Trans-Oesophageal Echocardiography (TOE)

The long thin probe to perform this test is placed in the throat once you are sedated.

Transthoracic Echocardiography (TTE) is limited by it’s ability to resolve very small structures and in certain individuals, problems such as the shape of the chest wall, the presence of co-existing lung disease or obesity may prevent accurate pictures being taken. Accordingly, we may order a Trans-Oesophageal Echocardiogram (TOE).

A Trans-Oesophageal Echocardiogram is a special procedure using an ultrasound probe that is swallowed , similar to endoscopy. This small rests in the mid-point of the gullet (oesophagus). From here, it directs a beam of ultrasound to the heart directly and with no structures in the way. It allows a very clear and accurate multi-dimensional picture of the heart to be built up. It also has a much greater resolution and so can see much more of the small structures, such as evidence of heart infection and endocarditis, or the presence and dimensions of holes in the heart, such as Atrial Septal Defects (ASD) and Patent Foramen Ovale (PFO).

Transoesophageal echocardiogram (TOE) showing an atrial septal defect (ASD). The blue colour represents blood going across the hole.

A Trans-Oesophageal Echocardiogram is a slightly more invasive procedure. It involves a morning or afternoon in the hospital. You have to fast for at least 4 hours to make sure the stomach is empty. A small needle will be placed in a vein on the back of the hand. You will sign a form, giving consent and then be taken to the imaging room, where you lie upon a trolley. The back of your throat will be sprayed with a local anaesthetic aerosol, which completely numbs and freezes the back of the throat. Many people can have the procedure performed without sedation, but some prefer to have mild sedation with a very low dose of a short acting sedative. Either way, the narrow probe is placed on the back of the tongue and the patient then swallows the probe, under the guidance and control of the Cardiologist. A series of pictures are then taken and the whole procedure lasts some 15 minutes or so.

At the end of the procedure, the probe is removed and the patient is allowed to recover. Because of the fact your throat has been anaesthetised, you will not be allowed to eat or drink for two hours following the procedure. If you have been given the mild sedative, you will not be able to drive or operate machinery for 24 hours thereafter. It is recommended that a spouse or friend collects you to return you home and keep you company for the rest of the day.

The results are available straight away, but because of the sedation, it is best to discuss them on a separate day with you.