Arrhythmias, CardiacSyncopeElectrocardiography, AmbulatoryDizzinessTachycardia, SupraventricularElectrocardiographyTachycardia, ParoxysmalHeart SoundsTachycardia, SinusAtrial Premature ComplexesTachycardiaVentricular Premature ComplexesTachycardia, Atrioventricular Nodal ReentryPheochromocytomaCatheter AblationWolff-Parkinson-White SyndromeParagangliomaDyspneaAtrioventricular NodeThyroiditis, SubacuteTachycardia, VentricularSick Sinus SyndromeMedical History TakingDiscriminant AnalysisAdrenal Gland NeoplasmsTilt-Table TestChest PainHeart NeoplasmsHeadacheAtrial FibrillationAnti-Arrhythmia AgentsDeath, Sudden, CardiacEchocardiographyHeart BlockCardiac Surgical ProceduresBundle-Branch BlockTreatment OutcomeDefibrillators, ImplantableHeart DiseasesHeart Conduction SystemFatigueAmbulatory CareHeart RateProspective StudiesFollow-Up StudiesCardiac Pacing, ArtificialHeart AtriaTime FactorsPredictive Value of TestsHeart VentriclesRecurrenceFamily PracticeRetrospective StudiesTomography, X-Ray ComputedSeverity of Illness IndexQuestionnairesHypertensionPrevalenceRisk Factors