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What Is a Heart Attack?

a man grabbing his chest with his hands.


A heart attack happens when the flow of oxygen-rich blood in one or more of the coronary arteries, which supply the heart muscle, suddenly becomes blocked, and a section of heart muscle can’t get enough oxygen. The blockage is usually caused when a plaque ruptures. If blood flow isn’t restored quickly, either by a medicine that dissolves the blockage or a catheter placed within the artery that physically opens the blockage, the section of heart muscle begins to die.

Learn more about The Heart Truth®, a national heart disease awareness campaign for women from the National Heart, Lung, and Blood Institute.

Heart attacks are a leading killer of both men and women. Each year, more than 1 million people in the United States have a heart attack, and about half of them die. Half of those who die do so within 1 hour of the start of symptoms and before reaching the hospital.

A heart attack is an emergency. Learn the warning signs of a heart attack. The signs can include:

  • Crushing chest pain or pressure and/or discomfort or pain elsewhere in the upper body, neck, or arms
  • Nausea
  • A cold sweat
  • Fainting or lightheadedness
  • Shortness of breath

If you or someone you know might be having a heart attack, call 9-1-1 right away. Also call 9-1-1 if you are taking prescription drugs for angina (chest pain) and the pain doesn’t go away as usual after you take the medication. You need to take an ambulance to the hospital as soon as possible. Do not try to drive yourself, and do not have someone else drive you unless there is no ambulance service where you live. While waiting for the ambulance, the patient can be given one regular strength or baby aspirin and told to chew and swallow it if possible.

The sooner you get to a hospital, the more emergency medical professionals can do to stop any heart damage and prevent deadly heart rhythm problems, heart failure, and death. If blood flow in the blocked artery can be restored quickly, permanent heart damage may be prevented. Yet, many people do not seek medical care for 2 hours or more after symptoms start.

The good news is that excellent treatments are available for heart attacks. These treatments—which work best when given right after symptoms occur—can save lives and prevent disabilities.

To learn more about heart attacks, visit the National Heart, Lung, and Blood Institute.

For More Information About Heart Attacks

American Heart Association

National Heart, Lung, and Blood Institute

National Cancer Institute

This content is provided by the NIH National Institute on Aging (NIA). NIA scientists and other experts review this content to ensure it is accurate and up to date.

An official website of the National Institutes of Health