XamoterolHeart RateDeoxyepinephrineHeart FailureCardiac Output, LowHeartPropanolaminesEnalaprilDouble-Blind MethodHeart Rate, FetalAutonomic Nervous SystemBlood PressureHeart DiseasesHeart TransplantationHemodynamicsHeart Defects, CongenitalFetal HeartSympathetic Nervous SystemElectrocardiography, AmbulatoryTime FactorsBaroreflexHeart AtriaElectrocardiographyAdrenergic beta-AntagonistsExercise TestHeart ValvesMyocardial ContractionMyocardiumOxygen ConsumptionHeart BlockDogsHeart Function TestsParasympathetic Nervous SystemTelemetryBradycardiaExercisePropranololStroke VolumeRespirationPhysical ExertionMyocardial IschemiaVentricular Function, LeftCardiovascular Physiological PhenomenaCoronary DiseaseProspective StudiesTachycardiaRestCardiovascular SystemCardiac OutputAtropinePressoreceptorsRisk FactorsCardiotonic AgentsHeart Arrest, InducedNorepinephrineSinoatrial NodeEchocardiographyDose-Response Relationship, DrugMyocardial InfarctionTreatment OutcomeReflexAutonomic Nervous System DiseasesFollow-Up StudiesMyocytes, CardiacPostureArrhythmia, SinusMetoprololCardiac Pacing, ArtificialRats, Sprague-DawleySupine PositionBody TemperatureIsoproterenolModels, CardiovascularReference ValuesSystoleEpinephrineSeverity of Illness IndexSignal Processing, Computer-AssistedRats, WistarCardiomyopathy, DilatedVentricular Dysfunction, LeftRegional Blood FlowDiastolePredictive Value of TestsCircadian RhythmCross-Over StudiesAtenololHypotensionArrhythmias, CardiacAnalysis of VarianceCardiomegalyCatecholaminesDisease Models, AnimalAnti-Arrhythmia AgentsOxygenTilt-Table TestChronic DiseasePhenylephrineFetal MonitoringReproducibility of Results