Here's a rundown of some more common tests, from simple to high-tech, which may be advised under different circumstances.

Electrocardiogram (ECG or EKG). This fast, painless testrecords the heart's electrical activity through small electrodes placed on your body. It is not usually part of the routine physical xam for healthy people, but may be done if you have symptomsor certain risk factors. It can detect a heart attack (past or present) r be used to diagnose specific problems, including irregular heart rhythms or enlarged heart chambers. A Holter Monitor allows for continuous ECG monitoring, via a small recorder and electrodes that you wear under your clothing for 24 hours (or longer). An event monitor, typically worn for several weeks, records heart activity only when you feel symptoms and push a button.

Exercise stress test. This is an ECG taken while you use a treadmill or stationary bike. It shows how much stress your heart can tolerate before problems develop, such as abnormal blood pressure or irregular heart rhythm, and can determine what a safe level of exercise is for you. Because you are exerting yourself, the effects of coronary blockage are more likely to show up here than in a regular ECG. Stress tests carry a slight risk and must be closely monitored by a physician or technician. Results may be less accurate in women.

Echocardiogram. A device (transducer) beams ultrasound waves at your heart, and the returning echoes are used to create a picture of the heart and its moving valves. If a "color Doppler" is used, blood flow through the heart can be evaluated. There are several kinds of echocardiograms, including a stress echocardiogram, done immediately after a treadmill workout, which can reveal abnormal heart contractions.

Myocardial perfusion. This nuclear imaging test evaluates blood flow to the heart. A small amount of radioactive material is injected in a vein, and then a special camera captures images as the substance passes through your heart and arteries. The test usually consists of two parts: one at rest and one after exercise (or a drug may be given that has a similar effect on the heart as exercise), and the images compared. In a heart free of blockages, there should be little difference at rest and after exercise.

Electron-Beam Computed Tomography (EBCT). This imaging procedure detects calciu deposits in coronary arteries, which may signal the presence of CAD. Studies have found that the higher the calcium, the higher the risk for heart attacks. But the use of EBCT is still being debated because it's unclear how much information it provides for predicting heart disease beyond an evaluation of standard risk factors. And it may expose many people to needless radiation, though the dose is low.

Computed tomography angiography (CTA). Also referred to as rnultidetector scanning, this rapidly developing imaging technology produces high-resolution, three-dimensional computerized pictures of the moving heart and large blood vessels, which reveal the extent and nature of plaque formation or calcium deposits. Contrast material may be injected in a vein to improve the quality of the images. Newer systems produce better images much faster-and with less radiation.

Coronary magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA).This test uses magnetic fields and computers to produce images of the heart and arteries. It can detect valve problems, heart enlargement, and vessel disease, as well as damaged heart tissue and other abnormalities. Contrast material may be injected. An advantage is that it detects CAD without radiation and is not invasive. Though relatively new and expensive, it may turn out to be the preferred way to visualize the coronary arteries, and may one day be useful in diagnosing people who come to the emergency room with chest pain.

Coronary angiogram. This procedure involves inserting a catheter into a vein, which is then guided to the heart. Contrast material is injected to visualize the heart on X-rays and observe the heart, arteries, and valves at work. Angiography is the gold standard for diagnosing CAD,but because it isinvasive and involves some risks, it is done primarily in people who are candidates for coronary bypass surgery or angioplasty.

Testing you probably don't need: Some clinics offer EBCT, full-body CT scans, and ultrasound tests without a doctor's referral. There's no evidence these tests are worthwhile for people at low risk of heart disease-which is why most insurance won't cover them in people who have no symptoms or other significant risk factors. Moreover, tests that use X-rays, particularly fullbody CT scans, can expose you to high levels of radiation, especially when done repeatedly. All diagnostic tests produce false positive results (indicating disease when none is present), but more so in low-risk people. Such a result would lead to further unnecessary and costly procedures, as well as additional worry.

Adapted from the U C Berkeley Wellness Letter, August 2O08

Published 8-10-2008 on the Healing Heart Foundation Website