Tachycardia, SupraventricularBradycardiaTachycardiaTachycardia, ParoxysmalTachycardia, VentricularTachycardia, Atrioventricular Nodal ReentryTachycardia, SinusElectrocardiographyTachycardia, Ectopic AtrialCatheter AblationAnti-Arrhythmia AgentsTachycardia, Ectopic JunctionalAtrioventricular NodeArrhythmias, CardiacWolff-Parkinson-White SyndromeHeart Conduction SystemCardiac Pacing, ArtificialAtrial Premature ComplexesHeart RateElectrophysiologic Techniques, CardiacBundle of HisHydrops FetalisFlecainideAtrial FlutterElectrocardiography, AmbulatoryTachycardia, Sinoatrial Nodal ReentryAmiodaroneDigoxinPostural Orthostatic Tachycardia SyndromeAtrial FibrillationCardiac Complexes, PrematurePre-Excitation SyndromesHeart BlockFetal DiseasesAccessory Atrioventricular BundleTachycardia, ReciprocatingHeart AtriaBody Surface Potential MappingSyncopeVentricular FibrillationSinoatrial NodeDefibrillators, ImplantableAtrioventricular BlockSotalolElectric CountershockVentricular Premature ComplexesPacemaker, ArtificialElectrocoagulationHypotensionTreatment OutcomeHeart Rate, FetalProcainamideFollow-Up StudiesArrhythmia, SinusHeart VentriclesBlood PressureVerapamilSick Sinus SyndromeElectrophysiologyVagus NerveApneaHeartPropafenoneRecurrenceBundle-Branch BlockTime FactorsDisopyramideDogsAdrenergic beta-AntagonistsRetrospective StudiesDeath, Sudden, CardiacHemodynamicsEchocardiographyAdenosineAntazolineInfant, NewbornHeart Defects, CongenitalCardiomyopathiesHydroxyzineAtrial FunctionProspective StudiesFinancial AuditReflexInjections, IntravenousAtropineCardiomyopathy, DilatedCryosurgeryTricuspid AtresiaCardiac CatheterizationFetal HeartPostoperative ComplicationsCardiac Surgical ProceduresEndocardiumFetal DistressHeterotaxy SyndromeBaroreflexIsoproterenolPropanolaminesLavandulaRefractory Period, Electrophysiological