Action PotentialsElectrophysiologyMembrane PotentialsPatch-Clamp TechniquesTetrodotoxinElectric StimulationSodium ChannelsCalciumGuinea PigsVentricular FunctionNeuronsPotassium ChannelsNeural ConductionHeartPotassiumHeart Conduction SystemPapillary MusclesAxonsElectric Conductivity4-AminopyridineSynaptic TransmissionMicroelectrodesPyramidal CellsHeart VentriclesDendritesSodiumPurkinje FibersSynapsesPotassium Channel BlockersTetraethylammonium CompoundsRefractory Period, ElectrophysiologicalPotassium Channels, Voltage-GatedAnti-Arrhythmia AgentsMyocytes, CardiacModels, CardiovascularArrhythmias, CardiacSodium Channel BlockersExcitatory Postsynaptic PotentialsTime FactorsIon ChannelsDelayed Rectifier Potassium ChannelsTetraethylammoniumDogsNeurons, AfferentEvoked PotentialsCalcium ChannelsModels, NeurologicalCalcium Channels, L-TypeMyocardiumMyocardial ContractionHeart AtriaRats, Sprague-DawleyIon Channel GatingMotor NeuronsSinoatrial NodeAtrial FunctionVoltage-Sensitive Dye ImagingEndocardiumCalcium SignalingRats, WistarElectrophysiological PhenomenaHippocampusCalcium Channel BlockersNeural InhibitionInterneuronsPericardiumAnuraRabbitsQuinidineComputer SimulationLong QT SyndromeAnimals, NewbornPresynaptic TerminalsEther-A-Go-Go Potassium ChannelsReaction TimeNeurotransmitter AgentsBariumCatsNeocortexCells, CulturedLidocaineMuscle ContractionCesiumGanglia, SpinalNeuromuscular Junctiongamma-Aminobutyric AcidElectrocardiographyVentricular FibrillationDifferential ThresholdShal Potassium ChannelsSotalolCardiac Pacing, ArtificialMusclesAminopyridinesSynaptic PotentialsStrontiumCnidarian VenomsSodium-Calcium ExchangerSensory Receptor CellsDecapodiformes