Arrhythmias, CardiacCardiac ElectrophysiologyElectrophysiologyMyocytes, CardiacArrhythmia, SinusElectrocardiographyHeartDeath, Sudden, CardiacElectrophysiologic Techniques, CardiacHeart Conduction SystemTachycardia, VentricularAnti-Arrhythmia AgentsElectrophysiological PhenomenaCardiac Pacing, ArtificialCardiac OutputVentricular FibrillationAction PotentialsElectrophysiological ProcessesHeart VentriclesCardiac Surgical ProceduresHeart RateMyocardiumModels, CardiovascularHeart AtriaAtrial FibrillationVentricular Premature ComplexesCatheter AblationTachycardiaTachycardia, SupraventricularLong QT SyndromeDogsElectrocardiography, AmbulatoryTime FactorsPatch-Clamp TechniquesMyocardial ContractionHeart DiseasesDefibrillators, ImplantableVoltage-Sensitive Dye ImagingCardiomegalyNAV1.5 Voltage-Gated Sodium ChannelCardiac Complexes, PrematureCardiac CatheterizationAtrial FlutterAtrioventricular NodeBody Surface Potential MappingHeart FailureMembrane PotentialsMyocardial InfarctionHeart ArrestCardiomyopathiesSodium ChannelsElectric CountershockVentricular DysfunctionHeart BlockVentricular FunctionCalciumEchocardiographyPacemaker, ArtificialCardiac TamponadePericardiumEther-A-Go-Go Potassium ChannelsRats, Sprague-DawleyMyocardial IschemiaDisease Models, AnimalAtrial FunctionTorsades de PointesHemodynamicsPotassium Channels, Voltage-GatedTreatment OutcomeVentricular Function, LeftPotassium ChannelsAmiodaroneBlood PressureIon ChannelsFollow-Up StudiesPurkinje FibersRefractory Period, ElectrophysiologicalBradycardiaCardiac Imaging TechniquesSyncopeFlecainideCalcium SignalingProspective StudiesTelemetryMyocardial Reperfusion InjuryBundle of HisEpicardial MappingCardiomyopathy, DilatedAutonomic Nervous SystemIon Channel GatingHeart Defects, CongenitalMyoblasts, CardiacElectric StimulationEndocardiumNeuronsStroke VolumeRabbitsCardiac GlycosidesCardiac Output, LowCalcium Channels, L-Type