Acute coronary syndrome


Acute coronary syndrome is a term for a group of conditions that suddenly stop or severely reduce blood from flowing to the heart. When blood cannot flow to the heart, the heart muscle can become damaged. Heart attack and unstable angina are both acute coronary syndromes (ACS).


A fatty substance called plaque can build up in the arteries that bring oxygen-rich blood to your heart. Plaque is made up of cholesterol, fat, cells, and other substances.

Plaque can block blood flow in 2 ways:

Many risk factors for heart disease may lead to an ACS.


The most common symptom of ACS is chest pain. The chest pain may come on quickly, come and go, or get worse with rest. Other symptoms can include:

Women and older people often experience these other symptoms, although chest pain is common for them as well.

Exams and Tests

Your health care provider will do an exam, listen to your chest with a stethoscope, and ask about your medical history.

Tests for ACS include:

Coronary angiography may be done right away or when you are more stable. This test:

Other tests to look at your heart that may be done while you are in the hospital include:


Your provider may use medicines, surgery, or other procedures to treat your symptoms and restore blood flow to your heart. Your treatment depends on your condition and the amount of blockage in your arteries. Your treatment may include:

Outlook (Prognosis)

How well you do after an ACS depends on:

In general, the quicker your artery gets unblocked, the less damage you will have to your heart. People tend to do best when the blocked artery is opened within a few hours from the time symptoms start.

Possible Complications

In some cases, ACS can lead to other health problems including:

When to Contact a Medical Professional

An ACS is a medical emergency. If you have symptoms, call 911 or your local emergency number quickly.



There is a lot you can do to help prevent ACS.

Review Date: 5/16/2018
Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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