A heart attack (myocardial infarct) is caused by a blockage of one of the coronary arteries that sit on the outside of the heart.
Usually there is a slow build of cholesterol over time (atherosclerotic plaque) within the artery that leads to a narrowing (stenosis). If a blood clots blocks this narrowing acutely a myocardial infarction occurs.
If the artery is not opened up quickly with a stent, the heart muscle is permanently damaged leaving an area of scar within the heart.
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