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 symptoms may mean that you are having a heart attack.
• 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 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. 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 aspirin. 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 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 oxygen and pain medicine.

Your test results will help your doctor decide about more treatment. You may have angioplasty or bypass surgery to improve blood flow to your heart.

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 that prevent blood clots, blood pressure medicine, and cholesterol medicine.

Healthy lifestyle changes also lower your chance of having a heart attack. Quitting smoking, eating heart-healthy foods, getting regular exercise, and staying at a healthy weight are important steps you can take.

If your doctor has not set you up with a cardiac rehab program, talk to him or her about whether that is right for you. In cardiac rehab, you will get education and support that help you make new, healthy habits, such as eating healthy food and getting more exercise.

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 get at least 2½ hours of moderate to vigorous exercise 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 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.