The definition of heart attack (also known as myocardial infarction) is the death of heart muscle from the sudden obstruction of a coronary artery by a blood clot.
Coronary arteries are blood vessels that supply the heart muscle with blood and oxygen. Obstruction of the coronary arteries seize or remove oxygen from the blood and heart muscle, causing injury to the heart muscle. There are wounds of the heart muscle causes chest pain and feeling (sensation) chest pressure.
If blood flow is not restored back to the heart muscle within 20 to 40 minutes, death of heart muscle that can not be restored again, will begin to happen. Muscle continues to die for six to eight hours, at which time the heart attack usually is "fully". Heart muscle that dies eventually replaced by scar tissue.
Approximately one million Americans suffer heart attacks each year. Four hundred thousand of them died, as a result of a heart attack.
