Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart is starved of oxygen and heart cells die.
The medical term for this is myocardial infarction.
A substance called plaque can build up in the walls of your coronary arteries. This plaque is made up of cholesterol and other cells.
A heart attack may occur when:
A tear in the plaque occurs. This triggers blood platelets and other substances to form a blood a clot at the site that blocks blood from flowing to the heart. This is the most common cause of heart attack.
A slow buildup of plaque may narrow one of the coronary arteries so that it is almost blocked.
The cause of heart attack is not always known.
Heart attack may occur:
When you are resting or asleep
After a sudden increase in physical activity
When you are active outside in cold weather
After sudden, severe emotional or physical stress, including an illness
The pain most often lasts longer than 20 minutes. Rest and a medicine to relax the blood vessels (called nitroglycerin) may not completely relieve the pain of a heart attack. Symptoms may also go away and come back.
Some people (the elderly, people with diabetes, and women) may have little or no chest pain. Or, they may have unusual symptoms such as shortness of breath, fatigue, and weakness. A "silent heart attack" is a heart attack with no symptoms.
Exams and Tests
A doctor, nurse or other health care provider will perform a physical exam and listen to your chest using a stethoscope.
The health professional may hear abnormal sounds in your lungs (called crackles), a heart murmur, or other abnormal sounds.
You may have a fast or uneven pulse.
Your blood pressure may be normal, high, or low.
You will have an electrocardiogram (ECG) to look for heart damage. A blood test can show if you have heart tissue damage. This test can confirm that you are having a heart attack.
You will likely need to take medicines, some for the rest of your life. Always talk to your health care provider before stopping or changing how you take any medicines. Stopping certain medications can be deadly.
While under the care of your health care team, you will learn:
How to take medicines to treat your heart problem and prevent more heart attacks
After a heart attack, you have a higher chance of having another heart attack.
How well you do after a heart attack depends on several factors such as:
The damage to your heart muscle and heart valves
Where that damage is located
Your medical care after the heart attack
If your heart can no longer pump blood out to your body as well as it used to, you may develop heart failure. Abnormal heart rhythms can occur, and they can be life-threatening.
Most people can slowly go back to normal activities after a heart attack. This includes sexual activity. Talk to your health care provider about how much activity is good for you.
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Cannon CP, Braunwald E. Unstable angina and non-ST elevation myocardial infarction. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsever; 2011:chap 56.
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Wright RS, Anderson JL, Adams CD, et al. 2011 ACCF/AHA Focused Update of the Guidelines for the Management of Patients with Unstable Angina/Non-ST-Elevation Myocardial Infarction (Updating the 2007 Guideline). A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the American College of Emergency Physicians, Society for Cardiovascular Angiograpy and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2011;57:1920-1959.
Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.