Heart Attack

(Acute Myocardial Infarction [AMI]; Myocardial Infarction [MI]; ST-Segment-Elevation MI [STEMI]; Transmural Myocardial infarction)



A heart attack occurs when blood flow to the heart muscle is interrupted. Oxygen cannot get to the heart muscle, causing tissue damage or tissue death.

Heart Attack

Copyright © Nucleus Medical Media, Inc.



A heart attack may be caused by:

  • Thickening of the walls of the arteries feeding the heart muscle (coronary arteries)
  • Build up of fatty plaques in the coronary arteries
  • Narrowing of the coronary arteries
  • Spasm of the coronary arteries
  • Development of a blood clot in the coronary arteries
  • Embolism that affects the coronary arteries

Risk Factors

Risk Factors

The risk of heart attack is greater in males and older adults.

Factors that may increase your chance of developing a heart attack include:



Symptoms include:

  • Squeezing, heavy chest pain behind breastbone, especially with:

    • Exercise or exertion
    • Emotional stress
    • Cold weather
    • A large meal
    • Usually comes on quickly
  • Pain in the left shoulder, left arm, or jaw
  • Shortness of breath
  • Sweating, clammy skin
  • Nausea
  • Weakness
  • Loss of consciousness
  • Anxiety, especially feeling a sense of doom or panic without apparent reason

Unusual symptoms of heart attack—may occur more frequently in women:

  • Stomach pain
  • Back and shoulder pain
  • Confusion
  • Fainting

If you think you are having a heart attack, call for emergency medical services right away.



Your bodily fluids may be tested. This can be done with:

  • Blood tests—To look for certain enzymes found in the blood within hours or days after a heart attack
  • Urine tests—To look for certain substances found in the urine within hours or days after a heart attack

Your heart function may be tested. This can be done with:

  • Electrocardiogram (EKG) —to look for evidence of blockage or damage
  • Echocardiogram —to examine the size, shape, function, and motion of the heart
  • Stress test —Records the heart’s electrical activity under increased physical stress, usually done days or weeks after the heart attack

Images may be taken. This can be done with:

  • Nuclear scanning—show areas of the heart muscle where there is diminished blood flow
  • Electron-beam computed tomography (EBCT)—to make detailed pictures of the heart, coronary arteries, and surrounding structures
  • Coronary angiography —To look for narrowing or blockage in the coronary arteries



Treatment includes:

  • Aspirin
  • Oxygen
  • Pain-relieving medication
  • Nitrate medications
  • Other antiplatelet agents
  • Beta-blockers and/or angiotensin-converting enzyme (ACE) inhibitor medications
  • Anti-anxiety medication
  • Cholesterol-lowering medications such as statin drugs

Within the first six hours after a heart attack, you may be given medications to break up blood clots in the coronary arteries.


If you have severe blockages you may need surgery right away or after recovery, such as:

Physical or Rehabilitative Therapy

During recovery, you may need physical or rehabilitative therapy to help you regain your strength.

Treatment for Depression

You may feel depressed after having a heart attack. Therapy and medication can help relieve depression.



Preventing or treating coronary artery disease may help prevent a heart attack.

  • Maintain a healthy weight.
  • Begin a safe exercise program. Follow your doctor’s advice.
  • If you smoke, talk to your doctor about ways to quit.
  • Eat a healthy diet. Your diet should be low in saturated fat and rich in whole grains, fruits, and vegetables.
  • Properly treat long-term conditions, like high blood pressure, diabetes, and high cholesterol.
  • Manage stress.
  • Ask your doctor about taking a small, daily dose of aspirin.

    • Although most people are able to tolerate such a low dose of aspirin, even this small amount can rarely lead to serious bleeding, particularly from the gastrointestinal (GI) tract.
    • Aspirin may not work as well when combined with other pain medications.



College of Family Physicians of Canada http://www.cfpc.ca

Heart and Stroke Foundation http://www.heartandstroke.com


About heart attacks. American Heart Association website. Available at:
Updated September 2, 2014. Accessed September 29, 2014.

ST-elevation myocardial infarction (STEMI). EBSCO DynaMed website. Available at:
Updated August 27, 2014. Accessed September 29, 2014.

What is a heart attack? National Heart Lung and Blood Institute website. Available at:
Updated December 13, 2013. Accessed September 29, 2014.

7/6/2009 DynaMed’s Systematic Literature Surveillance
Antithrombotic Trialists’ (ATT) Collaboration, Baigent C, Blackwell L, et al. Aspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials. Lancet. 2009;373:1849-1860.

2/3/2014 DynaMed’s Systematic Literature Surveillance
Finkle W, Greenland S, et al. Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men. PLoS One. 2014;9(1).

Last reviewed August 2014 by Michael J. Fucci, DO
Last Updated: 9/29/2014

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