Cardiac Resynchronization Therapy (CRT) is a widely accepted treatment that has led to improved clinical outcomes for patients with refractory congestive heart failure (CHF), systolic dysfunction, and wide QRS duration. However, it requires implantation of an expensive device ($30,000) and about 1/3 of patients do not have clinical improvement. Inadequate amounts of LV dyssynchrony or suboptimal lead placement may limit clinical response. Dual-Source computed tomography (DSCT) allows for subtle detection during myocardial contraction for assessing LV dyssynchrony, and can also assess coronary venous anatomy and scar burden. Thus DSCT may be the ideal noninvasive modality to predict response to CRT.