Echocardiography uses sound waves to produce an image of the heart and to see how it is functioning. Depending on the type of echocardiography test they use, doctors can learn about the size, shape, and movement of your heart muscle. This test can also show how the heart valves are working and how blood is flowing through your heart. Echocardiography can also give doctors information about your arteries.
One measurement that is usually taken during an echocardiogram is the heart’s ejection fraction. During the heartbeat’s two-part pumping action, the heart squeezes (contracts) and then relaxes. When your heart contracts, it pumps (or ejects) blood out of its lower chambers, called the ventricles. When your heart relaxes, the ventricles fill up with blood. No matter how strongly your heart contracts, it never ejects all of the blood out of its ventricles. The ejection fraction refers to the percentage of blood that is pumped out of the ventricle with each heartbeat.
Because the left ventricle is the heart’s main pumping chamber, doctors usually measure the ejection fraction of the left ventricle. This is called the left ventricular ejection fraction, or the LVEF. The LVEF for a healthy heart is between 55% and 70%. Your LVEF may be lower if your heart muscle has been damaged by a heart attack, heart failure, or another heart problem.
How does it work?
Doppler ultrasound or “echo”
Echocardiography uses high-frequency sound waves (also called ultrasound) that can provide a moving picture of your heart. The sound waves are sent through the body with a device called a transducer. The sound waves bounce off of the heart and return to the transducer as echoes. The echoes are converted into images on a television monitor to produce pictures of your heart.
One-dimensional or M-mode echocardiography is one beam of ultrasound directed toward the heart. Doctors most often use M-mode echocardiography to see just the left side (or main pumping chamber) of your heart.
Two-dimensional echocardiography produces a broader moving picture of your heart. Two-dimensional echocardiography is one of the most important diagnostic tools for doctors.
Doppler echocardiography measures blood flowing through the arteries and shows the pattern of flow through the heart.
What should I expect?
During the test, you will lie on an examination table. A technician will place small metal disks called electrodes on your chest. These electrodes have wires called leads, which hook up to an electrocardiogram machine. This machine will monitor your heart rhythm during the test.
Next, the technician will put a thick gel on your chest. The gel may feel cold, but it does not harm your skin. Then, the technician will use the transducer to send and receive the sound waves.
The transducer will be placed directly on the left side of your chest, above your heart. The technician will press firmly as he or she moves the transducer across your chest. You may be asked to breathe in or out or to briefly hold your breath during the test. But, for most of the test, you will lie still.
An echocardiogram may take up to 45 minutes to perform. You should not have any pain or discomfort during the test.