Cardiac Resynchronization TherapyCardiac Resynchronization Therapy DevicesCardiac Pacing, ArtificialHeart FailurePacemaker, ArtificialBundle-Branch BlockDefibrillators, ImplantableVentricular Dysfunction, LeftCoronary SinusVentricular RemodelingStroke VolumeHeart VentriclesTreatment OutcomeArrhythmias, CardiacElectrocardiographyEchocardiographyCardiomyopathy, DilatedVentricular Function, LeftProsthesis ImplantationElectrodes, ImplantedHeart Conduction SystemEchocardiography, DopplerMyocytes, CardiacCardiac OutputVentricular DysfunctionCardiac Output, LowCardiomyopathiesElectric CountershockHeartDeath, Sudden, CardiacMyocardial ContractionCardiography, ImpedanceCicatrixElectrophysiologic Techniques, CardiacFollow-Up StudiesTime FactorsCardiac Surgical ProceduresAtrioventricular NodeMitral Valve InsufficiencyProspective StudiesHemodynamicsEchocardiography, Doppler, ColorPredictive Value of TestsVentricular Function, RightCardiac Imaging TechniquesPatient SelectionSystoleEchocardiography, Three-DimensionalMyocardial IschemiaVentricular Dysfunction, RightDextrocardiaHeart AtriaEquipment FailureCardiac CatheterizationBody Surface Potential MappingMyocardiumHeart RateElectric InjuriesTachycardia, VentricularHeart DiseasesSeverity of Illness IndexTherapy, Computer-AssistedAtrial FibrillationCardiac VolumeAtrioventricular BlockRetrospective StudiesEndocardiumDogsPhlebographyModels, CardiovascularEchocardiography, Doppler, PulsedGated Blood-Pool ImagingPrognosisHeart Function TestsRecovery of FunctionFluoroscopyKaplan-Meier EstimateNatriuretic Peptide, BrainEquipment DesignVentricular FunctionReproducibility of ResultsVentricular FibrillationExercise TestRisk AssessmentVentricular PressureSensitivity and SpecificityCardiomegalyCardiac TamponadeTachycardia, Ectopic AtrialFeasibility StudiesPericardiumMagnetic Resonance Imaging, CineExercise ToleranceHeart BlockHeart Failure, SystolicHeart-Assist DevicesSurvival AnalysisPhrenic NerveRisk FactorsHospitalization