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Heart attack    See images

Overview | Symptoms | Treatment | Prevention

Alternative names:

Myocardial infarction; MI; Acute MI

Definition:

A heart attack is when an area of heart muscle dies or is damaged because of an inadequate supply of oxygen to that area.

Causes and Risks

Heart attacks are often caused by a clot that blocks one of the coronary arteries (the blood vessels that bring blood and oxygen to heart muscle). The clot prevents blood and oxygen from reaching that area of the heart, leading to the death of heart cells in that area. Usually, this occurs in a coronary artery that has been narrowed from changes related to atherosclerosis. The damaged heart tissue permanently loses its ability to contract.

The risk factors for heart attack include:

A personal or family history of coronary artery disease, cerebrovascular disease, peripheral vascular disease, angina (particularly unstable angina), or kidney failure requiring hemodialysis also increase the risk for heart attack.

Occasionally, sudden overwhelming stress can trigger a heart attack, but this is rare. In older persons, straining to have a bowel movement can be a risk factor.

Newer risk factors for coronary artery disease have been identified over the past several years, including elevated homocysteine levels, elevated c-reactive protein, and apo-a. Homocysteine levels can be treated with folic acid supplements in the diet. Studies are still ongoing about the practical value of these new markers.

Chest pain is a major symptom of heart attack, but in many cases the pain may be subtle or even completely absent, especially in the elderly and diabetics. Other symptoms such as weakness, shortness of breath, nausea, or vomiting may predominate.

Heart attack accounts for 1 out of every 5 deaths. It is a major cause of sudden death in adults.

Ency. home > Disease > H > Heart attack

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