A heart attack, or myocardial infarction (MI), is permanent damage to the heart muscle. "Myo" means muscle, "cardial" refers to the heart, and "infarction" means death of tissue due to lack of blood supply.
A closer look inside your coronary arteries
Your heart muscle needs to receive a good supply of blood at all times to function properly. Your heart muscle gets the blood it needs to do its job from the coronary arteries.
What is coronary artery disease?
Coronary artery disease is the narrowing or blockage of the coronary arteries caused by atherosclerosis. Atherosclerosis (sometimes called "hardening" or "clogging" of the arteries) is the buildup of cholesterol and fatty deposits (called plaque) on the inner walls of the arteries that restricts blood flow to the heart.
Without adequate blood, the heart becomes starved of oxygen and the vital nutrients it needs to work properly. This can cause chest pain called angina. When one or more of the coronary arteries are completely blocked, a heart attack (injury to the heart muscle) may occur.
What happens during a heart attack?
A network of blood vessels known as coronary arteries surround the heart muscle and supply it with blood that is rich in oxygen. The heart muscle needs this oxygen to function.
A heart attack occurs when a coronary artery becomes suddenly blocked, stopping the flow of blood to the heart muscle and damaging it. All or part of the heart muscle becomes cut off from its oxygen supply. Left without oxygen, the heart muscle is injured.