What is a transoesophageal ECHO (TOE)?
A transoesophageal echo is an ultrasound scan which gives an excellent picture of the heart without other organs obscuring the view.
A standard echocardiogram is done by applying a probe to the front of the chest. The ultrasound beam travels through the chest wall (skin, muscle, bone, tissue) and lungs to reach the heart. Because it travels through the front of the chest or thorax a standard echocardiogram is also known as a transthoracic echo.
At times, closely positioned ribs, obesity and lung diseases such as emphysema may create technical problems by limiting the transmission of the ultrasound beams to and from the heart. In such cases, a transoesophageal echo (TOE) may be preferred. In this case the echo transducer is placed in the oesophagus or food pipe that connects the mouth to the stomach.
Since the oesophagus sits behind the heart, the echo beam does not have to travel through the front of the chest, avoiding many of the obstacles described above. It offers a much clearer image of the heart, particularly the structures to the back of the heart, such as the left atrium, which may not be seen as well by a standard echo taken from the front of the heart.
The TOE probe is much smaller than the standard Echo equipment and is positioned at the end of a flexible tube (similar to the tube used to examine the stomach during endoscopy). The tube transfers the images from the transducer to the Echo monitor.
A TOE is extremely useful in detecting blood clots, masses and tumours that are located inside the heart. It can also gauge the severity of certain valve problems and help detect infection of heart valves, certain congenital heart diseases (like a hole between the upper chambers of the heart, known as an ASD or atrial septal defect) and a tear (dissection) of the aorta (major artery of the body). TOE is also very useful in evaluating patients who have had mini or major stokes as a result of blood clots. The procedure may detect the clot inside the left atrium that was responsible for the stroke.
You will be asked to lie on your left side. A sedative is given through an intravenous (IV) line to help in relaxation and the throat is sprayed with a local anaesthetic. The TOE probe is gently passed down your throat and the doctor will instruct you to swallow. The use of anaesthesia and the sedative minimizes discomfort and there is usually no pain.
The TOE probe is positioned in the oesophagus, directly behind the heart. By rotating and moving the tip of the transducer,the heart can be examined from several different angles. The heart rate, blood pressure and breathing are monitored during the procedure. Oxygen is given as a preventive measure and suction is used, as needed.
After the procedure, you are advised not to drive for 12 hours (because of the sedatives used). Please avoid eating and drinking for at least two hours, as the throat will still be numb and the food or drink could pass into the lungs.The throat may be sore for 4-6 hours and throat lozenges can be used. It is unusual to experience bleeding, persistent pain or fever. These should be reported to your doctor.
Do not eat or drink for six hours. This will minimize the risk of vomiting and aspirating during the procedure.
Please take your medications with some sips of water, unless specifically instructed to withhold them by your doctor.
Arrange for someone to accompany you and to drive you home if the procedure is performed on an outpatient basis.
Be sure to notify the doctor or nurse if you have any allergies, or if you have any difficulty in swallowing or problems with your mouth, oesophagus or stomach.
Dentures and glasses should be removed.
You should plan to be in the hospital for about two hours. The actual procedure usually lasts 10 to 30 minutes. The remainder of the time is spent in preparation and observation.
TOE is a relatively common procedure and is considered to be safe. However, it does require entrance into your oesophagus and stomach. On occasions, patients may experience breathing problems, abnormal or slow heart rhythm, reaction to the sedative and minor bleeding. In extremely rare cases TOE may cause perforation or tear of the oesophagus.
The results are usually available immediately after the procedure. However, your doctor may prefer to review the tape again before giving a final report. Also, if you are drowsy from the sedative, you may not remember the conversation with your Cardiologist and for this reason, a clinic appointment may be set up for a later time.