Heart RateHeartHeart Rate, FetalHeart FailureBlood PressureAutonomic Nervous SystemHeart DiseasesHemodynamicsHeart TransplantationHeart Defects, CongenitalElectrocardiographyFetal HeartSympathetic Nervous SystemElectrocardiography, AmbulatoryBaroreflexHeart AtriaAdrenergic beta-AntagonistsExercise TestDogsHeart BlockTime FactorsBradycardiaMyocardiumOxygen ConsumptionHeart ValvesTachycardiaMyocardial ContractionTelemetryParasympathetic Nervous SystemPropranololHeart Function TestsStroke VolumeVentricular Function, LeftCardiac Pacing, ArtificialPhysical ExertionCardiovascular Physiological PhenomenaRespirationCardiac OutputMyocardial IschemiaCardiovascular SystemSinoatrial NodeAtropineExerciseArrhythmias, CardiacPropanolaminesPressoreceptorsCoronary DiseaseArrhythmia, SinusCardiotonic AgentsVentricular Premature ComplexesNorepinephrineModels, CardiovascularHeart Arrest, InducedEchocardiographyReflexRestIsoproterenolMetoprololPostureMyocardial InfarctionAutonomic Nervous System DiseasesCardiac Output, LowAnti-Arrhythmia AgentsProspective StudiesMyocytes, CardiacSignal Processing, Computer-AssistedSupine PositionSystoleEpinephrineDouble-Blind MethodDose-Response Relationship, DrugDiastoleCardiomyopathy, DilatedRisk FactorsBody TemperatureAtenololRegional Blood FlowVentricular Dysfunction, LeftReference ValuesTilt-Table TestCatecholaminesRats, Sprague-DawleyHypotensionPhenylephrineRats, WistarCircadian RhythmFollow-Up StudiesCiliaConsciousnessAnesthesiaAtrial Premature ComplexesFetal MonitoringPulseAdrenergic beta-AgonistsMonitoring, PhysiologicPerfusionCardiomegalyPacemaker, ArtificialCross-Over StudiesBlood Flow Velocity