DIAGNOSTIC PROCEDURES << BACK Transesophageal Echocardiography (TEE) Transesophageal echocardiography (TEE) uses a tiny ultrasound device, passed through a tube into the patient's esophagus, to produce a clear image of the heart using sound waves. TEE can show the size of the heart, its pumping strength, and the location and extent of any damage to the heart tissues. TEE is also used to find abnormalities in blood flow patterns, such as backwards flow of blood through partly closed heart valves. TEE offers a better image than normal echocardiography because the esophagus is so close to the heart muscle, and is especially useful on patients with a thick chest wall. TEE usually takes between 30 and 60 minutes. The patient is given a mild sedative, and the back of the throat is sprayed with a local anesthetic to suppress the gag reflex. Then a special tube called an endoscope, containing a tiny microphone called a transducer, is passed through the mouth and into the esophagus. It is carefully moved until it is positioned next to the heart. The transducer sends ultrasound waves into the heart, some of which are echoed back to the transducer. Different tissues and blood all reflect ultrasound waves differently, so the echoing waves can be translated into a meaningful image of the heart. This image is shown on a monitor or recorded on paper or tape. The transducer may be moved several times during the test to help get a better view of the heart. After the test, the patient must not eat or drink until the throat anesthetic has worn off and the gag reflex has returned. Patients should not drive or operate heavy machinery for at least 10 to 12 hours and should avoid consuming alcohol for a day or so. Risks may include a sore throat for a few days after the test. In rare cases, the procedure may cause bleeding or perforation of the esophagus or an inflammatory condition known as infective endocarditis. The patient may have an adverse reaction to the sedative or local anesthetic.