Diagnosis

If you have signs or symptoms associated with acute coronary syndrome, an emergency room doctor will likely order several tests. Some tests may be performed while your doctor is asking you questions about your symptoms or medical history. Tests include:

  • Electrocardiogram (ECG). This test measures electrical activity in your heart via electrodes attached to your skin. Abnormal or irregular impulses can indicate poor heart function due to a lack of oxygen to the heart. Certain patterns in electrical signals may indicate the general location of a blockage. The test may be repeated several times.
  • Blood tests. Certain enzymes may be detected in the blood if cell death has resulted in damage to heart tissue. A positive result indicates a heart attack.

The information from these two tests — as well as signs and symptoms — may provide the primary basis for a diagnosis of acute coronary syndrome and may determine whether the condition can be classified as a heart attack or unstable angina.

Other tests may be ordered to characterize the condition more thoroughly, rule out other causes of symptoms, or combine diagnostic and treatment interventions.

  • Coronary angiogram. This procedure uses X-ray imaging to see your heart's blood vessels. A long, tiny tube (catheter) is threaded through an artery, usually in your arm or groin, to the arteries in your heart. A liquid dye, which can be detected by X-rays, is sent through the tube to your arteries. Multiple X-ray images of your heart can reveal blockage or narrowing of the arteries. The catheter may also be used for treatments.
  • Echocardiogram. An echocardiogram uses sound waves, directed at your heart from a wand-like device, to produce a live image of your heart. An echocardiogram can help determine whether the heart is pumping correctly.
  • Myocardial perfusion imaging (MPI). This test shows how well blood flows through your heart muscle. A tiny, safe amount of radioactive substance is injected into your blood. A specialized camera detects the blood as it moves through your heart to reveal whether enough blood is flowing through heart muscles and where blood flow is reduced.
  • Computerized tomography (CT) angiogram. A CT angiogram uses a specialized X-ray technology that can produce multiple images — cross-sectional 2-D slices — of your heart. These images can detect narrowed or blocked coronary arteries.
  • Stress test. A stress test assesses how well your heart functions when you exercise — when your heart needs to work harder. In some cases, you may receive a medication to increase your heart rate rather than exercising. This test is only done when there is no evidence of acute coronary syndrome or another life-threatening heart condition when you are at rest. During the stress test, heart function may be assessed by an ECG, echocardiogram or myocardial perfusion imaging.