Arrhythmias, CardiacHeartHeart RateCranial SinusesMaxillary SinusArrhythmia, SinusParanasal SinusesSinus of ValsalvaCavernous SinusAnterior ChamberCarotid SinusFrontal SinusElectrocardiographyParanasal Sinus DiseasesSphenoid SinusCoronary SinusHeart FailureAnti-Arrhythmia AgentsTachycardia, VentricularSick Sinus SyndromeHeart AtriaHeart DiseasesSinus Thrombosis, IntracranialVentricular FibrillationEthmoid SinusHeart Defects, CongenitalAtrial FibrillationTachycardia, SinusHeart Conduction SystemHeart BlockVentricular Premature ComplexesTachycardiaHeart TransplantationElectrocardiography, AmbulatoryCardiac Pacing, ArtificialMyocardiumParanasal Sinus NeoplasmsFetal HeartDogsTime FactorsUpper ExtremityCardiac Complexes, PrematureCatheter AblationDeath, Sudden, CardiacSinoatrial NodeDiffusion Chambers, CultureTachycardia, SupraventricularMyocytes, CardiacMyocardial IschemiaLong QT SyndromeAtrial FlutterMaxillary Sinus NeoplasmsHeart ValvesHeart VentriclesMyocardial ContractionDefibrillators, ImplantableElectric CountershockTreatment OutcomeFollow-Up StudiesPacemaker, ArtificialPilonidal SinusElectrophysiologic Techniques, CardiacBradycardiaMyocardial InfarctionModels, CardiovascularEchocardiographyAtmosphere Exposure ChambersTransverse SinusesHemodynamicsVentricular DysfunctionAction PotentialsProspective StudiesMyocardial Reperfusion InjuryRisk FactorsSuperior Sagittal SinusHeart Function TestsCardiomyopathiesAtrioventricular NodeSyncopeCardiomyopathy, DilatedVentricular Function, LeftFlecainidePerfusionAutonomic Nervous SystemCoronary DiseaseAdrenergic beta-AntagonistsNAV1.5 Voltage-Gated Sodium ChannelHeart Arrest, InducedRetrospective StudiesDisease Models, AnimalStroke VolumeTorsades de PointesAmiodaroneDigitalis GlycosidesUpper Gastrointestinal TractHeart ArrestBody Surface Potential MappingCardiotonic AgentsElectrophysiologyHeart Septum