Cardiac Resynchronization TherapyCardiac Resynchronization Therapy DevicesCardiac Pacing, ArtificialHeart FailurePacemaker, ArtificialDefibrillators, ImplantableBundle-Branch BlockCoronary SinusVentricular Dysfunction, LeftVentricular RemodelingStroke VolumeTreatment OutcomeHeart VentriclesEchocardiographyProsthesis ImplantationElectrocardiographyElectrodes, ImplantedVentricular Function, LeftCardiomyopathy, DilatedEchocardiography, DopplerHeart Conduction SystemArrhythmias, CardiacCardiac Output, LowCicatrixVentricular DysfunctionElectric CountershockCardiomyopathiesCardiography, ImpedanceMitral Valve InsufficiencyAtrioventricular NodeFollow-Up StudiesEchocardiography, Doppler, ColorPredictive Value of TestsPatient SelectionElectrophysiologic Techniques, CardiacVentricular Function, RightProspective StudiesMyocardial ContractionEchocardiography, Three-DimensionalElectric InjuriesDextrocardiaTime FactorsSystoleVentricular Dysfunction, RightPhlebographyCardiac Imaging TechniquesSeverity of Illness IndexTherapy, Computer-AssistedMyocardial IschemiaEquipment FailureBody Surface Potential MappingHemodynamicsEchocardiography, Doppler, PulsedTachycardia, VentricularAtrial FibrillationHeart AtriaRecovery of FunctionKaplan-Meier EstimateCardiac OutputFluoroscopyGated Blood-Pool ImagingAtrioventricular BlockEndocardiumDeath, Sudden, CardiacRetrospective StudiesPrognosisReproducibility of ResultsEquipment DesignPhrenic NerveSensitivity and SpecificityNatriuretic Peptide, BrainExercise TestFeasibility StudiesTreatment FailureRandomized Controlled Trials as TopicVena Cava, SuperiorRisk AssessmentExercise ToleranceHeart Failure, SystolicHeart RatePsychological TechniquesVentricular FibrillationHeart-Assist DevicesMagnetic Resonance Imaging, CineHeartCardiac VolumeObserver VariationHospitalizationHeart Function TestsDiagnostic ImagingDogsSingle-Blind MethodSurvival AnalysisVentricular PressureMulticenter Studies as TopicPericardiumMyocardial Perfusion ImagingCardiac CatheterizationTomography, Emission-Computed, Single-PhotonMonitoring, Ambulatory