syndrome happens when the heart is not getting enough blood. It is an emergency. It includes
unstable angina and
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
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?
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.
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?
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.
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.
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
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 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
angioplasty (usually with
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
blood pressure at normal levels.
Can acute coronary syndrome be prevented?
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
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.
If you smoke, try to quit. Medicines and counseling 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
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
Other Places To Get Help
American Heart Association (AHA)
7272 Greenville Avenue
Dallas, TX 75231
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.
National Heart, Lung, and Blood Institute
P.O. Box 30105
Bethesda, MD 20824-0105
The U.S. National Heart, Lung, and Blood Institute
(NHLBI) information center offers information and publications about preventing
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
Diseases that affect the blood, such as anemia,
hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.
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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. 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.
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
John M. Miller, MD, FACC - Cardiology, Electrophysiology
How this information was developed to help you make better health decisions.