Cardiac ElectrophysiologyArrhythmias, CardiacElectrophysiological ProcessesElectrophysiologic Techniques, CardiacEpicardial MappingModels, CardiovascularHeartHeart Conduction SystemElectrophysiologyVoltage-Sensitive Dye ImagingMyocytes, CardiacElectrocardiographyElectrophysiological PhenomenaAction PotentialsAtrioventricular NodeHeart VentriclesLong QT SyndromeCatheter AblationComputer SimulationHeart RateArrhythmia, SinusMyocardiumPotassium ChannelsDeath, Sudden, CardiacTachycardia, VentricularAnti-Arrhythmia AgentsCardiac Pacing, ArtificialCardiac OutputVentricular FibrillationAlgorithmsCardiac Surgical ProceduresHeart AtriaAtrial FibrillationVentricular Premature ComplexesTachycardiaTachycardia, SupraventricularDogsElectrocardiography, AmbulatoryTime FactorsPatch-Clamp TechniquesMyocardial ContractionHeart DiseasesDefibrillators, ImplantableCardiomegalyNAV1.5 Voltage-Gated Sodium ChannelCardiac Complexes, PrematureCardiac CatheterizationAtrial FlutterBody Surface Potential MappingHeart FailureMembrane PotentialsMyocardial InfarctionHeart ArrestCardiomyopathiesSodium ChannelsElectric CountershockVentricular DysfunctionHeart BlockVentricular FunctionCalciumEchocardiographyPacemaker, ArtificialCardiac TamponadePericardiumEther-A-Go-Go Potassium ChannelsRats, Sprague-Dawley