What is Heart Attack?

A heart attack occurs when blood flow to a section of heart muscle becomes blocked. If the flow of blood isn't restored quickly, the section of heart muscle becomes damaged from lack of oxygen and begins to die.

Figure A is an overview of a heart and coronary artery showing damage (dead heart muscle) caused by a heart attack.
Figure B is a cross-section of the coronary artery with plaque buildup and a blood clot.

Heart attack is a leading killer of both men and women in the United States. But fortunately, today there are excellent treatments for heart attack that can save lives and prevent disabilities. Treatment is most effective when started within 1 hour of the beginning of symptoms. If you think you or someone you're with is having a heart attack, call 9-1-1 right away.

Heart attacks occur most often as a result of a condition called Coronary Artery Disease (CAD). In CAD, a fatty material called plaque (plak) builds up over many years on the inside walls of the coronary arteries (the arteries that supply blood and oxygen to your heart). Eventually, an area of plaque can rupture, causing a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block the flow of oxygen-rich blood to the part of the heart muscle fed by the artery.

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