Heart FailureStroke VolumeVentricular Function, LeftStrokeHeartCardiac OutputHeart RateVentricular Dysfunction, LeftHemodynamicsVentricular Function, RightHeart VentriclesEchocardiographyVentricular FunctionMyocardial ContractionMyocardiumMyocytes, CardiacCardiac Output, LowTime FactorsMyocardial InfarctionSystoleBlood PressureHeart Function TestsHeart DiseasesCardiomyopathy, DilatedTreatment OutcomeDiastoleProspective StudiesVentricular RemodelingCardiac Pacing, ArtificialBlood VolumeEchocardiography, DopplerFollow-Up StudiesElectrocardiographyCardiac VolumeCardiotonic AgentsCardiac CatheterizationCardiomyopathiesExercise TestHeart Failure, SystolicDogsNatriuretic Peptide, BrainVentricular Dysfunction, RightAdrenergic beta-AntagonistsRisk FactorsHeart TransplantationCardiomegalyArrhythmias, CardiacHeart Failure, DiastolicCardiac Surgical ProceduresPredictive Value of TestsVentricular PressureChronic DiseaseHypertrophy, Left VentricularHeart Defects, CongenitalMyocardial IschemiaVascular ResistancePrognosisHeart AtriaOxygen ConsumptionVentricular DysfunctionDisease Models, AnimalCoronary DiseaseRadionuclide VentriculographyGated Blood-Pool ImagingSeverity of Illness IndexRetrospective StudiesCoronary CirculationDeath, Sudden, CardiacCardiography, ImpedanceBrain IschemiaThermodilutionPulmonary Wedge PressureBlood Flow VelocityMagnetic Resonance Imaging, CineRadionuclide AngiographyMitral Valve InsufficiencyFetal HeartCineangiographyDobutamineMagnetic Resonance ImagingExercise TolerancePropanolaminesTreatment FailureReproducibility of ResultsEchocardiography, Doppler, ColorHeart-Assist DevicesAcute DiseaseBiological MarkersRecovery of FunctionPacemaker, ArtificialRisk AssessmentAtrial FibrillationCerebrovascular DisordersModels, CardiovascularAngiotensin-Converting Enzyme InhibitorsEchocardiography, Doppler, PulsedAtrial Natriuretic FactorFluid TherapyCohort StudiesPhysical Exertion