Heart FailureVentricular Dysfunction, LeftStroke VolumeVentricular Function, LeftDefibrillators, ImplantableCardiac Resynchronization TherapyCardiac Pacing, ArtificialNatriuretic Peptide, BrainDouble-Blind MethodTreatment OutcomeHeartVentricular DysfunctionFollow-Up StudiesVentricular Dysfunction, RightHeart RateEchocardiographyCardiac Output, LowElectrocardiographyMyocardiumProspective StudiesHemodynamicsSeverity of Illness IndexCardiomyopathy, DilatedHeart Failure, SystolicVentricular RemodelingMyocardial ContractionCardiomyopathiesMyocardial InfarctionHeart DiseasesHeart VentriclesCardiotonic AgentsChronic DiseaseTime FactorsSystoleHeart Failure, DiastolicQuality of LifeMyocardial IschemiaDiastolePrognosisAdrenergic beta-AntagonistsAngiotensin-Converting Enzyme InhibitorsHypertrophy, Left VentricularHeart TransplantationHeart Function TestsRadionuclide VentriculographyExercise TestPredictive Value of TestsEchocardiography, DopplerRisk FactorsBiological MarkersDisease Models, AnimalHeart AtriaMyocytes, CardiacDobutamineCardiomegalyVentricular PressureDogsRetrospective StudiesHeart Defects, CongenitalCoronary DiseaseAtrial Natriuretic FactorTreatment FailureHeart-Assist DevicesBlood PressureMyocardial StunningMitral Valve InsufficiencyEnalaprilDiureticsArrhythmias, CardiacVentricular Function, RightPropanolaminesErectile DysfunctionRisk AssessmentPulmonary Wedge PressureHospitalizationExercise ToleranceCardiac CatheterizationVasodilator AgentsSurvival AnalysisSurvival RateFibrosisCoronary CirculationCardiac VolumeTakotsubo CardiomyopathyProportional Hazards ModelsCardiac OutputAcute DiseaseDeath, Sudden, CardiacOxygen ConsumptionCoronary Artery BypassAtrial FibrillationAnti-Arrhythmia AgentsTomography, Emission-Computed, Single-PhotonAtrial Function, LeftCardiovascular AgentsMyocarditisHeart BlockDigoxinTachycardia, VentricularCohort Studies