A transesophageal echocardiogram (TEE) is a specialized ultrasound test that uses sound waves to produce detailed images of the heart’s structure and function, including the chambers, valves, and surrounding blood vessels. Unlike a standard ultrasound, the TEE obtains these images from inside the body. This technique provides high clarity, helping healthcare providers accurately diagnose a wide range of cardiac conditions.
Why the Transesophageal Approach is Necessary
The need for a TEE stems from the limitations of a standard transthoracic echocardiogram (TTE), where the transducer is placed on the chest wall. For a TTE, sound waves must travel through skin, muscle, ribs, and lung tissue, which can scatter or weaken the signal. This often results in images that lack detail, particularly for structures located toward the back of the heart.
The transesophageal approach overcomes this by placing a small ultrasound transducer on the end of a thin, flexible tube guided down the esophagus. The esophagus runs directly behind the heart, positioning the transducer within centimeters of the cardiac structures. This close placement allows for the use of higher-frequency sound waves, generating high-resolution images. This technique is particularly valuable for examining the upper chambers of the heart, the heart valves, and the aorta.
Preparing for and Undergoing the TEE
Preparation for a TEE begins several hours before the procedure, primarily involving fasting. Patients are instructed not to eat or drink anything, including water, for at least six hours prior to the test. This fasting is a safety measure to prevent aspiration, which is the inhalation of stomach contents into the lungs, due to the sedation.
Before the procedure, the patient is connected to monitoring equipment. This includes a blood pressure cuff, a pulse oximeter to track oxygen levels, and electrodes on the chest to monitor the heart’s electrical activity (ECG). A local anesthetic spray is applied to the throat to numb the area and suppress the gag reflex. An intravenous (IV) line is then used to administer a sedative medication, keeping the patient relaxed and drowsy throughout the test.
Once the patient is adequately sedated, the physician gently passes the lubricated probe through the mouth and down the esophagus. The patient remains able to breathe normally while the probe is carefully maneuvered to obtain images of the heart from multiple angles. The imaging itself usually takes about 15 minutes, though the entire process, including preparation and recovery, may take up to 90 minutes.
Specific Conditions Diagnosed by TEE
The TEE provides a close-up perspective that makes it the preferred tool for identifying several specific cardiac issues. One frequent application is searching for blood clots, particularly in the left atrial appendage, which is prone to clot formation in patients with atrial fibrillation. Finding these clots is mandatory before procedures like electrical cardioversion, which could otherwise dislodge the clot and cause a stroke.
The high-resolution images are excellent for assessing heart valve function, allowing physicians to detect signs of infection, such as vegetations associated with endocarditis. TEE clearly shows if a valve is narrowed (stenosis) or if blood is leaking backward (regurgitation).
TEE is also highly sensitive in finding structural defects, such as a Patent Foramen Ovale (PFO) or Atrial Septal Defect (ASD). These are small openings between the heart chambers that can allow blood clots to pass directly to the brain. For patients who have experienced a stroke of unknown cause, TEE is often used to identify a potential embolic source from the heart or the aorta.
Post-Procedure Care and Results
Immediately following the TEE, the patient is moved to a recovery area where nurses monitor vital signs until the effects of the sedative wear off. Patients will feel groggy and must not drive or operate machinery for the next 24 hours. A responsible adult must be available to drive the patient home after the procedure.
A common temporary side effect is a sore throat, which may last for a day or two due to the probe insertion. Patients should not eat or drink anything until the numbing effect in their throat completely wears off (typically a couple of hours) to prevent choking. The cardiologist analyzes the images, and the results are typically sent to the ordering physician, who will discuss the findings and treatment implications with the patient within a few days.