Coronary SinusCoronary VesselsCoronary AngiographyCoronary CirculationCoronary Artery DiseaseSinus of ValsalvaAngioplasty, Balloon, CoronaryCoronary StenosisCoronary Artery BypassCranial SinusesMaxillary SinusCoronary DiseaseParanasal SinusesCardiac Pacing, ArtificialCavernous SinusCoronary Vessel AnomaliesCarotid SinusDogsElectrocardiographyCoronary AneurysmVena Cava, SuperiorBedsCoronary VasospasmCardiac CatheterizationHeart AtriaCatheter AblationFrontal SinusParanasal Sinus DiseasesSphenoid SinusHemodynamicsPacemaker, ArtificialBed RestVascular ResistanceHeart Conduction SystemTreatment OutcomeMyocardiumMyocardial InfarctionAtrial FibrillationVasodilationCoronary ThrombosisAtrioventricular NodeElectrophysiologic Techniques, CardiacBlood PressureTime FactorsSinus Thrombosis, IntracranialHeartRegional Blood FlowHeart Arrest, InducedVasodilator AgentsSick Sinus SyndromeAtrial FlutterEthmoid SinusTachycardia, Sinoatrial Nodal ReentryCoronary RestenosisMyocardial IschemiaPerfusionBundle of HisBlood Flow VelocityCoronary OcclusionVeinsElectrodes, ImplantedFollow-Up StudiesVasoconstrictionTomography, X-Ray ComputedAtrial FunctionProspective StudiesSplanchnic CirculationRisk FactorsCardiac Resynchronization Therapy DevicesEndothelium, VascularPercutaneous Coronary InterventionCardiac CathetersParanasal Sinus NeoplasmsPhlebographyTachycardia, Atrioventricular Nodal ReentryHeart VentriclesTachycardia, SupraventricularProsthesis ImplantationAtrial SeptumSinoatrial NodeTachycardia, SinusEchocardiographyHeart RateCoronary Care UnitsMesenteric ArteriesDilatation, PathologicNorepinephrineHeart FailureAdenosineEchocardiography, TransesophagealWolff-Parkinson-White SyndromePulmonary VeinsFeasibility StudiesPredictive Value of TestsBody Surface Potential MappingFluoroscopyStentsOxygen ConsumptionPulmonary CirculationDipyridamole