U.S. Food 
and Drug Administration

How a Heart Attack Happens

Heart disease most often occurs when cholesterol accumulates and forms "plaque" in a coronary artery. With blood flow impeded, the heart becomes starved for oxygen, causing chest pain (angina). If a blood clot forms and completely obstructs the artery, a heart attack (myocardial infarction) can occur.

(Source: American Heart Association)

illustration of clot in heart blocking blood flow

FDA Consumer magazine (January-February 1999)

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