Transesophageal echocardiography is also known as TEE, or heart scan with endoscopy. TEE uses a small ultrasound probe guided into the esophagus to closely evaluate the heart and blood vessels within the chest.
Echocardiography is a procedure used to assess the heart’s function and structures through the use of sound waves. 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 “echo” off of the heart structures. 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.
Transesophageal echocardiography (TEE) uses a probe with a transducer on the end that is guided through the throat and into the esophagus. The TEE transducer works the same as the one used in a regular echocardiogram. However, a clearer image can be obtained, because the sound waves do not have to pass through skin, muscle, or bone tissue.
A TEE can utilize one, or more, of four special types of echocardiography:
- M-mode echocardiography
This is the simplest type of echocardiography, and produces an image that is similar to a tracing rather than an actual picture of heart structures. M-mode echo is useful for measuring heart structures, such as the heart's pumping chambers, the size of the heart itself, and the thickness of the heart walls.
- Doppler echocardiography
The Doppler technique is used to measure and assess the flow of blood through the heart's chambers and valves. The amount of blood pumped out with each beat is an indication of the heart's functioning. Also, Doppler can detect abnormal blood flow within the heart, which can indicate such problems as an opening between chambers of the heart, a problem with one or more of the heart's four valves, or a problem with the heart's walls.
- Color Doppler
Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow. This simplifies the interpretation of the Doppler technique.
- 2-D (2-dimensional) echocardiography
This technique is used to "see" the actual structures and motion of the heart structures. A 2-D echo view appears cone-shaped on the monitor, and the real-time motion of the heart's structures can be observed. This enables the physician to see the various heart structures at work and evaluate them.
TEE is used to evaluate the internal heart structures and path of blood flow in congenital (present at birth) heart defects. TEE is also used during heart surgery to evaluate the effects of surgical intervention to the heart, such as repair of congenital heart defects.
When echo is indicated, but other circumstances (i.e., pulmonary disease) that may interfere with the ability to obtain adequate images are present, a TEE may be more appropriate. Further, certain conditions of the heart, such as mitral valve disease, blood clots or masses inside the heart, dissection (tear) of the lining of the aorta (the artery which carries oxygenated blood from the heart to the body), and implanted prosthetic (artificial) heart valves may be better visualized and assessed with TEE than with regular echocardiograms.
Depending on the results of the TEE, additional tests or procedures may be scheduled to gather further diagnostic information.