Sinoatrial NodeSinoatrial BlockTachycardia, Sinoatrial Nodal ReentryLymph NodesAtrioventricular NodeBiological ClocksBradycardiaHeart AtriaHeart RateRabbitsAction PotentialsAtrial FunctionHeart Conduction SystemHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsArrhythmia, SinusModels, CardiovascularVagus NerveCyclic Nucleotide-Gated Cation ChannelsSick Sinus SyndromeAtrial Function, RightHeartCalcium Channels, L-TypeHeart BlockElectrophysiologyElectrocardiographyMembrane PotentialsDogsConnexinsPotassium ChannelsCalcium Channels, T-TypeTachycardia, SinusIsoproterenolIon ChannelsMyocytes, CardiacConnexin 43Cardiac Pacing, ArtificialErectile DysfunctionVentricular Dysfunction, LeftPatch-Clamp TechniquesLymph Node ExcisionMyoblasts, CardiacMicroelectrodesAminophyllineAdrenergic beta-AgonistsDelayed Rectifier Potassium ChannelsElectrophysiological PhenomenaAcetylcholineGuinea PigsCardiotonic AgentsBenzazepinesArrhythmias, CardiacAutonomic Nervous SystemSentinel Lymph Node BiopsyMyocardial ContractionCardiac MyosinsPacemaker, ArtificialAging, PrematureSodium ChannelsRyanodineAnti-Arrhythmia AgentsCalciumTime FactorsSodium-Calcium ExchangerSarcoplasmic ReticulumParasympathetic Nervous SystemComputer SimulationTachycardia, SupraventricularCalcium SignalingNatriuretic Peptide, C-TypeMice, KnockoutAtropineMyocardiumElectrophysiologic Techniques, CardiacIon Channel GatingRyanodine Receptor Calcium Release ChannelHeart VentriclesPhosphodiesterase 3 InhibitorsLymphatic MetastasisCell Size