Acute Coronary Syndrome

Topic Overview

What is acute coronary syndrome?

Acute coronary syndrome is chest pain and other symptoms that happen because the heart does not get enough blood. 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 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 chest pain, such as when you exercised. The pain of stable angina usually goes away when you rest or take your angina medicine. But the pain 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?

The symptoms of acute coronary syndrome include:

  • Chest pain, which can feel different for everyone. The pain may feel like pressure or squeezing. Your chest may feel tight or heavy. Or you may feel a dull ache or burning. Some people have no chest pain but have other symptoms.
  • Pain in the jaw, neck, arms, back, or belly. Some people have pain in these areas instead of in the chest, or along with pain in the chest.
  • Nausea.
  • Vomiting.
  • Sweating.
  • Feeling dizzy or lightheaded.

If you have any of these symptoms, call 911 or your local emergency services. After you call, chew 1 adult-strength (325 mg) or 2 to 4 low-dose (81 mg) aspirin if you are not allergic to aspirin and if there is no other reason that you can't take aspirin.

How is acute coronary syndrome diagnosed?

A doctor will give you a physical exam 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 aspirin and other medicines.

In the hospital, the doctor will work right away to return blood flow to your heart. You may get heparin and other 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 aspirin 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 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.1
  • Do not smoke, and avoid secondhand smoke. If you do smoke, talk to your doctor about ways to quit.
  • 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 aspirin 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.

References

Citations

  1. U.S. Department of Health and Human Services (2008). 2008 Physical Activity Guidelines for Americans (ODPHP Publication No. U0036). Washington, DC: U.S. Government Printing Office. Available online: http://www.health.gov/paguidelines/pdf/paguide.pdf.

Other Works Consulted

  • 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.

Credits

Author Robin Parks, MS
Editor Kathleen M. Ariss, MS
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer John A. McPherson, MD, FACC - Cardiology
Last Updated June 3, 2009

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