Acute MI
Alternative names:
heart attack; MI; myocardial infarction
Definition:
A disorder in which damage to an area of heart muscle
occurs because of an inadequate supply of oxygen to that area.
Causes, incidence, and risk factors:
A heart attack occurs when there is clot
formation or spasm in one of the arteries that delivers blood
to the heart (a coronary artery). These and other similar
conditions block the supply of oxygen to an area of the heart,
leading to damage or death of the cells in that area. Most
often, this occurs in a coronary artery that has been narrowed
from changes related to atherosclerosis
(thickening of the artery). The damaged tissue results in
a permanent loss of contraction of this portion of the heart
muscle.
Heart attacks strike approximately 2 out of 1,000 people
per year. It is a major cause of sudden death in adults.
Risk factors for MI include smoking,
hypertension, diabetes
mellitus, high fat
diet, high blood cholesterol
(LDL) levels, obesity,
male gender, age over 65, and heredity. A personal or family
history of coronary artery
disease, cerebrovascular
disease, peripheral vascular
disease, angina (particularly
unstable angina), or
kidney failure requiring
hemodialysis indicates
increased risk for MI. Occasionally, sudden overwhelming stress
can trigger an MI, but this is rare. In older persons, straining
to have a bowel movement can be a risk factor.
Updated Date: 04/01/00
Updated by: David H. Stern, MD Chief Medical
Resident, University of Pennsylvania Hospital, VeriMed Healthcare
Network
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