Transesophageal Echocardiography (TEE)
Transesophageal echocardiography (TEE) uses high-frequency sound waves (ultrasound) to generate high-quality dynamic images of the heart and its blood vessels. TEE employs an ultrasound transducer to produce sound waves and is positioned on an endoscope (long, thin, flexible instrument) that is guided down the throat into your esophagus.
As the esophagus lies immediately behind the heart, clear images of the heart and its valves can be obtained without the interference of the ribs or lungs. The ultrasound waves are reflected from the structures of the heart and picked up by the transducer; a computer attached to the echo machine converts them into images which are projected onto a monitor.
Types of Transesophageal Echocardiography
Transesophageal echocardiography can be categorized into:
- Two-dimensional (2D) TEE: This is the standard commonly used test that generates 2D images of the heart and its related structures.
- Three-dimensional (3D) TEE: This type produces 3D images that provide additional details about the structure and function of the heart and its blood vessels. It assists in the diagnosis of heart problems such as congenital heart disease, heart valve disease, and also in heart surgery.
Clinical Indications and Applications
Transesophageal echocardiography (TEE) is used as a diagnostic tool and procedural adjunct in guiding a variety of surgical and percutaneous cardiac procedures. The TEE test is used to:
- Evaluate the functioning of heart’s valves and chambers
- Detect blood clots, masses, and tumors located inside the heart
- Evaluate the effectiveness of valve surgery
- Evaluate abnormalities of the left atrium
- Diagnose different types of heart diseases such as stroke (results of blood clots), atrial fibrillation, prosthetic valve dysfunction, infective endocarditis, aortic dissection, myocardial disease, pericardial disease, and congenital heart disease
The common steps involved in performing transesophgeal echocardiography are as follows:
- Patient is asked to gargle with an anesthetic solution that numbs the throat. A pain relieving medication is sprayed at the back of the throat.
- The patient lies down in the left lateral position and is administered a sedative to relax.
- Three electrodes are placed on the chest, attached to an electrocardiograph monitor, that record the electrical activity of the heart.
- The heart rate, blood pressure and oxygen level of the blood are closely monitored.
- A dental suction tip is placed inside the mouth to remove any secretions.
- A thin, lubricated endoscope is inserted into the mouth, down the throat, and into the esophagus.
- The transducer at the end of the endoscope is positioned in the esophagus and is rotated to examine the heart at various angles.
- The transducer transmits the images to the monitor.
Pre- Procedure Instructions
The basic instruction pre-operative instructions are as follow:
- Inform your doctor if you are suffering from esophageal problems such as hiatal hernia, swallowing problems, any allergies, or cancer.
- Take the prescribed medication before the test, with a sip of water.
- Do not eat or drink anything for at least 6 hours before the procedure.
- Avoid alcoholic drinks at least a few days before the procedure.
- Dentures should be removed.
The procedure may take about two hours. It is unsafe to drive after the procedure, so the patient should arrange for a companion to drive them home. Patients should not eat or drink for at least one hour after the test. Later they may start with cool liquids.
Transesophgeal echocardiography (TEE) is a relatively safe procedure, but in very rare cases, it can cause injury and bleeding in the esophagus.