Arrhythmias, CardiacSinoatrial NodeSick Sinus SyndromeArrhythmia, SinusCranial SinusesMaxillary SinusParanasal SinusesSinoatrial BlockSinus of ValsalvaCavernous SinusLymph NodesTachycardia, SinusCarotid SinusFrontal SinusParanasal Sinus DiseasesSphenoid SinusElectrocardiographyCoronary SinusCardiac Pacing, ArtificialAtrioventricular NodeBradycardiaHeart Conduction SystemSinus Thrombosis, IntracranialPacemaker, ArtificialEthmoid SinusHeart AtriaAtrial FibrillationHeart RateHeart BlockAnti-Arrhythmia AgentsParanasal Sinus NeoplasmsTachycardiaSinus Arrest, CardiacElectrocardiography, AmbulatoryCatheter AblationMaxillary Sinus NeoplasmsTachycardia, VentricularAtrial SeptumDogsAtrioventricular BlockElectrophysiologic Techniques, CardiacSyncopePilonidal SinusTachycardia, SupraventricularTransverse SinusesHeartAtrial FlutterAtrial FunctionVentricular FibrillationSuperior Sagittal SinusLymph Node ExcisionRefractory Period, ElectrophysiologicalElectrophysiologyAction PotentialsVentricular Premature ComplexesBundle of HisCardiac ElectrophysiologyTime FactorsAutonomic Nerve BlockMitochondrial SizeHeart VentriclesSentinel Lymph Node BiopsyNAV1.5 Voltage-Gated Sodium ChannelTreatment OutcomeFollow-Up StudiesCardiac Complexes, PrematureAtrial Function, RightBody Surface Potential MappingAutonomic Nervous SystemVagus NerveMyocardiumElectric CountershockPressoreceptorsModels, CardiovascularTachycardia, Sinoatrial Nodal ReentryCerebral VeinsDeath, Sudden, CardiacParasympathetic Nervous SystemAtropineVena Cava, SuperiorLong QT SyndromePulmonary VeinsAmiodaroneLymphatic MetastasisDefibrillators, ImplantableHyperpolarization-Activated Cyclic Nucleotide-Gated ChannelsRetrospective StudiesPropranololBiological ClocksProspective StudiesPetrosal Sinus SamplingEchocardiographyFlecainideBlood PressureRabbitsLateral Sinus ThrombosisHeart TransplantationCyclic Nucleotide-Gated Cation ChannelsHistiocytosis, SinusReflex