Echocardiography Guided Cardiac Resynchronization Therapy (EchoCRT)

Inclusion Criteria: * Men and women 18 years of age or older. * Understand the nature of the procedure. * Give written informed consent. * Willing and able to complete all testing required by the clinical protocol. * Indication for an implantable cardioverter defibrillator (ICD). * NYHA class III-IV within the last three months prior to enrollment and at baseline (at baseline only: also Stage C according to ACC/AHA guidelines). * Stable optimal pharmacologic therapy for HF. * An ejection fraction ≤ 35% within one year prior to enrollment and confirmed on the baseline echocardiogram. * Increased left ventricular dimension, defined as LVEDD ≥ 55 mm. * Resting QRS duration \< 130 ms evidenced by a historical 12-lead ECG prior to enrollment and at baseline. * Ventricular dyssynchrony assessed by echocardiography locally and confirmed by the echo core lab. One of the two following criteria has to be present to include the subject in the study: * Intra-left ventricular dyssynchrony measured by color Tissue Doppler Imaging (TDI) with an opposing wall delay of ≥ 80 ms in the 4-chamber or apical long-axis view. * Speckle-tracking radial strain septal-posterior wall delay ≥ 130 ms. Exclusion Criteria: * Implanted pacemaker or defibrillator with \>10% ventricular pacing, as demonstrated by device statistics averaged over at least the last three months prior to enrollment. * Women who are pregnant, lactating, or planning to become pregnant during the course of the trial. * Bradycardia pacing indication. * Surgically correctable primary valvular heart disease, i.e. aortic stenosis, torn cordae, or flail segment. * Coronary artery bypass graft surgery or percutaneous coronary intervention (balloon and/or stent angioplasty) within the past 3 months prior to enrollment. * Enzyme-positive myocardial infarction within the past 3 months prior to enrollment. * Angiographic evidence of coronary disease, candidates for coronary revascularization likely to undergo coronary artery bypass graft surgery or percutaneous coronary intervention in the next 3 months. * Irreversible brain damage from preexisting cerebral disease. * Reversible non-ischemic cardiomyopathy such as acute viral myocarditis. * Permanent second or third degree heart block. * Chagas disease. * Persistent or paroxysmal atrial fibrillation within one month prior to enrollment. * Expected to receive heart transplantation within six months. * Current inotropic therapy. * Acutely decompensated heart failure. * Contrast dye allergy and unable or unwilling to undergo pretreatment with steroids and/or diphenhydramine. * Life expectancy of less than six months. * Presence of any disease, other than the subject's cardiac disease associated with a reduced likelihood of survival for the duration of the trial, (e.g. cancer). * Significant renal insufficiency defined as a serum creatinine \> 2.5 mg/dL (\> 221 µmol/L) within the last four weeks prior to enrollment.. * Liver failure, defined as three times the upper limit of normal for aminotransferases. * Participation in any other clinical trial. * Unable to return for follow-up visits due to distance from the clinic. * Do not anticipate being a resident of the area for the scheduled duration of the trial.