A new MRI technique to examine the heart was recently developed. In this study, researchers will use this new technique to evaluate the heart in people who have recently had a heart attack to determine whether a specific pattern of heart muscle damage is related to sudden cardiac death. This fatal condition, also known as cardiac arrest, occurs when the heart abruptly stops pumping blood to the body, resulting in loss of consciousness, absence of pulse, and a stop in breathing. The most common cause of sudden cardiac death is a heart attack.