Sinoatrial NodeAtrioventricular NodeTachycardia, Atrioventricular Nodal ReentryWolff-Parkinson-White SyndromeCatheter AblationHeart Conduction SystemCardiac Pacing, ArtificialSinoatrial BlockTachycardia, ParoxysmalTachycardia, SupraventricularElectrocardiographyNeural ConductionHeart BlockTachycardia, Sinoatrial Nodal ReentryElectrophysiologyLymph NodesHeart AtriaBradycardiaBiological ClocksAction PotentialsAtrial FunctionHeart RateRabbitsModels, CardiovascularRecurrenceHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsArrhythmia, SinusSick Sinus SyndromeVagus NerveCyclic Nucleotide-Gated Cation ChannelsDogsAtrial Function, RightConnexinsHeartConnexin 43Membrane PotentialsFollow-Up StudiesArrhythmias, CardiacCalcium Channels, L-TypePotassium ChannelsIon ChannelsCalcium Channels, T-TypeTachycardia, SinusIsoproterenolMyocytes, CardiacElectrophysiologic Techniques, CardiacSodium ChannelsPatch-Clamp TechniquesAnti-Arrhythmia AgentsMicroelectrodesElectrophysiological PhenomenaGuinea PigsLymph Node ExcisionAminophyllineMyoblasts, CardiacDelayed Rectifier Potassium ChannelsAdrenergic beta-AgonistsComputer SimulationRefractory Period, ElectrophysiologicalBenzazepinesHeart VentriclesElectric StimulationRanvier's NodesSentinel Lymph Node BiopsyTime FactorsAutonomic Nervous SystemCardiotonic AgentsCardiac MyosinsAcetylcholineAtrial FibrillationRyanodineIon Channel GatingPacemaker, ArtificialCalciumMyocardial ContractionBone ConductionAging, PrematureParasympathetic Nervous SystemSarcoplasmic ReticulumAtropineSodium-Calcium ExchangerNatriuretic Peptide, C-TypeMedian NerveCalcium SignalingTachycardiaPapillary MusclesMyocardiumElectric ConductivityT-Box Domain ProteinsAdams-Stokes SyndromeRyanodine Receptor Calcium Release ChannelCell SizeMice, KnockoutLymphatic MetastasisPhosphodiesterase 3 Inhibitors4-Aminopyridine