The Echocardiogram

The echo test and its uses

Echocardiogram Test. BSIP/UIG/Getty Images

The echocardiogram - also called an echo test - is an extremely useful test for studying the heart's anatomy. It is a non-invasive that is entirely safe, and when interpreted by well-trained cardiologists, it is very accurate.

How Is the Echocardiogram Performed?

The echocardiogram is a simple test to have done. You will lie on an examination table, and a technician will hold a transducer (a device that resembles a computer mouse) against your chest, slowly sliding it back and forth.

(The technician will apply a Vaseline-like gel to your chest to aid in sliding the transducer.) You may be asked to roll on your side during the test, or hold your breath for a few seconds. The test takes 30 to 60 minutes to complete.

How Does the Echocardiogram Work?

The transducer that is placed on your chest sends sound waves toward the heart. Like the sonar on a submarine, the sound waves bounce off the structures of the heart, and are collected by the transducer. These returning sound waves are processed by a computer, and are presented on a computer screen as image of the beating heart.

By moving the transducer over the chest wall and angling it in the right directions, the technician is usually able to image most of the important cardiac structures.

What Are Some of the Variations Used With the Echocardiogram?

Echocardiograms are sometimes used in conjunction with stress tests. An echo test is made at rest, and then is repeated during exercise to look for changes in the function of the heart muscle during periods of exertion.

Deterioration in muscle function during exercise can indicate coronary artery disease.

A special microphone (called a Doppler microphone) can be used during the test to measure the velocity of blood flow in various areas within the heart. This information can be useful in assessing heart valve function - especially if mitral regurgitation or aortic regurgitation are suspected.

A transesophageal echocardiogram can create images of cardiac structures that are difficult to see from a standard echo test, and also offers a way to produce echo images during heart surgery when access to the chest itself is not available to the echocardiographer.

What is the Echocardiogram Good For?

The echocardiogram reveals important information about the anatomy of the heart.

It is especially useful for detecting problems with the heart valves (such as aortic stenosis or mitral valve prolapse). It is also very helpful in evaluating congenital heart disease.

Perhaps the most frequent use of the echocardiogram is in evaluating the overall function of the left ventricle. In particular, the echo test is the test used most often to measure the left ventricular ejection fraction. Because the echo test is noninvasive and safe, the ejection fraction can be measured as often as necessary to assess the effectiveness of various cardiac treatments in patients with heart failure.

What Are Some Limitations of the Echocardiogram?

While the echocardiogram provides a lot of information about cardiac anatomy, it is not able to image of the coronary arteries, or coronary artery blockages.

If imaging the coronary arteries is necessary, a cardiac catheterization is commonly performed.

In patients with certain physical variations (a thick chest wall, for instance, or emphysema), the echocardiogram may be unable to image cardiac structures. If an echo test is needed in these individuals, a transesophageal echocardiogram can be used.


Otto, CM. Textbook of Clinical Echocardiography, 3rd ed, WB Saunders, Philadelphia 2004.

Lang RM, Bierig M, Devereux RB, et al. Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 2005; 18:1440.

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