Arrhythmias, CardiacHeartHeart RateArrhythmia, SinusHeart FailureElectrocardiographyTachycardia, VentricularAnti-Arrhythmia AgentsHeart DiseasesVentricular FibrillationHeart Defects, CongenitalHeart TransplantationVentricular Premature ComplexesHeart AtriaElectrocardiography, AmbulatoryTachycardiaMyocardiumHeart BlockHeart Conduction SystemDeath, Sudden, CardiacFetal HeartCardiac Complexes, PrematureAtrial FibrillationLong QT SyndromeMyocytes, CardiacMyocardial IschemiaCardiac Pacing, ArtificialHeart ValvesTachycardia, SupraventricularDefibrillators, ImplantableElectrophysiologic Techniques, CardiacDogsTime FactorsMyocardial ContractionCatheter AblationMyocardial InfarctionAtrial FlutterVentricular DysfunctionMyocardial Reperfusion InjuryHeart VentriclesModels, CardiovascularAction PotentialsCardiomyopathiesHeart Function TestsAmiodaroneHemodynamicsFlecainideElectric CountershockNAV1.5 Voltage-Gated Sodium ChannelFollow-Up StudiesTorsades de PointesCoronary DiseaseCardiomyopathy, DilatedEchocardiographyRisk FactorsAdrenergic beta-AntagonistsHeart Arrest, InducedVentricular Function, LeftDigitalis GlycosidesHeart ArrestTreatment OutcomeAutonomic Nervous SystemPerfusionDeath, SuddenCardiotonic AgentsStroke VolumeProspective StudiesDisease Models, AnimalTelemetryVentricular Dysfunction, LeftBradycardiaCardiomegalyPacemaker, ArtificialVoltage-Sensitive Dye ImagingHeart SeptumCardiac Output, LowAconitineAtrial Premature ComplexesEndocardiumPropafenoneEther-A-Go-Go Potassium ChannelsEncainideSyncopeBody Surface Potential MappingHeart InjuriesConnexin 43Tetralogy of FallotAtrioventricular NodeExercise TestCardiac ElectrophysiologyElectrophysiologyEpinephrineRetrospective StudiesSodium ChannelsVentricular RemodelingPredictive Value of TestsRats, WistarSympathetic Nervous SystemSinoatrial NodeIsoproterenol