Ventricular Function, LeftHeartVentricular Function, RightVentricular Dysfunction, LeftHeart RateStroke VolumeVentricular FunctionHeart FailureEchocardiographyHeart VentriclesMyocardial ContractionMyocardial InfarctionHemodynamicsMyocardiumSystoleHeart DiseasesVentricular Dysfunction, RightDiastoleHeart Function TestsRadionuclide VentriculographyHeart Defects, CongenitalGated Blood-Pool ImagingHeart TransplantationCardiomyopathy, DilatedCoronary DiseaseEchocardiography, DopplerHypertrophy, Left VentricularElectrocardiographyMyocardial IschemiaTime FactorsRadionuclide AngiographyVentricular RemodelingCoronary CirculationCardiomyopathiesHeart AtriaCardiac CatheterizationVentricular PressureCardiotonic AgentsFollow-Up StudiesTreatment OutcomeCardiac VolumeExercise TestProspective StudiesCineangiographyCardiac Pacing, ArtificialVentriculography, First-PassDobutamineVentricular DysfunctionCardiac OutputDogsEchocardiography, Doppler, PulsedHeart BlockMyocardial Reperfusion InjuryAngiocardiographyAtrial Function, LeftHeart Arrest, InducedFetal HeartHeart ValvesPredictive Value of TestsBlood PressureAdrenergic beta-AntagonistsMyocardial ReperfusionMagnetic Resonance Imaging, CineEchocardiography, Doppler, ColorMyocytes, CardiacPhonocardiographyMitral Valve InsufficiencyTomography, Emission-Computed, Single-PhotonCardiac Output, LowCoronary AngiographyCoronary Artery BypassNatriuretic Peptide, BrainHeart SeptumHeart Valve ProsthesisAortic Valve StenosisCardiomegalyTricuspid ValvePrognosisAngina PectorisDisease Models, AnimalMitral ValveGold RadioisotopesCardiac Surgical ProceduresCoronary VesselsEndocardiumPulmonary ArteryChronic DiseaseTechnetium Tc 99m SestamibiAngioplasty, Balloon, CoronaryRecovery of FunctionHeart AneurysmMyocarditisRisk FactorsHeart Valve Prosthesis ImplantationEchocardiography, StressOxygen ConsumptionTetralogy of FallotPacemaker, ArtificialHypoplastic Left Heart SyndromeBlood Flow Velocity