Coronary SinusCoronary VesselsCoronary CirculationCoronary AngiographyCoronary Artery DiseasePericardiumCoronary StenosisCoronary VasospasmSinus of ValsalvaAngioplasty, Balloon, CoronaryCoronary DiseaseDogsCardiac Pacing, ArtificialElectrocardiographyVasodilationCardiac CatheterizationCoronary Artery BypassCranial SinusesMaxillary SinusBlood Flow VelocityNitroglycerinErgonovineVasodilator AgentsParanasal SinusesVasomotor SystemCavernous SinusAcetylcholineHemodynamicsCoronary Vessel AnomaliesMicrocirculationCoronary ThrombosisMyocardial IschemiaMyocardial InfarctionCoronary AneurysmVena Cava, SuperiorAdenosineCarotid SinusPapaverineMyocardiumVascular ResistanceHeart AtriaCatheter AblationFrontal SinusAngina Pectoris, VariantEndothelium, VascularMyocardial BridgingParanasal Sinus DiseasesMicrovascular Anginaomega-N-MethylarginineSphenoid SinusPacemaker, ArtificialAngina PectorisHeart Conduction SystemSwineChest PainUltrasonography, InterventionalEchocardiographyIsosorbide DinitrateCollateral CirculationTreatment OutcomeAtrial FibrillationAtrioventricular NodeElectrophysiologic Techniques, CardiacRisk FactorsSinus Thrombosis, IntracranialProspective StudiesModels, CardiovascularHeart Arrest, InducedNitric OxideVasoconstrictionSick Sinus SyndromeAtrial FlutterHyperemiaHeartEthmoid SinusTachycardia, Sinoatrial Nodal ReentryCoronary RestenosisBlood PressureRegional Blood FlowBundle of HisTime FactorsCoronary OcclusionVentricular Dysfunction, LeftElectrodes, ImplantedFollow-Up StudiesHeart Rate15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidAtrial FunctionEchocardiography, DopplerArteriesCardiac Resynchronization Therapy DevicesPercutaneous Coronary InterventionExercise TestCardiac CathetersTomography, X-Ray ComputedParanasal Sinus NeoplasmsPhlebographySeverity of Illness IndexTachycardia, Atrioventricular Nodal ReentryHeart Ventricles