Echocardiography, also known as an echo test, is an ultrasound examination of your heart to assess the function of the heart structures (see Table 1 below). Sound waves create a moving picture of your heart, giving us information about its size and shape, and how well your heart chambers and valves are working.
An echocardiogram is noninvasive (the skin is not pierced). Also, the procedure is used as a safe method of assessing heart function. Because the patient is not exposed to radiation during an echocardiogram, the procedure is suitable for repeated measurements over time.
Table 1: Echocardiography may provide a range of information about different sections of the heart.
Part of Heart
Feature being examined
Evaluate for blood clot prior to converting atrial fibrillation to normal rhythm
Evaluate for dissection or aneurysm; identify plaque as cause of stroke or embolism
Evaluate for evidence of infection – called vegetations; Evaluate for abnormalities of structure such as tear or rupture of valve or valve structures; Quantify degree of leakiness or narrowing (stenosis)
During the resting portion procedure, a transducer (like a microphone) sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the chest at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to the heart tissues, where the waves echo off of the heart structures. This is why an echocardiogram is also called an echo test.
The transducer picks up the reflected waves and sends them to a computer. The computer interprets the echoes into an image of the heart walls and valves.
After the resting echocardiogram images have been obtained, the person will begin to exercise on a treadmill or stationary bicycle. The physician will compare the resting echocardiogram with the test done immediately after exercise. If a patient is unable to exercise for any reason, the doctor may decide to perform a dobutamine stress echocardiogram, in which dobutamine is administered to mimic the effects of exercise on the heart.
The function of the left ventricle is one of the most important measurements that is made during an echocardiogram. The ejection fraction, or EF, is a common measure of the function of the left ventricle, the main pumping chamber that pumps blood to the entire body. The ejection fraction is the percentage of blood pumped out with each heart beat. The ejection fraction is calculated by the dividing the total amount of blood that fills the main heart chamber by the amount of blood pumped out with each heart beat. The normal ejection fraction is about 60%.