Sinoatrial NodeSinoatrial BlockTachycardia, Sinoatrial Nodal ReentryLymph NodesBiological ClocksArrhythmias, CardiacAtrioventricular NodeHeart AtriaBradycardiaHeart RateHeart Conduction SystemAction PotentialsElectrocardiographyRabbitsAtrial FunctionHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsModels, CardiovascularArrhythmia, SinusDeath, Sudden, CardiacAnti-Arrhythmia AgentsTachycardia, VentricularCyclic Nucleotide-Gated Cation ChannelsVagus NerveSick Sinus SyndromeCalcium Channels, L-TypeCardiac Pacing, ArtificialElectrophysiologyHeartConnexin 43DogsAtrial Function, RightElectrophysiologic Techniques, CardiacHeart BlockMembrane PotentialsIsoproterenolMyocytes, CardiacCalcium Channels, T-TypeConnexinsDefibrillators, ImplantableTachycardia, SinusPotassium ChannelsIon ChannelsPatch-Clamp TechniquesVentricular FibrillationElectrocardiography, AmbulatoryTachycardia, SupraventricularLymph Node ExcisionSodium ChannelsMyoblasts, CardiacGuinea PigsPacemaker, ArtificialMicroelectrodesAminophyllineAutonomic Nervous SystemDelayed Rectifier Potassium ChannelsAdrenergic beta-AgonistsElectrophysiological PhenomenaTachycardiaBenzazepinesSentinel Lymph Node BiopsyHeart VentriclesComputer SimulationCardiac MyosinsTime FactorsCircadian RhythmMyocardial ContractionDeath, SuddenRyanodineNAV1.5 Voltage-Gated Sodium ChannelCardiotonic AgentsRyanodine Receptor Calcium Release ChannelCalciumAging, PrematureSyncopeSarcoplasmic ReticulumAcetylcholineSodium-Calcium ExchangerBrugada SyndromeNatriuretic Peptide, C-TypeParasympathetic Nervous SystemCalcium SignalingAtrial FibrillationMyocardiumAtropineIon Channel GatingLymphatic MetastasisMice, KnockoutPhosphodiesterase 3 Inhibitors