An echocardiogram is a noninvasive procedure used to assess the heart's
function and structures. During the procedure, a transducer, similar to
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 bounce or "echo"
off of the heart structures. These sound waves are sent to a computer
that can create moving images of the heart walls and valves.
Types of Echocardiography
This is a standard, noninvasive echocardiogram. A technician (sonographer)
spreads gel on your chest and then presses a device known as a transducer
firmly against your skin, aiming an ultrasound beam through your chest
to your heart. The transducer records the sound wave echoes your heart
produces. A computer converts the echoes into moving images on a monitor.
If your lungs or ribs block the view, a small amount of intravenous dye
may be used to improve the images.
Your doctor may have a hard time seeing the aorta and other parts of your
heart using a standard transthoracic echo. Thus, he or she may recommend
transesophageal echo, or TEE. During this test, the transducer is attached
to the end of a flexible tube. The tube is guided down your throat and
into your esophagus (the passage leading from your mouth to your stomach).
This allows your doctor to get more detailed pictures of your heart.
When sound waves bounce off blood cells moving through your heart and blood
vessels, they change pitch. These changes (Doppler signals) can help your
doctor measure the speed and direction of the blood flow in your heart.
Doppler techniques are used in most transthoracic and transesophageal
echocardiograms, and they can check blood flow problems and blood pressures
in the arteries of your heart that traditional ultrasound might not detect.
Sometimes, the blood flow shown on the monitor is colorized to help your
doctor pinpoint any problems (color flow echocardiogram).
Some heart problems — particularly those involving the coronary arteries
that supply blood to your heart muscle — occur only during physical
activity. For a stress echocardiogram, ultrasound images of your heart
are taken before and immediately after walking on a treadmill or riding
a stationary bike. If you're unable to exercise, you may get an injection
of a medication to make your heart work as hard as if you were exercising.
3-D (Three-Dimensional) Echocardiography
3-D echo technique captures three-dimensional views of the heart structures
with greater depth than 2-D echo. The live or "real time" images
allow for a more accurate assessment of heart function by using measurements
taken while the heart is beating. 3-D echo shows enhanced views of the
heart's anatomy and can be used to determine the appropriate plan
of treatment for a person with heart disease.