Identifying & optimizing strategies to reduce the burden of heart failure is vital. Despite advances in pharmacotherapy, patients with heart failure are at high risk for death & hospitalization. Cardiac resynchronization therapy (CRT) synchronizes ventricular mechanical activity, improves cardiac output & reduces HF symptoms. However, ~50% of patients do not clearly respond to CRT. Sub-optimal placement of the LV pacing lead appears to be an important reason for non-response.