Acute Coronary Syndrome

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Acute Coronary Syndrome

Topic Overview

What is acute coronary syndrome?

Acute coronary syndrome happens when the heart is not getting enough blood. It is an emergency. It includes unstable angina and heart attack.

The coronary arteries supply oxygen-rich blood to the heart muscle. If these arteries are narrowed or blocked, the heart does not get enough oxygen. This can cause angina or a heart attack.

  • Unstable angina is chest pain or discomfort from lack of blood flow, but there is no damage to the heart muscle. It often happens when you are at rest. You may have had stable angina before. You knew when to expect your symptoms, such as when you exercised. Stable angina usually goes away when you rest or take your angina medicine. But the symptoms of unstable angina may not go away with rest or medicine. It may get worse or happen at times that it didn't before. Unstable angina is not a heart attack. But it is a warning that a heart attack could happen soon, so it needs to be treated right away.
  • A heart attack means a coronary artery has been blocked and the heart has been damaged. Without blood flow and oxygen, part of the heart starts to die.

Any type of acute coronary syndrome is very serious and needs to be treated right away.

What causes acute coronary syndrome?

Acute coronary syndrome happens because plaque narrows or blocks the arteries that supply blood to the heart. Plaque is made of cholesterol and other things. Over time, plaque can build up in the arteries. This is known as coronary artery disease.

Plaque causes angina by narrowing the arteries. A heart attack happens when a piece of plaque breaks open and a clot forms, blocking an artery.

What are the symptoms?

Call 911 or other emergency services immediately if you have symptoms of acute coronary syndrome. These may include:

  • Chest pain or pressure, or a strange feeling in the chest.
  • Sweating.
  • Shortness of breath.
  • Nausea or vomiting.
  • Pain, pressure, or a strange feeling in the back, neck, jaw, or upper belly, or in one or both shoulders or arms.
  • Light-headedness or sudden weakness.
  • A fast or irregular heartbeat.

After you call 911, the operator may tell you to chew 1 adult-strength or 2 to 4 low-dose ASA. Wait for an ambulance. Do not try to drive yourself.

How is acute coronary syndrome diagnosed?

A doctor will give you a physical examination and ask about your symptoms and past health. He or she also will ask about your family's health. You will have several tests to find out what is causing your chest pain.

An electrocardiogram can show whether you have angina or have had a heart attack. This test measures the electrical signals that control your heart's rhythm. Small pads will be taped to your chest and other areas of your body. They connect to a machine that traces the signals onto paper. The doctor will look for certain changes on the graph to see if your heart is not getting enough blood or you are having a heart attack.

A blood test will look for a rise in cardiac enzymes. The heart releases these substances when it is damaged.

In some cases, you might have a test called a cardiac perfusion scan to see if your heart is getting enough blood. It also can be used to check for areas of damage after a heart attack.

How is it treated?

If you call 911, treatment will start in the ambulance with ASA and other medicines.

In the hospital, the doctor will work right away to return blood flow to your heart. You may get medicines to break up and prevent blood clots. You may get nitroglycerin and other medicines that make your arteries wider. This helps to ease pain and improve blood flow. You also will get oxygen and pain medicine.

Your test results will help your doctor decide about more treatment. If you are having a heart attack, you likely will get medicines to break up clots or have angioplasty (usually with stents) or bypass surgery to improve blood flow to your heart. If you are having unstable angina, you will likely get medicines but you might also have angioplasty with stents.

After you get out of the hospital, you will continue to take medicines such as beta-blockers to help your heart. You will likely take ASA and also may take other medicines that prevent blood clots. You probably also will take medicines to keep your cholesterol and blood pressure at normal levels.

Can acute coronary syndrome be prevented?

Heart disease can lead to acute coronary syndrome. If you do not have heart disease, you may be able to prevent it with a healthy lifestyle:

  • Eat a diet that has lots of fruit, vegetables, whole grains, and lean protein.
  • Stay at a healthy weight.
  • Try to do moderate or vigorous exercise at least 2½ hours a week. One way to do this is to be active 30 minutes a day, at least 5 days a week.
  • If you smoke, try to quit. Medicines and counselling can help you quit for good.
  • Know your numbers. Keep track of your blood pressure and cholesterol levels. A healthy lifestyle can help keep these numbers in a normal range. Many people also take medicine to reach their goals.

People who already have heart disease usually take several medicines to lower the chance of a heart attack. These may include daily low-dose ASA and medicines to lower cholesterol and blood pressure. People who have heart disease also are encouraged to eat a healthy diet, get daily exercise, and not smoke. These steps may prevent a heart attack or stroke.

Other Places To Get Help

Organizations

Canadian Cardiovascular Society
222 Queen Street
Suite 1403
Ottawa, ON  K1P 5V9
Phone: 1-877-569-3407 toll-free
(613) 569-3407
Fax: (613) 569-6574
Web Address: www.ccs.ca
 

The Canadian Cardiovascular Society works to advance the cardiovascular health and care of Canadians through leadership, research, and advocacy.


American Heart Association (AHA)
7272 Greenville Avenue
Dallas, TX  75231
Phone: 1-800-AHA-USA1 (1-800-242-8721)
Web Address: www.heart.org
 

Visit the American Heart Association (AHA) website for information on physical activity, diet, and various heart-related conditions. You can search for information on heart disease and stroke, share information with friends and family, and use tools to help you make heart-healthy goals and plans. Contact the AHA to find your nearest local or state AHA group. The AHA provides brochures and information about support groups and community programs, including Mended Hearts, a nationwide organization whose members visit people with heart problems and provide information and support.


Canadian Association of Cardiac Rehabilitation
1390 Taylor Avenue
Winnipeg, MB  R3M 3V8
Phone: (204) 488-5854
Fax: (204) 928-7873
Web Address: www.cacr.ca
 

The Canadian Association of Cardiac Rehabilitation (CACR) is a professional organization that promotes research in cardiac disease prevention and rehabilitation. The CACR website includes articles on topics related to cardiac disease.


Heart and Stroke Foundation of Canada
222 Queen Street
Suite 1402
Ottawa, ON  K1P 5V9
Phone: (613) 569-4361
Fax: (613) 569-3278
Web Address: www.heartandstroke.ca
 

The Heart and Stroke Foundation of Canada works to improve the health of Canadians by preventing and reducing disability and death from heart disease and stroke through research, health promotion, and advocacy.


U.S. National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD  20824-0105
Phone: (301) 592-8573
Fax: (240) 629-3246
TDD: (240) 629-3255
Email: nhlbiinfo@nhlbi.nih.gov
Web Address: www.nhlbi.nih.gov
 

The U.S. National Heart, Lung, and Blood Institute (NHLBI) information center offers information and publications about preventing and treating:

  • Diseases affecting the heart and circulation, such as heart attacks, high cholesterol, high blood pressure, peripheral artery disease, and heart problems present at birth (congenital heart diseases).
  • Diseases that affect the lungs, such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, sleep apnea, and pneumonia.
  • Diseases that affect the blood, such as anemia, hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.

References

Other Works Consulted

  • Anderson JL, et al. (2007). ACC/AHA 2007 Guidelines for the management of patients with unstable angina/non ST-elevation myocardial infarction: Executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation, 116(7): 803–877.
  • Antman EM, Braunwald E (2008). Acute coronary syndromes section of ST-elevation myocardial infarction: Pathology, pathophysiology, and clinical features. In P Libby et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed., vol. 2, pp. 1210–1211. Philadelphia: Saunders Elsevier.
  • Kim MC, et al. (2008). Definitions of acute coronary syndromes. In V Fuster et al., eds., Hurst's The Heart, 12th ed., pp. 1311–1319. New York: McGraw-Hill Medical.
  • O'Connor RE, et al. (2010). Acute coronary syndromes: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 122(18): S787–S817.
  • Sarkees M, Bavry AA (2009). Acute coronary syndrome (unstable angina and non-ST elevation MI), search date May 2007. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer John M. Miller, MD - Electrophysiology
Last Revised June 6, 2011

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