Acute Coronary Syndrome

(Also called: Angina, stable angina, unstable angina, heart attack, STEMI, non-STEMI)

Any heart condition that leads to a sudden slowing or blockage of blood supply to the heart is referred to as an acute coronary syndrome (ACS). If you have chest pain (angina), or pressure in your chest typical of a heart attack, then you are considered as having ACS until proven otherwise. ACS is a serious event which requires urgent attention and treatment. 

What Is Acute Coronary Syndrome

Acute coronary syndrome is a general term for any situation where the blood supply to any part of your heart is suddenly reduced or blocked. It is an urgent situation that requires immediate treatment. Once a diagnosis is made, you will receive immediate treatment which may include procedures such as cardiac catheterization, angioplasty, or even cardiac surgery. Once your condition is stabilized, further treatments include medications, lifestyle modifications, and follow-up care.

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The most common cause of ACS is coronary artery disease or narrowing of the coronary arteries. These are the vessels which feed blood to the heart muscle. This narrowing is usually caused by the buildup of cholesterol plaque in artery walls, leading to atherosclerosis or hardening of the arteries.

In some cases, ACS can happen when plaque in the artery cracks open suddenly. A blood clot forms over the cracked plaque and creates a narrowing inside the artery which partially or completely blocks blood flow. The sudden reduction of blood supply to the heart muscle cells causes them to die.

There are various conditions that fall under the ACS umbrella.

Unstable Angina

This occurs when plaque in the artery cracks open suddenly. A blood clot forms over the cracked plaque and creates a sudden narrowing inside the artery. When this happens, chest pain or angina may occur more frequently, with less exercise, or last longer than usual. This change in the pattern of angina is called unstable angina and puts you at increased risk for heart attack.

Heart Attack

If the heart is starving for blood and not getting enough oxygen for more than 20 minutes, then a part of the heart muscle dies causing some permanent damage. Heart attacks (also called myocardial infarction) are confirmed with blood tests as well as a test that shows the electrical activity of the heart called an electrocardiogram (ECG).

Some heart attacks involve only a small area of the heart and can be managed with standard medical treatment in hospital. But if the coronary artery in question becomes completely blocked by clots, blood flow stops entirely and the full thickness of heart muscle fed by that artery is damaged. This causes a characteristic change on the ECG called an ST-segment elevation myocardial infarction (STEMI) and requires immediate treatment. 


Based on your symptoms, you will likely have some blood tests, a physical examination, and an electrocardiogram.

If the results indicate that blood flow to the heart has been blocked, you will be treated immediately.


ACS may occur at rest or during exertion. Symptoms can include any of the following:

  • Chest pain, often described as a tightness or heaviness
  • Pain in the upper abdomen
  • Pain in the back, neck, jaw, or arm
  • Shortness of breath
  • Sweating
  • Nausea
  • Loss of consciousness

Unlike men, for some women, chest pain may not be the first sign of heart trouble. These women report less common symptoms, such as unusual tiredness, trouble sleeping, indigestion, and anxiety up to a month before the heart attack. Women with diabetes often have less common symptoms.

If you think you may be having a heart attack, call 911.

Symptoms of Acute Coronary Syndrome in Men: Pain in the back, neck, and jaw; chest pain, heaviness, or tightness; shortness of breath; loss of consciousness; sweating; pain in the shoulder or arm; indigestion; nausea; stomach pain

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Symptoms of Acute Coronary Syndrome in Women: Pain in the shoulder or arm, Shortness of breath, Chest pain, discomfort or pressure, Back pain, Tiredness, Trouble sleeping, Anxiety, Sweating, Indigestion

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Risk Factors for Cardiovascular Disease

Learn about risk factors for heart disease and strategies for managing them to improve your overall heart health.