Ventricular Dysfunction, LeftVentricular DysfunctionVentricular Dysfunction, RightStroke VolumeVentricular Function, LeftEchocardiographyHeart FailureCardiomyopathiesMyocardial InfarctionHemodynamicsNatriuretic Peptide, BrainElectrocardiographyMyocardial ContractionMyocardial StunningDobutamineVentricular RemodelingRadionuclide VentriculographyMyocardiumSystoleHeartHeart VentriclesCardiomyopathy, DilatedMyocardial IschemiaCardiotonic AgentsAngiotensin-Converting Enzyme InhibitorsEnalaprilMitral Valve InsufficiencyTakotsubo CardiomyopathyEchocardiography, DopplerDiastoleTreatment OutcomeFollow-Up StudiesHypertrophy, Left VentricularThallium RadioisotopesPrognosisTomography, Emission-Computed, Single-PhotonCoronary Artery BypassCoronary DiseaseExercise TestTime FactorsPredictive Value of TestsCardiac Output, LowProspective StudiesTissue SurvivalMyocardial RevascularizationCoronary CirculationHeart DiseasesDefibrillators, ImplantableChronic DiseaseAtrial Natriuretic FactorSeverity of Illness IndexBiological MarkersCardiac Pacing, ArtificialArrhythmias, CardiacRisk FactorsVentricular PressureHeart RateAortic Valve StenosisHeart Function TestsRetrospective StudiesDogsCardiac CatheterizationBlood PressureTachycardia, VentricularCardiac VolumeDisease Models, AnimalAortic ValveAdrenergic beta-AntagonistsCoronary AngiographyDeath, Sudden, CardiacCardiac OutputMitral ValveCoronary Artery DiseaseGated Blood-Pool ImagingErectile DysfunctionSensitivity and SpecificityEchocardiography, StressPulmonary Wedge PressureRisk AssessmentIntra-Aortic Balloon PumpingSurvival RateExercise ToleranceTechnetium Tc 99m SestamibiRadionuclide AngiographyEndocardial FibroelastosisHeart AtriaCardiomegalySurvival AnalysisAnti-Arrhythmia AgentsVasodilator Agents3-IodobenzylguanidineAtrioventricular BlockHeart Valve ProsthesisMyocarditisMilrinoneDouble-Blind MethodAtrial FibrillationFibrosisCardiopulmonary BypassRadiopharmaceuticals