Heart FailureHeart RateHeartVentricular Function, LeftAdrenergic beta-AntagonistsBlood PressureVentricular Dysfunction, LeftSympathetic Nervous SystemStroke VolumeVentricular Function, RightEchocardiographyHeart VentriclesVentricular FunctionMyocytes, CardiacMyocardiumMyocardial ContractionCardiac Output, LowHemodynamicsMyocardial InfarctionCardiac OutputHeart DiseasesCardiomyopathy, DilatedVentricular RemodelingSystoleHeart Function TestsCardiac Pacing, ArtificialHeart Failure, SystolicTime FactorsCardiomyopathiesDiastoleTreatment OutcomeElectrocardiographyCardiotonic AgentsHeart TransplantationNatriuretic Peptide, BrainHeart Failure, DiastolicArrhythmias, CardiacCardiomegalyVentricular Dysfunction, RightFollow-Up StudiesProspective StudiesCardiac CatheterizationMyocardial IschemiaEchocardiography, DopplerCardiac Surgical ProceduresHeart Defects, CongenitalChronic DiseaseHypertrophy, Left VentricularExercise TestDeath, Sudden, CardiacRadionuclide VentriculographyVentricular PressureDogsCardiac VolumeHeart AtriaCoronary DiseasePrognosisVentricular DysfunctionPredictive Value of TestsTreatment FailureDisease Models, AnimalCoronary CirculationGated Blood-Pool ImagingRisk FactorsHeart-Assist DevicesRadionuclide AngiographyAngiotensin-Converting Enzyme InhibitorsRetrospective StudiesPropanolaminesSeverity of Illness IndexBiological MarkersDobutamineExercise TolerancePacemaker, ArtificialOxygen ConsumptionAtrial Natriuretic FactorFetal HeartFibrosisMyocarditisMitral Valve InsufficiencyDiureticsHeart ValvesMyocardial Reperfusion InjuryCardiac Resynchronization TherapyMagnetic Resonance Imaging, CineHeart BlockMetoprololRisk AssessmentCardiovascular AgentsEchocardiography, Doppler, PulsedAtrial Function, LeftCoronary Artery BypassEchocardiography, Doppler, ColorHospitalizationAtrial FibrillationPulmonary Wedge PressureCarbazolesRats, Sprague-DawleyCineangiographyHeart Arrest