Heart-Assist DevicesVentricular Function, LeftVentricular Function, RightHeart FailureVentricular Dysfunction, LeftHeart TransplantationStroke VolumeVentricular FunctionHeart VentriclesProsthesis ImplantationVentricular Dysfunction, RightHemodynamicsEchocardiographyShock, CardiogenicCardiomyopathy, DilatedEquipment DesignTreatment OutcomeDevice RemovalMyocardial ContractionMyocardial InfarctionCardiomyopathiesProsthesis DesignAssisted CirculationHeartTime FactorsMyocardiumSystoleExtracorporeal Membrane OxygenationIntra-Aortic Balloon PumpingDiastoleEquipment FailureRadionuclide VentriculographyEchocardiography, DopplerVentricular RemodelingEquipment SafetyFollow-Up StudiesElectrocardiographyDevice ApprovalGated Blood-Pool ImagingCardiac CatheterizationRetrospective StudiesCardiac OutputVentricular PressureRadionuclide AngiographyHeart, ArtificialCardiac Surgical ProceduresProspective StudiesHeart DiseasesCoronary CirculationHeart Function TestsHypertrophy, Left VentricularMyocardial IschemiaRecovery of FunctionMiniaturizationHeart RateBlood PressureCardiotonic AgentsPhonocardiographyEchocardiography, TransesophagealPredictive Value of TestsHydrodynamicsExercise TestCineangiographyCoronary DiseaseBiomedical EngineeringCardiac VolumeMitral Valve InsufficiencyCompassionate Use TrialsVentriculography, First-PassCoronary Artery BypassSelf-Help DevicesCardiac Output, LowSeverity of Illness IndexCoronary AngiographyEchocardiography, Doppler, PulsedWaiting ListsPulsatile FlowMyocarditisDobutamineCounterpulsationAngiocardiographyOxygenatorsFeasibility StudiesAtrial Function, LeftPostoperative ComplicationsAngioplasty, Balloon, CoronaryPulmonary ArteryCardiac Pacing, ArtificialHeart Valve Prosthesis ImplantationCardiopulmonary BypassCardiovascular AgentsVentricular DysfunctionMyocytes, CardiacRisk AssessmentEchocardiography, Doppler, ColorOxygenators, MembraneMagnetic Resonance Imaging, CinePrognosisTomography, Emission-Computed, Single-PhotonSurvival Rate