Acute coronary syndrome is a term used to describe a range of conditions associated with sudden, reduced blood flow to the heart.

One condition under the umbrella of acute coronary syndrome is myocardial infarction (heart attack) — when cell death results in damaged or destroyed heart tissue. Even when acute coronary syndrome causes no cell death, the reduced blood flow alters heart function and indicates a high risk of heart attack.

Acute coronary syndrome often causes severe chest pain or discomfort. It is a medical emergency that requires prompt diagnosis and care. Treatment goals include improving blood flow, treating complications and preventing future problems.


The signs and symptoms of acute coronary syndrome, which usually begin abruptly, include the following:

  • Chest pain (angina) or discomfort, often described as aching, pressure, tightness or burning
  • Pain radiating from the chest to the shoulders, arms, upper abdomen, back, neck or jaw
  • Nausea or vomiting
  • Indigestion
  • Shortness of breath (dyspnea)
  • Sudden, heavy sweating (diaphoresis)
  • Lightheadedness, dizziness or fainting
  • Unusual or unexplained fatigue
  • Feeling restless or apprehensive

While chest pain or discomfort is the most common symptom associated with acute coronary syndrome, signs and symptoms may vary significantly depending on your age, sex and other medical conditions. People who are more likely to have signs and symptoms without chest pain or discomfort are women, older adults and people with diabetes.

When to see a doctor

Acute coronary syndrome is a medical emergency, and chest pain or discomfort can indicate any number of serious, life-threatening conditions. Call 911 or get immediate emergency services to get a prompt diagnosis and appropriate care. Do not drive yourself to an emergency department.


Acute coronary syndrome usually results from the buildup of fatty deposits (plaques) in and on the walls of coronary arteries, the blood vessels delivering oxygen and nutrients to heart muscles.

When a plaque deposit ruptures or splits, a blood clot forms. This clot obstructs the flow of blood to heart muscles.

When the supply of oxygen to cells is too low, cells of the heart muscles can die. The death of cells — resulting in damage to muscle tissues — is a heart attack (myocardial infarction).

Even when there is no cell death, an inadequate supply of oxygen still results in heart muscles that don't work correctly or efficiently. This dysfunction may be temporary or permanent. When acute coronary syndrome doesn't result in cell death, it is called unstable angina.

Risk factors

The risk factors for acute coronary syndrome are the same as those for other types of heart disease. Acute coronary syndrome risk factors include:

  • Older age (older than 45 for men and older than 55 for women)
  • High blood pressure
  • High blood cholesterol
  • Cigarette smoking
  • Lack of physical activity
  • Unhealthy diet
  • Obesity or overweight
  • Diabetes
  • Family history of chest pain, heart disease or stroke
  • For women, a history of high blood pressure, preeclampsia or diabetes during pregnancy
Aug. 02, 2017
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