Heart Disease Health Center

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.
• 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 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.