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CAD: Acute Coronary Syndrome

Heart Attack: An Acute Coronary Syndrome

Acute Coronary Syndrome is a name given to three types of coronary artery disease that are associated with sudden rupture of plaque inside the coronary artery:

  • Unstable angina
  • Non-ST segment elevation myocardial infarction or heart attack (NSTEMI)
  • ST segment elevation myocardial infarction or heart attack (STEMI).

The location of the blockage, the length of time that blood flow is blocked and the amount of damage that occurs determines the type of acute coronary syndrome. These life-threatening conditions require emergency medical care.

Unstable Angina

Unstable angina is a new symptom or a change from stable angina. The angina may occur more frequently, occur more easily at rest, feel more severe, or last longer. Although this angina can often be relieved with oral medications, it is unstable and may progress to a heart attack. Usually more intense medical treatment or a procedure is required. Unstable angina is an acute coronary syndrome and should be treated as a medical emergency.

Heart attack

This heart attack, or MI, does not cause changes on an electrocardiogram (ECG). However, chemical markers in the blood indicate that damage has occurred to the heart muscle. In NSTEMI, the blockage may be partial or temporary, and so the extent of the damage relatively minimal.

Heart attack: ST segment elevation myocardial infarction (STEMI)

This heart attack, or MI, is caused by a prolonged period of blocked blood supply. It affects a large area of the heart muscle, and so causes changes on the ECG as well as in blood levels of key chemical markers.

Other terms associated with a heart attack:

Stunned Myocardium

If blood flow is returned to an area of heart muscle after a period of ischemia (lack of blood supply), the heart muscle may not pump normally for a period of days following the event. This is called "stunned" heart muscle or myocardium.

Hibernating Myocardium

After a heart attack, some areas of heart muscle do not pump as they should. Some areas will have permanent damage. Other areas are able to return to their normal function if blood flow is returned to that area (by medications or a procedure). Hibernating myocardium is heart muscle that is "resting" and may possibly return to normal function.

Cleveland Clinic cardiologists specialize in prompt diagnosis and treatment of heart attack and acute coronary syndromes. If you do not find what you are looking for about heart attacks, contact us. We would be happy to help you.

Doctors vary in quality due to differences in training and experience; hospitals differ in the number of services available. The more complex your medical problem, the greater these differences in quality become and the more they matter.

Clearly, the doctor and hospital that you choose for complex, specialized medical care will have a direct impact on how well you do. To help you make this choice, please review our Miller Family Heart and Vascular Institute Outcomes.

Cleveland Clinic Heart and Vascular Institute Cardiologists and Surgeons

Choosing a doctor to treat your coronary artery disease depends on where you are in your diagnosis and treatment.

Click on the following links to learn more about Sections and Departments treat patients with Coronary Artery Disease:

The Miller Family Heart and Vascular Institute offers specialty centers and clinics for patients whose treatment requires the expertise of a group of doctors and surgeons who focus on a specific condition.

See: About Us to learn more about the Sydell and Arnold Miller Family Heart & Vascular Institute.


If you need more information, click here to contact us, chat online with a nurse or call the Miller Family Heart and Vascular Institute Resource & Information Nurse at 216.445.9288 or toll-free at 866.289.6911. We would be happy to help you.

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Diagnostic tests are used to diagnose coronary artery disease and the most effective treatment method.



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Reviewed: 05/16

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