An echocardiogram, also known as an "echo" or "cardiac ultrasound," uses high-frequency sound waves to create an image of the heart. It is one of the most widely used diagnostic tests for heart disease.
An echo can:
- Measure the size and shape of the heart
- Evaluate how the heart wall moves
- Assess the heart valves
- Find the location and extent of any damage to heart tissues
Sound waves from the test “bounce” back from different parts of the heart in different ways. The computer reads the sound waves and draws a picture. If the clinic has a Doppler echocardiography machine, the echo can show the speed and direction of blood flow as well as the heart structures.
One key measurement taken from an echocardiogram is the ejection fraction (EF). The heart normally ejects at least one-half of the blood (50-60%) it holds with each beat. One or more heart attacks can cause a decrease in the ejection fraction. When less than one-third of the blood is ejected (30-35%), the risk for sudden cardiac death increases.¹
The Ejection Fraction - Watch the Video [00:15]
If you have a low ejection fraction, your doctor may recommend that you visit a heart rhythm specialist, like an EP doctor. Your heart rhythm specialist may recommend that you receive a cardiac device called an implantable cardioverter defibrillator (ICD) that can prevent sudden cardiac death.
Echocardiography can help the doctor find diseases of the heart valves. The doctor can watch how the blood flows through the heart on the echo screen. This procedure can reveal if blood flows backwards through the valve, which is called regurgitation.
Echocardiography can also detect hypertrophic cardiomyopathy.
What to Expect
Most patients are asked to undress from the waist up and wear an exam gown.
- A gel is applied to your chest.
- The doctor or technician then passes a hand-held device called a transducer over your chest.
- Images of your heart will appear on a video monitor.
Normal Echocardiogram - Watch the Video [00:09]
This is an example of a echocardiogram of a normal heart. The line drawing is an outline of the left ventricle; the straight line highlights the middle of the left ventricle.
Photo/video credit: Angelo Auricchio, MD, PhD, Division of Cardiology, University Hospital, Magdeburg, Germany. 2002.
An echo can be done in the doctor's office or at a patient's bedside in the hospital. It's a painless test that can be done lying down or while exercising. The test takes 30 to 90 minutes.
NOTE: If dye is used or transesophageal (a look into the back of the heart from the throat) catheter placed, the echo procedure is considered invasive.