Heart attacks result from blood vessel disease in the heart.
A heart attack also can be caused by a blood clot lodged in a coronary artery. Such an event is sometimes called a coronary thrombosis or coro- nary occlusion. If the blood supply is cut off drastically or for a long time, muscle cells suffer irreversible injury and die. Disability or death can result, depending on how much heart muscle is damaged. Sometimes a coronary artery temporarily contracts or goes into spasm.