A heart attack occurs when a blood vessel in the heart becomes blocked and cuts off the blood supply to the heart muscle, causing that area of the heart to die. The blood vessels that supply blood to the heart are the coronary arteries.
Myocardial infarction is the medical term for a heart attack.
A heart attack can occur when you are at rest or during exertion. When blood clots in the heart or coronary arteries block the flow of blood to the heart muscle, the muscle tissue is injured. If the blockage persists for many minutes or hours, the tissues will die. If a very small portion of heart muscle is affected, heart function after recovery may be normal. If a moderate-sized section has been damaged, the heart may never pump as efficiently again.