Definition of myocardial infarction (MI) occurs when myocardial cells die as result of prolonged oxygen deprivation. The most common cause of an MI is a blood clot (thrombosis) forming inside a coronary artery ,or one of its branches.This prevents blood flow to a part of the heart.
Atheroma, a fatty patch or plaque that develops within the inside lining of arteries, is usually responsible for a thrombosis in the coronary arteries usually due to atheroma within the lining of the artery.
In MI (sometimes celled heart attack), a coronary artery or one of its smaller branches in damage to the myocardium. The part of the myocardium supplied by this artery will lose its blood and oxygen supply as a result of the blockage. This part of the muscle is at risk of dying unless the blockage is removed quickly and oxygen supply restored. When this happens, that part of heart muscle is said to be ‘infarcted’.