A heart attack is an event that occurs when part of the heart muscle does not get enough blood and oxygen. This part of the heart starts to die.

A heart attack most often happens because blood flow through one or more of the coronary arteries is blocked. This blockage is usually caused by a blood clot that forms when plaque in the artery breaks open.

Quick treatment that restores blood flow to the heart can help save lives.

The medical name for a heart attack is myocardial infarction, or MI. It may also be called acute coronary syndrome.