Acute Coronary Syndrome

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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 happens when blood flow to the heart is suddenly slowed by narrowed coronary arteries. Or small blood clots form in the coronary arteries and slow blood flow. Typically, 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 blood flow has slowed or stopped in the arteries that supply blood to the heart. Acute coronary syndrome is typically caused by coronary artery disease. Coronary artery disease, also called heart disease, is caused by atherosclerosis, or hardening of the arteries.

Atherosclerosis causes a substance called plaque to build up in the coronary arteries. Plaque causes angina by narrowing the arteries. The narrowing limits blood flow to the heart muscle. A heart attack happens when blood flow is completely blocked.

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.
  • Lightheadedness 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 aspirin. Wait for an ambulance. Do not try to drive yourself.

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 symptoms.

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 or patches 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 if 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 medicines to break up and prevent blood clots. You may get nitroglycerin and other medicines that make your arteries wider. This helps improve blood flow and relieve symptoms, such as chest pain or pressure. You also may get pain medicine and oxygen.

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 that lower your risk of a heart attack. Medicine may include beta-blockers, aspirin or other medicines to prevent blood clots, blood pressure medicine, and statins for cholesterol.

Can acute coronary syndrome be prevented?

A heart-healthy lifestyle can help prevent heart disease, which can lead to acute coronary syndrome. If you already have heart disease, a heart-healthy lifestyle along with medicine can help prevent a heart attack.

  • Eat a heart-healthy diet that has lots of fruit, vegetables, whole grains, and lean protein.
  • Stay at a healthy weight. Lose weight if you need to.
  • Be active. Your doctor can suggest a safe level of exercise for you.
  • Don't smoke.
  • Manage other health problems, including diabetes, high blood pressure, and high cholesterol.
  • Lower your stress level. Stress can damage your heart.
  • Take a daily aspirin if your doctor advises it.

Other Places To Get Help

Organizations

National Heart, Lung, and Blood Institute (NHLBI) (U.S.)
www.nhlbi.nih.gov
American Heart Association (AHA)
www.heart.org
American College of Cardiology: CardioSmart
www.cardiosmart.org

References

Other Works Consulted

  • Antman EM (2012). ST-elevation myocardial infarction: Pathology, pathophysiology, and clinical features. In RO Bonow et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed., vol. 2, pp. 1087–1110. Philadelphia: Saunders.
  • Jneid H, et al. (2012). 2012 ACCF/AHA Focused update of the guideline for the management of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation, 126(7): 875–910.
  • Kim MC, et al. (2011). Definitions of acute coronary syndromes. In V Fuster et al., eds., Hurst's the Heart, 13th ed., vol. 2, pp. 1287–1295. New York: McGraw-Hill.
  • 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 ML, Bavry AA (2010). Non ST-elevation acute coronary syndrome, search date December 2009. BMJ Clinical Evidence. Available online: http://www.clinicalevidence.com.
  • Thygesen K, et al. (2012). Third universal definition of myocardial infarction. Circulation, 126(16): 2020–2035. Also available online: http://circ.ahajournals.org/content/126/16/2020.

Credits

ByHealthwise Staff
Primary Medical ReviewerRakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical ReviewerStephen Fort, MD, MRCP, FRCPC - Interventional Cardiology

Current as ofAugust 13, 2014