Heart RateFluorescence Recovery After PhotobleachingModels, BiologicalKineticsAlgorithmsHeartHeart Rate, FetalHeart FailureBlood PressureAutonomic Nervous SystemHeart DiseasesHemodynamicsHeart TransplantationHeart Defects, CongenitalFetal HeartTime FactorsSympathetic Nervous SystemElectrocardiography, AmbulatoryElectrocardiographyBaroreflexHeart AtriaAdrenergic beta-AntagonistsExercise TestMyocardial ContractionHeart ValvesMyocardiumOxygen ConsumptionHeart BlockDogsHeart Function TestsTelemetryParasympathetic Nervous SystemBradycardiaStroke VolumeRespirationVentricular Function, LeftPropranololMyocardial IschemiaCardiovascular Physiological PhenomenaProspective StudiesExerciseTachycardiaPhysical ExertionCoronary DiseaseCardiovascular SystemCardiac OutputRestAtropinePropanolaminesCardiotonic AgentsPressoreceptorsHeart Arrest, InducedEchocardiographyNorepinephrineDose-Response Relationship, DrugSinoatrial NodeRisk FactorsReference ValuesMyocardial InfarctionModels, CardiovascularDouble-Blind MethodAutonomic Nervous System DiseasesReflexSignal Processing, Computer-AssistedPostureReproducibility of ResultsRats, WistarTreatment OutcomeMyocytes, CardiacRats, Sprague-DawleyArrhythmia, SinusCardiac Output, LowPredictive Value of TestsCardiac Pacing, ArtificialFollow-Up StudiesSystoleMetoprololSupine PositionIsoproterenolDiastoleVentricular Dysfunction, LeftBody TemperatureAnalysis of VarianceRegional Blood FlowCardiomyopathy, DilatedEpinephrineCircadian RhythmDisease Models, AnimalBlood Flow VelocityArrhythmias, CardiacCross-Over StudiesOxygenPrognosisHypotensionAnti-Arrhythmia AgentsCardiomegalyFetal MonitoringCatecholaminesComputer SimulationAtenolol