Myocardial infarction or “heart attack” is an irreversible injury to and eventual death of myocardial tissue that results from ischemia and hypoxia. Myocardial infarction is the leading killer of both men and women in the United States. Most heart attacks are the direct result of occlusion of a coronary blood vessel by a lipid deposit. These lipid deposits may accumulate to the point where they completely block a coronary vessel or, more commonly, accumulated lipid plaques may break off from the vascular endothelium and act as a thrombus that blocks a coronary artery at a narrower point downstream. Prolonged vasospasm might also precipitate a myocardial infarction in certain individuals.