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, ColorPatient SelectionPredictive Value of TestsElectrophysiologic Techniques, CardiacProspective StudiesVentricular Function, RightPractice Guidelines as TopicMyocardial ContractionEchocardiography, Three-DimensionalElectric InjuriesTime FactorsDextrocardiaSystoleVentricular Dysfunction, RightSeverity of Illness IndexPhlebographyCardiac Imaging TechniquesTherapy, Computer-AssistedMyocardial IschemiaEquipment FailureBody Surface Potential MappingHemodynamicsAtrial FibrillationEchocardiography, Doppler, PulsedTachycardia, VentricularHeart AtriaRecovery of FunctionKaplan-Meier EstimateFluoroscopyRetrospective StudiesCardiac OutputGated Blood-Pool ImagingAtrioventricular BlockDeath, Sudden, CardiacEndocardiumPrognosisReproducibility of ResultsSensitivity and SpecificityEquipment DesignPhrenic NerveNatriuretic Peptide, BrainExercise TestRisk AssessmentFeasibility StudiesRandomized Controlled Trials as TopicGuidelines as TopicTreatment FailureVena Cava, SuperiorExercise ToleranceHeart Failure, SystolicHeart RateGuideline AdherencePsychological TechniquesVentricular FibrillationHeart-Assist DevicesObserver VariationMagnetic Resonance Imaging, CineHeartCardiac VolumeHospitalizationDiagnostic ImagingHeart Function TestsSingle-Blind MethodDogsSurvival AnalysisMulticenter Studies as TopicVentricular PressurePericardiumRisk Factors