Heart FailureVentricular Function, LeftHeartStroke VolumeVentricular Dysfunction, LeftHeart RateVentricular Function, RightEchocardiographyHeart VentriclesVentricular FunctionMyocardiumMyocytes, CardiacMyocardial ContractionCardiac Output, LowHemodynamicsMyocardial InfarctionCardiomyopathy, DilatedHeart DiseasesCardiac OutputVentricular RemodelingSystoleHeart Function TestsHeart Failure, SystolicCardiac Pacing, ArtificialTime FactorsCardiomyopathiesTreatment OutcomeDiastoleNatriuretic Peptide, BrainElectrocardiographyCardiotonic AgentsFollow-Up StudiesProspective StudiesHeart TransplantationArrhythmias, CardiacVentricular Dysfunction, RightHeart Failure, DiastolicMyocardial IschemiaAdrenergic beta-AntagonistsEchocardiography, DopplerRadionuclide VentriculographyCardiac CatheterizationGated Blood-Pool ImagingCardiomegalyChronic DiseaseCardiac Surgical ProceduresExercise TestHeart Defects, CongenitalDeath, Sudden, CardiacHypertrophy, Left VentricularPredictive Value of TestsPrognosisCardiac VolumeVentricular PressureBlood PressureHeart AtriaCoronary DiseaseDogsVentricular DysfunctionRisk FactorsCoronary CirculationRadionuclide AngiographyDisease Models, AnimalTreatment FailureRetrospective StudiesPropanolaminesAngiotensin-Converting Enzyme InhibitorsSeverity of Illness IndexDobutamineHeart-Assist DevicesBiological MarkersPacemaker, ArtificialMagnetic Resonance Imaging, CineCardiac Resynchronization TherapyTomography, Emission-Computed, Single-PhotonMitral Valve InsufficiencyRisk AssessmentAtrial Natriuretic FactorExercise ToleranceOxygen ConsumptionMyocarditisFibrosisCarbazolesFetal HeartCoronary Artery BypassCardiovascular AgentsMetoprololVentriculography, First-PassDiureticsEchocardiography, Doppler, PulsedHeart ValvesMyocardial Reperfusion InjuryHospitalizationCoronary AngiographyEchocardiography, Doppler, ColorAtrial FibrillationHeart BlockAtrial Function, LeftDefibrillators, ImplantableSurvival Analysis