Some patients who are treated with a cardiac resynchronization therapy or “CRT” device, commonly known as a biventricular pacemaker, can derive significant benefit from the optimization of timing of their devices. The optimization process normally requires an echocardiogram, but the results can be imprecise, and some patients who receive this treatment do not go on to have improved outcomes. This study investigates the role of using an electrocardiogram for CRT optimization in place of the echocardiogram. The hypothesis is that this method can improve the precision and effectiveness of the optimization process. Additionally, an electrocardiogram is a much simpler procedure than an echocardiogram, which may lead to increased convenience for patients, and reduced health care costs, along with potentially improved outcomes. This study is supported by grants from the Michael Wolk Heart Foundation and the New York Cardiac Center. The principal investigator is Jim W. Cheung, MD. The study is currently open to enrollment: see studies open to enrollment.