HeartHeart RateHeart FailureHeart DiseasesHeart TransplantationHeart Defects, CongenitalFetal HeartHeart ValvesHeart AtriaHeart BlockMyocardiumHeart Arrest, InducedHeart Function TestsMyocardial ContractionTime FactorsMyocardial IschemiaMyocytes, CardiacHemodynamicsCoronary DiseaseProspective StudiesTreatment OutcomeRisk FactorsVentricular Function, LeftCardiac Output, LowMyocardial InfarctionPerfusionHeart, ArtificialHeart Failure, SystolicCardiomyopathy, DilatedFollow-Up StudiesCardiomegalyEchocardiographyStroke VolumeHeart Rate, FetalCardiotonic AgentsHeart SeptumHeart InjuriesCardiomyopathiesRheumatic Heart DiseaseHeart ArrestMyocardial Reperfusion InjuryHeart Valve ProsthesisVentricular Dysfunction, LeftDogsAdrenergic beta-AntagonistsHeart Failure, DiastolicAmerican Heart AssociationRetrospective StudiesVentricular RemodelingChronic DiseaseOxygen ConsumptionRats, Sprague-DawleyDisease Models, AnimalReproducibility of ResultsCardiac Pacing, ArtificialExercise TestRats, WistarAutonomic Nervous SystemHypoplastic Left Heart SyndromeHeart Septal DefectsHeart NeoplasmsNatriuretic Peptide, BrainPredictive Value of TestsCohort StudiesNational Heart, Lung, and Blood Institute (U.S.)Models, CardiovascularVentricular PressureSensitivity and SpecificityBiological MarkersSympathetic Nervous SystemPrognosisRisk AssessmentAge FactorsSeverity of Illness IndexSystoleDouble-Blind MethodRabbitsUnited StatesEndocardiumDose-Response Relationship, DrugDiastoleCase-Control StudiesReference ValuesCardiovascular DiseasesIsoproterenolPropanolaminesCalciumRNA, MessengerInfant, NewbornHeart Septal Defects, VentricularElectrocardiography, AmbulatoryIschemic Preconditioning, MyocardialMyocarditisIncidenceHeart-Assist DevicesNorepinephrineSex FactorsAnti-Arrhythmia AgentsAlgorithmsProportional Hazards Models