . (bestbuy.com)
  • It measures your heart rate and then calculates your performance based on your fitness level with suggested workout schedules and duration. (feedthehabit.com)
  • Your Apple Watch measures your heart rate every 4 minutes during the day. (producthunt.com)
  • And the heart rate data is accurate and precise, so you can count on these reliable metrics to inform your training and recovery. (active.com)
  • If we can start extrapolating the heart-rate data from Apple Watch to detect ailments that aren't specific to the heart, there's no telling how much of a life-saver it could be. (macworld.com)
  • Heart rate can be derived from various data sources but is not a physically measurable quantity, thus it is " computed" rather than measured. (biopac.com)
  • With the BPM measurement saved as a channel in the graph, the heart rate is available for further computations (e.g., mean heart rate over long segments of data). (biopac.com)
  • If you highlight a segment of data containing multiple heartbeats, the BPM measurement provides a meaningless answer, NOT the average heart rate over the selected segment. (biopac.com)
  • Aimed at providing heart rate data for mobile apps like BioLogic's own BikeBrain , Strava, and countless others the heart rate strap will function with Bluetooth enabled cycling computers, like the Wahoo's RFLKT , as well. (bikerumor.com)
  • Built-in memory with Polar Beat - Polar H10 has a built-in memory for heart rate data from one training session. (probikekit.com)
  • In the gym or on the road, FR70 tracks all your workout data, including time, heart rate, calories burned and more. (woot.com)
  • Instant Heart Rate was used to gather HR-PPG data for the e-heart health study at UCSF. (instantheartrate.com)
  • There are few data available on the relationship between body temperature and heart rate in critically ill patients. (lu.se)
  • 2" - Pregnant more than 12 weeks: pregnant women are excluded from the component because physiologic changes with pregnancy affect heart rate, and therefore the interpretation of the data. (cdc.gov)
  • The research was focused on the collection of physiological data, namely heart rate and the evaluation of these data in the context of identification of arousal during individual teaching activities of the teaching process. (bvsalud.org)
  • The mortality rate for heart disease decreased at a faster pace than the cancer death rate during that period. (cdc.gov)
  • Because of its functionality, heart rate monitors can serve as guardrails for pretty much any type of workout, from HIIT to rowing to running on the treadmill . (active.com)
  • Stay motivated and accomplish your fitness goals with FR70, a sleek fitness watch plus workout tool that tracks your time, heart rate and calories burned. (woot.com)
  • There are heart rate monitors and then there are workout performance and coaching systems. (feedthehabit.com)
  • To maximize performance and get the most benefit from your workout, you need to find and stay within your target heart rate zone throughout your workout. (archbold.org)
  • This easy-to-use app empowers you to stay tuned to your heart activity and tweak your cardio workout. (producthunt.com)
  • Even if you're not a gym rat or elite athlete, knowing your heart rate (or pulse) can help you track your health and fitness level. (heart.org)
  • I love that it keeps track of all my metrics, such as weight, body composition, nerve health, vascular age, and heart rate . (bestbuy.com)
  • One app for hrv monitoring - many heart health insights. (google.com)
  • Welltory is here for you and your heart health. (google.com)
  • While a normal heart rate does not guarantee that a person is free of health problems, it is a useful benchmark for identifying a range of health issues. (medicalnewstoday.com)
  • CVS Health is a proud national sponsor of the American Heart Association's Go Red for Women movement. (goredforwomen.org)
  • All health/medical information on this website has been reviewed and approved by the American Heart Association, based on scientific research and American Heart Association guidelines. (goredforwomen.org)
  • Check your heart rate from home & gain valuable insight into your heart health. (instantheartrate.com)
  • Explore our library of heart health articles on how you can live a healthier and happier life. (instantheartrate.com)
  • Stay on top of your health with printable heart reports to share with your doctor. (instantheartrate.com)
  • Working cooperatively, five major metro Detroit health systems improved heart attack survival rates with their Detroit Cardiogenic Shock Initiative, they announced Wednesday. (crainsdetroit.com)
  • But each measures distinctly different factors related to your heart health. (clevelandclinic.org)
  • The Polar H10 Heart Rate Sensor is trusted by the pros, and it's not hard to understand why. (active.com)
  • While Apple and Google have been rumored to be working on hardware capable of monitoring glucose levels , Cardiogram's study used nothing more than machine learning and the Apple Watch's heart rate sensor to detect whether a user has diabetes. (macworld.com)
  • The heart rate sensor that you wear already from the Apple Watch may actually be able to detect signs of diabetes," Cardiogram co-founder Brandon Ballinger told Macworld. (macworld.com)
  • Cardiogram has used the Apple Watch's heart rate sensor to detect diabetes in a new study. (macworld.com)
  • When it comes to accuracy and connectivity, Polar H10 heart rate sensor is the go-to choice. (probikekit.com)
  • The most accurate heart rate sensor in Polar's history, Polar H10 is polished to the max in all aspects. (probikekit.com)
  • Precision - Widely recognised for its top precision by many sources, Polar H10 is the most accurate heart rate sensor in Polar's history. (probikekit.com)
  • PurePulse provides better overall heart rate tracking than cardio machines at the gym, as it tracks your heart rate continuously - even while you're not at the gym or working out," the statement said. (kqed.org)
  • Heart rate was monitored continuously and hourly values were recorded in the electronic medical record. (lu.se)
  • Log blood pressure and heart rate to make sure that you are in good shape! (google.com)
  • Each puff of nicotine from tobacco smoke raises heart rate and blood pressure. (qualityhealth.com)
  • Blood pressure and heart rate go hand in hand in most people's minds. (clevelandclinic.org)
  • It is true that blood pressure and heart rate often rise and fall together, Dr. Laffin says. (clevelandclinic.org)
  • However, if your heart rate rises, that doesn't automatically mean your blood pressure will rise - or vice versa. (clevelandclinic.org)
  • Keep in mind that heart rate and blood pressure are a customized fit. (clevelandclinic.org)
  • Low blood pressure can be a bit trickier, especially in older patients and those with heart disease. (clevelandclinic.org)
  • Blood pressure and heart rate changes in children when they read aloud in school. (cdc.gov)
  • The pulse is often confused with the heart rate but refers instead to how many times per minute the arteries expand and contract in response to the pumping action of the heart. (medicalnewstoday.com)
  • Your maximum heart rate is about 220 minus your age. (heart.org)
  • Some drugs and medications affect heart rate, meaning you may have a lower maximum heart rate and target zone. (heart.org)
  • It is also worth noting the maximum heart rate. (medicalnewstoday.com)
  • You can estimate your maximum heart rate based on your age. (cdc.gov)
  • For example, a 20-year-old's maximum heart rate would be around 200 bpm (220 minus 20 + 200 bpm). (archbold.org)
  • Just put in your maximum heart rate and then press the "click me"-button. (best-running-tips.com)
  • After all you only need your maximum heart rate. (best-running-tips.com)
  • Running Max Heart Rate - For the Zoladz method to work properly you need to establish your maximum heart rate. (best-running-tips.com)
  • The rate can be affected by factors like stress, anxiety, hormones, medication, and how physically active you are. (heart.org)
  • Each participant will undergo a physical examination to rule out certain risk factors such as diabetes, systemic hypertension, and respiratory and heart abnormalities. (news-medical.net)
  • These observations will help to correctly interpret heart rate values at different body temperatures and enable more accurate evaluation of other factors associated with tachycardia. (lu.se)
  • Risk factors may include being born into a family where heart problems exist, as well as certain environmental or dietary exposures which can be controlled by the individual. (cdc.gov)
  • If disease or injury weakens the heart, the organs will not receive enough blood to function normally. (medicalnewstoday.com)
  • Cardiogenic shock, a complication as a result of a heart attack, occurs when the heart cannot pump enough blood to vital organs. (crainsdetroit.com)
  • Sodium azide is more harmful to the heart and the brain than to other organs, because the heart and the brain use a lot of oxygen. (cdc.gov)
  • Abnormalities of heart rate sometimes indicate disease. (wikipedia.org)
  • Heart Disease Hospitalization Rates for 2018 through 2020 for Blacks Aged 65 Years and Older by County. (cdc.gov)
  • The heart rate gets progressively slower as a person moves through childhood toward adolescence. (medicalnewstoday.com)
  • As water and blood are incompressible fluids, one of the physiological ways to deliver more blood to an organ is to increase heart rate. (wikipedia.org)
  • That added physiological stressor could have caused their hearts to beat faster. (popsci.com)
  • While heart rhythm is regulated entirely by the sinoatrial node under normal conditions, heart rate is regulated by sympathetic and parasympathetic input to the sinoatrial node. (wikipedia.org)
  • The accelerans nerve provides sympathetic input to the heart by releasing norepinephrine onto the cells of the sinoatrial node (SA node), and the vagus nerve provides parasympathetic input to the heart by releasing acetylcholine onto sinoatrial node cells. (wikipedia.org)
  • Parasympathetic influence on heart rate often acts to dampen sympathetic influence via innervation of the vagus nerve, which acts as a brake on the activity of the heart's natural pacemaker, the sympathetically driven sinoatrial node. (frontiersin.org)
  • In many cases, a pacemaker can regulate the heart's rhythm, speeding up the heart rate as needed. (goredforwomen.org)
  • The American Heart Association recommends hrv tracker for ambulatory cardiogram or electrocardiography interpretation. (google.com)
  • I typically settled on Heart Rate, Distance and Elapsed Time, but you can change that to your liking with the press of a button or two. (feedthehabit.com)
  • Relative to the time of a heart beat as indicated by an ECG spike, the timing of capillary ingress or of a pressure wave and concomitant increase in blood velocity depend on where in the body the pressure or flow measurement is made. (biopac.com)
  • Used in conjunction with the measurement boxes, Find Cycle provides some flexibility that Find Rate does not. (biopac.com)
  • To obtain an average heart rate, use a "Mean" measurement on a channel containing a computed rate. (biopac.com)
  • We find that a higher frame rate yields better results than a larger size of the moving measurement window. (researchgate.net)
  • I use this app to confirm the heart rate and try the vagal maneuver to reset the heart. (instantheartrate.com)
  • A very long time ago, when I ran clinical labs, one of the most ordered tests was the "sed rate" (aka ESR, the erythrocyte sedimentation rate). (medscape.com)
  • A healthy heart supplies the body with just the right amount of blood at the right rate for whatever the body is doing at that time. (medicalnewstoday.com)
  • The graph above does not actually show the heart rates of the man and woman changing with time. (nature.com)
  • Hook up Polar H10 with Polar Beat, Polar's free fitness and training app to get accurate real-time heart rate directly to your phone. (probikekit.com)
  • This also means that as you become more physically fit and your heart gets stronger, you will have to increase your workload to achieve the same fitness benefits over time. (archbold.org)
  • This is exciting because for the first time in two decades, we've found a way to save lives" of cardiogenic shock patients, said Theodore Schreiber, M.D., president of the DMC Heart Hospital. (crainsdetroit.com)
  • Written by American Heart Association editorial staff and reviewed by science and medicine advisors. (heart.org)
  • Featuring an ear clip that detects one's heart rhythm, the system notifies the user of the current number via voice inside the headphones, which avoids having to manually check the reading on a display. (medgadget.com)
  • However, heart rates from 50 to 60 bpm are common among healthy people and do not necessarily require special attention. (wikipedia.org)
  • The actual numbers vary because everyone's heart rate varies--even between similar people at similar fitness levels. (livestrong.com)
  • Heart Insight ® e-news is our trusted, award-winning monthly publication for people living with heart disease, their families and caregivers. (goredforwomen.org)
  • Heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the entire world. (instantheartrate.com)
  • 17.9 million people die each year from heart disease, that's an estimated 31% of all deaths worldwide. (instantheartrate.com)
  • Millions of people are using Instant Heart Rate to make sure they are living a heart healthy lifestyle. (instantheartrate.com)
  • According to new research, drinking alcohol makes your heart race and could cause arrhythmias in people with heart conditions. (earth.com)
  • There's a simple way to know: Your target heart rate helps you hit the bullseye so you can get max benefit from every step, swing and squat. (heart.org)
  • The ideal target heart rate reduces with age. (medicalnewstoday.com)
  • The following table shows the appropriate target heart rate zone for a range of ages. (medicalnewstoday.com)
  • Generally, to figure out whether you are exercising within the target heart rate zone, you must briefly stop exercising to take your pulse. (cdc.gov)
  • What is My Target Heart Rate? (archbold.org)
  • What if my heart rate is too high or too low? (heart.org)
  • If your heart rate is too high, you're straining. (heart.org)
  • Tachycardia is a high heart rate, defined as above 100 bpm at rest. (wikipedia.org)
  • It uses high-tech electrodes to make sure it's producing the most exact heart rate reading possible. (active.com)
  • The map shows that pockets of counties with high heart disease hospitalization rates - meaning the top quintile - are located in Texas, Louisiana, Florida, Ohio, Michigan, Illinois, and North Carolina. (cdc.gov)
  • Polar H10 comes with Polar Pro strap, a soft textile strap with high quality electrodes to make sure your heart rate is measured accurately and without interference. (probikekit.com)
  • The Heart Center is committed to providing excellent patient care, attracting high-caliber staff and developing state-of-the-art facilities. (mnheart.com)
  • This chart of Armstrong's heart rate is in the biomedical section of the Apollo 11 Mission Report. (popsci.com)
  • The American Heart Association states the normal resting adult human heart rate is 60-100 bpm. (wikipedia.org)
  • Normal heart sounds Normal heart sounds as heard with a stethoscope Problems playing this file? (wikipedia.org)
  • Normal resting heart rates range from 60 to 100 bpm. (wikipedia.org)
  • If the sed rate was normal, the patient probably did not have an infectious or inflammatory disease. (medscape.com)
  • In recent years, doctors have started examining what happens to a patient's heart as it returns to its normal pulse rate after a stress test. (livestrong.com)
  • In another study, those whose heart rates took longer than normal to recover were four times more likely to have died over the next three years, the Family Medical Guide reported. (livestrong.com)
  • Overall, throughout the entire mission, all three men's average heart rates were normal, according to the biomedical portion of the Apollo 11 report: Armstong's stayed highest at 71, Collins' was 60, and Aldrin's was 67. (popsci.com)
  • That means that even during launch, both Collins' and Aldrin's hearts were beating at the same rate yours might be as you just amble about your normal life. (popsci.com)
  • To reduce the amount of stress alcohol puts on the heart, the American Heart Association suggests limiting intake to two drinks a day for men and one a day for women. (qualityhealth.com)

No images available that match "heart rate"