Heart Conduction SystemElectrocardiographyAction PotentialsLong QT SyndromeVentricular FunctionArrhythmias, CardiacTorsades de PointesHeart VentriclesAnti-Arrhythmia AgentsPotassium Channels, Voltage-GatedPotassium ChannelsPericardiumEther-A-Go-Go Potassium ChannelsHeartDelayed Rectifier Potassium ChannelsDogsSotalolRefractory Period, ElectrophysiologicalPotassium Channel BlockersElectrophysiologyEndocardiumMembrane PotentialsVectorcardiographyVentricular FibrillationKCNQ1 Potassium ChannelCardiac Pacing, ArtificialBrugada SyndromePatch-Clamp TechniquesElectrophysiologic Techniques, Cardiac4-AminopyridinePurkinje FibersPotassiumTachycardia, VentricularModels, CardiovascularBody Surface Potential MappingMyocytes, CardiacHeart RateGuinea PigsDeath, Sudden, CardiacPhenethylaminesQuinidineSodium ChannelsMyocardiumHeart AtriaAtrial FunctionCardiac ElectrophysiologyCalciumCardiac Complexes, PrematureTime FactorsNAV1.5 Voltage-Gated Sodium ChannelKv1.5 Potassium ChannelElectric ConductivityTetraethylammoniumShal Potassium ChannelsIon Channel GatingKCNQ Potassium ChannelsRabbitsPapillary MusclesSodium Channel BlockersVoltage-Sensitive Dye ImagingMagnetocardiographyMyocardial ContractionCalcium Channels, L-TypeMexiletineSodiumChromansRomano-Ward SyndromeTetraethylammonium CompoundsAcetanilidesIon ChannelsBarium CompoundsElectric StimulationFlecainideMicroelectrodesShaw Potassium ChannelsSulfonamidesKv Channel-Interacting ProteinsComputer SimulationTerfenadineTetrodotoxinCisaprideCation Transport ProteinsElectrocardiography, AmbulatoryAtrial Fibrillation