Heart FailureVentricular Function, LeftHeartVentricular Dysfunction, LeftStroke VolumeHeart RateVentricular 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 CatheterizationAdrenergic beta-AntagonistsMyocardial IschemiaEchocardiography, DopplerCardiac Surgical ProceduresHeart Defects, CongenitalChronic DiseaseHypertrophy, Left VentricularExercise TestDeath, Sudden, CardiacRadionuclide VentriculographyVentricular PressureDogsBlood PressureCardiac 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 ArrestDigoxin