Health Library

Heart Attack

Definition

A heart attack is when an area of the heart does not get enough blood flow. The area becomes damaged or dies within a short time after blood flow is stopped. If a large or vital area is affected the heart may stop. A heat attack may be:

  • STEMI—A major artery is fully blocked. This is a more serious type of heart attack
  • NSTEMI—Partial block of an artery. The block may also allow periods of some blood flow.
Heart Attack
Heart Attack
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Causes

The coronary arteries bring blood and oxygen to the heart muscle. A heart attack happens when one or more of these arteries is blocked. Blockage may occur because of one or more of the following:

  • Narrowing of the coronary arteries due to one or more of following:
    • Thickening of the artery walls (common aging process)
    • Build-up of fatty plaques inside the arteries
    • Spasm of the coronary arteries
    • Development of a blood clot in the arteries
  • Embolism—a blood clot that travels to the heart from other areas of the body

There are 2 main coronary arteries. They split off into smaller branches that spread out over the heart. A blockage on larger artery will affect more of the heart. It can cause a severe heart attack. Blockages in the smaller arteries will have a smaller effect.

Blockages may only last a short time and then allow some blood flow. Others may last longer and cause more harm.

Risk Factors

The risk of heart attack is greater in males and older adults. The risk of a heart attack is also higher in those with blood vessel disease or damage. Things that may increase risk of blood vessel disease and heart attacks are:

  • Certain health problems, such as:
  • Obesity
  • High blood pressure
  • High blood cholesterol—specifically, high LDL cholesterol, and low HDL cholesterol
  • Diabetes
  • High blood triglycerides
  • Lifestyle habits, such as:
  • Smoking
  • Not getting enough daily activity
  • Cocaine use
  • Use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
  • Stress
  • Family members with heart disease
  • Using testosterone therapy

Symptoms

Symptoms can differ from person to person. Common ones are:

  • Squeezing, heavy chest pain behind breastbone—usually comes on quickly especially with:
    • Exercise or exertion
    • Emotional stress
    • Cold weather
    • A large meal
  • Pain in the left shoulder, left arm, or jaw
  • Shortness of breath
  • Sweating, clammy skin
  • Nausea
  • Weakness
  • Loss of consciousness
  • Anxiety, or a sense of doom or panic without apparent reason

Unusual symptoms of heart attack—more common in women:

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

Call for emergency services right away if you think you may be having a heart attack. Early care can stop further damage.

Diagnosis

A heart attack is an emergency. Tests to confirm a heart attack and look for changes in the heart include:

  • ECG—shows the electrical activity of the heart. It can show if a heart attack has happened or may be happening. ECG can show if the heart attack is STEMI or NSTEMI.
  • Blood tests—can show markers in the blood. These markers appear when a heart attack occurs. They can also show how much damage was done to the heart muscle.
  • Echocardiogram—shows the size, shape, and motion of the heart.
  • Coronary angiography—Can help find blockages or damage to the arteries.

Other tests will be based on a person's specific needs. They may include:

  • Stress test—records the heart's electrical activity under physical stress. This may be done days or weeks after the heart attack.
  • Electron-beam computed tomography (EBCT)—takes pictures of the heart, coronary arteries, and surrounding area.

Treatment

The first goal of treatment is to improve blood flow and get oxygen to the heart as fast as possible. Treatment includes:

  • Aspirin and other antiplatelet agents—to break up clots in the blood and improve blood flow. It works best when given within the first 6 hours after symptoms appear.
  • Oxygen therapy—to increase oxygen to the heart.
  • Nitrate medicines—to quickly open blood vessels and improve blood flow to heart muscle.
  • Medicine to ease pain
  • Beta-blockers and/or angiotensin-converting enzyme (ACE) inhibitors—to decrease the workload on the heart.
  • Anti-anxiety medicine

Surgery

Surgery may be needed for clots that do not respond to medicine. Some blockages may also be caused by a buildup of plaque in blood vessels. Surgery can help to improve blood flow. Surgical options include:

  • Balloon angioplasty—A wire is passed through blood vessels to the heart. A balloon is inflated to open the blocked artery. A mesh device called a stent may also be placed. It will help prop the area open.
  • Coronary artery bypass grafting (CABG)—Part of a blood vessel from another area of the body will be taken. It will be attached above and below the blocked area. This will help create blood flow around the blockage.

Recovery

Cardiac rehabilitation can help after a heart attack. It will teach healthy habits to decrease the risk of another heart attack. The program will also monitor the heart as physical activity is increased. Severe heart attacks can also make the heart weaker. Rehabilitation can help to adjust to changes.

A heart attack can be a major life event. It is common for people to have depression after a heart attack. Therapy and medicine can help to manage these challenges.

Prevention

Healthy heart habits include:

Small daily doses of aspirin may help some people decrease their risk. This should only be done with a doctor’s approval. Aspirin can have side effects like bleeding in the stomach. Aspirin may also cause problems with other medicine.

Resources

American Heart Association
http://www.heart.org

National Stroke Association
http://www.stroke.org

Canadian Resources

Heart and Stroke Foundation of Canada
http://www.heartandstroke.ca

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

References

Davidson KW, Barry MJ, et al. Aspirin use to prevent cardiovascular disease: US Preventive Services Task Force Recommendation Statement. JAMA. 2022;327(16):1577-1584.

ST-elevation myocardial infarction (STEMI). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/st-elevation-myocardial-infarction-stemi.

What is a heart attack? American Heart Association website. Available at: https://www.heart.org/en/health-topics/heart-attack/about-heart-attacks.

What is a heart attack? National Heart Lung and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/heart-attack.

7/17/2017 DynaMed Systematic Literature Surveillance https://www.dynamed.com/condition/acute-coronary-syndromes: Bally M, Dendukuri N, et al. Risk of acute myocardial infarction with NSAIDs in real world use: bayesian meta-analysis of individual patient data. BMJ. 2017;357:j1909.