A heart attack, also known as a myocardial infarction, usually occurs when a blood clot forms inside a coronary artery at the site of an atherosclerotic plaque. The blood clot severely limits or completely cuts off blood flow to part of the heart. In a small percentage of cases, blood flow is cut off when the muscles in the artery wall contract suddenly, constricting the artery. This constriction, called vasospasm, can occur in an artery that is only slightly narrowed by atherosclerosis or even in a healthy artery. Regardless of the cause of a heart attack, the oxygen deprivation is so severe and prolonged that heart muscle cells begin to die for lack of oxygen. About 1.1 million people in the United States have a heart attack every year; the heart attacks prove fatal for about 40 percent of these people (Microsoft Encarta, 2004).
ETIOLOGY
The most common cause of acute myocardial infarction (AMI) is complete or nearly complete occlusion of a coronary artery usually......
Join Now or Login to view the rest of this paper.
Approximate Word Count: 2451
Approximate Pages: 10 (260 words per double-spaced page) |