Atherosclerosis produces fatty plaque deposits that can narrow the arteries that supply oxygen-rich blood to the heart. A heart attack occurs when a blood clot in one of these narrowed arteries suddenly blocks the blood supply, which can result in death or permanent damage to the heart muscle. Each year in the U.S. about 1.2 million people have a heart attack; about half of these heart attacks result in death (survivors often suffer a second or third heart attack). Heart disease is the leading cause of death for both men and women.