Sinoatrial NodeSinoatrial BlockHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsTachycardia, Sinoatrial Nodal ReentryLymph NodesCyclic Nucleotide-Gated Cation ChannelsBiological ClocksAtrioventricular NodeBradycardiaHeart AtriaHeart RateAction PotentialsRabbitsAtrial FunctionHeart Conduction SystemArrhythmia, SinusPotassium ChannelsModels, CardiovascularIon ChannelsVagus NerveSick Sinus SyndromeElectrophysiologyMembrane PotentialsAtrial Function, RightCalcium Channels, L-TypeHeart BlockCalcium Channels, T-TypeConnexinsHeartDogsPatch-Clamp TechniquesTachycardia, SinusElectrocardiographyIsoproterenolConnexin 43Myocytes, CardiacCardiac Pacing, ArtificialLymph Node ExcisionBenzazepinesMyoblasts, CardiacElectrophysiological PhenomenaMicroelectrodesAminophyllineAdrenergic beta-AgonistsIon Channel GatingDelayed Rectifier Potassium ChannelsGuinea PigsSentinel Lymph Node BiopsyCardiac MyosinsArrhythmias, CardiacPacemaker, ArtificialCardiotonic AgentsSodium ChannelsRyanodineComputer SimulationAutonomic Nervous SystemAging, PrematureAnti-Arrhythmia AgentsHydrogen CyanideTachycardia, SupraventricularSarcoplasmic ReticulumAcetylcholineSodium-Calcium ExchangerNatriuretic Peptide, C-TypeParasympathetic Nervous SystemCalciumCalcium SignalingAtropineElectrophysiologic Techniques, CardiacMyocardial ContractionMuscle ProteinsRyanodine Receptor Calcium Release ChannelLymphatic MetastasisPhosphodiesterase 3 Inhibitors