Transoesophageal echocardiogram (TOE)

What is a transoesophageal echocardiogram?

A transoesophageal echocardiogram (TOE, or TEE in American usage) is a specialised ultrasound scan of the heart performed from inside the oesophagus, the food pipe that lies immediately behind the heart. A slim, flexible probe is passed gently down the oesophagus under sedation, placing the ultrasound source within centimetres of the heart's structures. Free of the interference from ribs and lung that limits a standard scan, a TOE produces exceptionally detailed images, including real-time 3D views, of the valves, the atria and the aorta.

A TOE complements, rather than replaces, the standard transthoracic echocardiogram: it is the close-up lens we reach for when a specific question needs a definitive answer.

When is a TOE recommended?

• Valve disease in fine detail: defining exactly why a valve leaks or narrows, and whether it can be repaired, essential planning before valve surgery or keyhole procedures such as TAVI and edge-to-edge mitral repair. See our heart valve disease page.
• Before cardioversion: directly confirming the left atrial appendage is free of clot so cardioversion for atrial fibrillation can proceed safely and promptly.
• Suspected endocarditis: the most sensitive test for infection on heart valves, and for the small vegetations and abscesses that change management.
• Source of stroke: identifying clots, a patent foramen ovale (PFO) or other cardiac sources after an unexplained stroke or TIA.
• Prosthetic valves: assessing mechanical or tissue valves, where metal artefact limits standard imaging, including suspected paravalvular leaks.
• Guiding procedures: TOE guidance underpins many modern structural interventions, from left atrial appendage occlusion to PFO closure.

Preparing for your TOE

Preparation is simple: no food for six hours beforehand (small sips of water are usually allowed until two hours before), a review of your medication, blood thinners usually continue, but tell us everything you take, and arrangements for someone to take you home, as sedation is used. Tell us about any swallowing difficulty or oesophageal condition, as occasionally an alternative test such as a cardiac MRI is more appropriate.

What happens during the test?

A TOE is a day-case test taking around fifteen to twenty minutes of scanning time. Your throat is numbed with local anaesthetic spray and sedation is given through a small cannula, most people doze and remember little. Your oxygen levels, heart rhythm and blood pressure are monitored throughout while the probe is passed and the images are acquired. Afterwards you rest briefly, avoid food and hot drinks until the throat numbness wears off (about an hour), and go home the same day; a mild sore throat for a day is common and settles by itself.

Is it safe?

TOE is a very safe, well-established test performed thousands of times daily worldwide. Minor throat soreness is the usual after-effect; significant complications, such as injury to the oesophagus, are rare (well under one in a thousand), and the sedation is light and carefully monitored. For the questions it answers, the information gained almost always outweighs these small risks, and we will discuss your individual balance openly beforehand.

Frequently asked questions

Will I gag or feel the probe?

This is the most common worry, and the honest answer is that the combination of throat spray and sedation deals with it well. Most patients are drowsy throughout, swallow the probe without distress and afterwards remember little or nothing of the test.

How is a TOE different from a standard echocardiogram?

A standard echocardiogram images the heart through the chest wall and is the right first test in almost every situation. A TOE takes over when a specific structure, a valve, the left atrial appendage, a prosthesis, needs to be seen in close-up detail, because the probe sits directly behind the heart with nothing in the way.

Can I eat and drink afterwards?

Once the local anaesthetic has worn off, usually about an hour after the test, you can eat and drink normally. We suggest starting with cool water and avoiding very hot drinks until sensation is fully back, so you cannot inadvertently scald a numb throat.

Can I drive home after a TOE?

No. Because sedation is used, you must not drive, cycle, operate machinery or make important decisions for twenty-four hours. Please arrange for someone to accompany you home; the clinic can assist with transport arrangements where needed.

What about my teeth and dental work?

A soft mouthguard protects your teeth during the test. Do tell us about loose teeth, crowns or dentures beforehand; dentures are removed for the procedure and damage to dental work is very uncommon.

How long does the whole visit take?

Plan for two to three hours door to door: preparation and consent, fifteen to twenty minutes of scanning, then recovery while the sedation wears off. The images are reviewed the same day, so answers follow promptly.

Are there alternatives if I cannot have a TOE?

Sometimes. Depending on the question being asked, a cardiac MRI, a contrast-enhanced standard echocardiogram or a dedicated cardiac CT can provide part of the answer without a probe. Each has strengths and blind spots, and if a TOE is not suitable for you, for instance because of an oesophageal condition, we will design the imaging pathway that answers your question by another route.

Your results and what happens next

Dr Assomull reviews your images and explains the findings clearly, what they mean, and what, if anything, needs to be done. Because assessment, diagnostics and treatment planning are joined up at 68 Harley Street, next steps, whether valve-team referral, a procedure date or simple reassurance and surveillance, follow without delay, and your imaging travels with you to whichever specialist team is involved.

If a close-up answer about your valves, a possible clot or an unexplained stroke is needed, book a consultation, appointments are usually available within one working day.