Heart RateBlood PressureHeartPressureBlood Pressure DeterminationHypertensionBlood Pressure Monitoring, AmbulatoryHemodynamicsAntihypertensive AgentsAutonomic Nervous SystemHeart FailureSystoleHydrostatic PressureSympathetic Nervous SystemHeart Rate, FetalBaroreflexTime FactorsBlood Pressure MonitorsHypotensionDiastoleHeart DiseasesSyncope, VasovagalCardiovascular SystemArterial PressureReninRats, Inbred SHRPulseCardiac OutputElectrocardiographyAdrenergic beta-AntagonistsProspective StudiesPressoreceptorsVascular ResistanceCircadian RhythmSupine PositionDogsTelemetryCardiovascular Physiological PhenomenaHeart TransplantationNorepinephrineRisk FactorsRegional Blood FlowHeart Defects, CongenitalIntracranial PressureIntraocular PressureRespirationCardiovascular DiseasesKidneyTransducers, PressureExercise TestDouble-Blind MethodFollow-Up StudiesFetal HeartReference ValuesMyocardiumExercisePropranololElectrocardiography, AmbulatoryReflexBlood Flow VelocityPostureRats, Sprague-DawleyMyocardial ContractionAnalysis of VarianceBradycardiaOxygen ConsumptionBody WeightVenous PressureRats, Inbred WKYDose-Response Relationship, DrugSyncopeVentricular PressurePhysical ExertionAngiotensin IIVentricular Function, LeftHeart AtriaSphygmomanometersTreatment OutcomeCentral Venous PressureAtmospheric PressureRestEchocardiographyCross-Over StudiesCoronary DiseasePhenylephrineAtenololMonitoring, PhysiologicAutonomic Nervous System DiseasesSodium Chloride, DietaryRegression AnalysisAge FactorsPropanolaminesHypertension, RenalAir PressureArteriesSodium, DietaryRenin-Angiotensin SystemValsalva ManeuverRats, WistarTachycardia