Arrhythmias, CardiacArrhythmia, SinusMyocytes, CardiacElectrocardiographyHeartDeath, Sudden, CardiacCardiac OutputTachycardia, VentricularAnti-Arrhythmia AgentsVentricular FibrillationCardiac Surgical ProceduresHeart Conduction SystemCardiac Pacing, ArtificialHeart VentriclesHeart RateMyocardiumVentricular Premature ComplexesTachycardiaElectrocardiography, AmbulatoryHeart DiseasesTime FactorsCardiac Complexes, PrematureLong QT SyndromeMyocardial ContractionAtrial FibrillationCardiomegalyHeart ArrestDogsElectrophysiologic Techniques, CardiacCardiomyopathiesMyocardial InfarctionDefibrillators, ImplantableHeart FailureCardiac CatheterizationHeart AtriaCardiac TamponadeSleep DisordersMyocardial IschemiaEchocardiographyTachycardia, SupraventricularModels, CardiovascularVentricular DysfunctionTreatment OutcomeCatheter AblationNAV1.5 Voltage-Gated Sodium ChannelAtrial FlutterHemodynamicsAction PotentialsFollow-Up StudiesBradycardiaElectric CountershockCardiac ElectrophysiologyProspective StudiesHeart BlockVentricular Function, LeftDisease Models, AnimalBlood PressureCardiac Imaging TechniquesFlecainideRisk FactorsCardiomyopathy, DilatedHeart Defects, CongenitalMyocardial Reperfusion InjuryAmiodaronePacemaker, ArtificialTorsades de PointesMyoblasts, CardiacStroke VolumeCardiac GlycosidesCardiac Output, LowPericardiumDeath, SuddenVentricular RemodelingVentricular FunctionElectrophysiologyCardiac MyosinsCardiotonic AgentsDigitalis GlycosidesVentricular Dysfunction, LeftHeart TransplantationRetrospective StudiesCalciumAutonomic Nervous SystemPostoperative ComplicationsCardiac VolumeRats, Sprague-DawleyOut-of-Hospital Cardiac ArrestSodium ChannelsEther-A-Go-Go Potassium ChannelsSyncopeAdrenergic beta-AntagonistsPredictive Value of TestsHeart Function TestsTroponin IBody Surface Potential MappingTelemetryRats, WistarAtrioventricular BlockConnexin 43Fibrosis