• An electrocardiogram (EKG or ECG). Standard EKGs are noninvasive, quick, safe, painless and inexpensive tests that are routinely done if a heart condition is suspected. An EKG records the heart’s electrical activity as a graph or series of wave lines on a moving strip of paper. However, an EKG can only detect cardiac ischemia if an episode just happens to occur during the few minutes when the EKG is being done.

    Electrocardiogram

  • Exercise stress test. This is the most widely used screening test to detect silent ischemia. The test uses an EKG, but with the patient exercising in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The response of the heart under physical exertion can be measured and evaluated, often with the use of an echocardiogram.

    Alternatively, a pharmacological stress test may be recommended for patients who are unable to perform physical activity. A drug such as dobutamine or adenosine is given to the patient, causing the heart to react as if the person were exercising, though the patient is actually at rest. Some drugs increase the heart rate, and other drugs increase blood flow by causing the coronary arteries to widen.

    Either of these tests can be combined with a nuclear stress test, which includes an additional component that produces images of the heart. These images are particularly clear because they show contrasts between light and dark spots. The contrasts reveal any scarring or reductions in blood flow that occurred before, during or after exertion.

  • Holter monitor. A continuous EKG is temporarily attached to an ambulatory (freely moving) patient for a 24-hour period. This test can detect or diagnose abnormal heartbeats (arrhythmias), as well as episodes of cardiac ischemia. It can also help to evaluate the effectiveness of any medications, especially antiarrhythmics, that the patient may be taking. For longer term monitoring, patients may be outfitted with an event recorder that is activated by the patient only when a cardiac abnormality is detected. The results of these episodes are saved by the recorder so they can be evaluated at a later date by a physician.

  • Computed tomography arteriography (CT-A). This is a relatively new technique that uses a scanner to generate pictures of the carotid arteries, which lie in the neck and supply oxygen-rich blood to the brain. This is nearly identical to a carotid angiogram except that the contrast medium is put into the veins instead of the arteries and therefore has a lower risk of complications. This has become the primary test in some locations and is very likely to have a much more prominent role in the future as a result of the high reliability and availability of CT scanners in the United States.