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A transoesophageal echocardiogram is a high-resolution heart ultrasound performed from inside the oesophagus, giving a far clearer view of the heart valves, left atrium, and aorta than a standard scan from the chest wall. Delivered in Marylebone by a consultant cardiologist with BSE TOE accreditation, from £1,450. Performed under throat anaesthetic and conscious sedation, with a written report within 24 hours.
Most patients do not need a TOE — start with our standard echocardiogram overview or learn how TOE compares to transthoracic and cardiac MRI imaging. For exertional symptoms, see stress echocardiography.
A standard transthoracic echocardiogram (TTE) images the heart by placing an ultrasound probe on the chest wall. Sound waves must travel through skin, muscle, and lung tissue to reach the heart, which limits image quality for certain structures — particularly the back of the heart, the left atrial appendage, and the thoracic aorta.
A transoesophageal echocardiogram overcomes that limitation by placing a specialised ultrasound probe inside the oesophagus, which sits directly behind the heart. From this position there is no lung or bone in the way, and the probe can acquire far higher-resolution images of valve structures, atrial chambers, and the aorta. TOE is not a routine first-line test — it is reserved for specific clinical questions where the additional detail changes management, and it is always performed after a standard echocardiogram wherever possible.
A transoesophageal echocardiogram is a medical procedure, not just an imaging study. At Sonoworld the probe is inserted and the scan performed by a consultant cardiologist, supported by a second clinician providing sedation monitoring and recovery care.
A transoesophageal echocardiogram is indicated when a standard echocardiogram cannot answer the clinical question, or when the level of detail required exceeds what chest-wall imaging can provide. These are the situations where TOE changes management.
| Clinical Question | Why TOE |
|---|---|
| Left atrial appendage thrombus before cardioversion | The appendage cannot be reliably imaged from the chest wall. TOE is the gold standard for excluding clot before rhythm restoration in atrial fibrillation |
| Suspected infective endocarditis | Detects vegetations, abscesses, and valve perforations with much higher sensitivity than transthoracic imaging, particularly on prosthetic valves |
| Prosthetic valve assessment | Metal components shadow transthoracic views. TOE images the valve from behind, revealing paravalvular leaks, dehiscence, and pannus |
| Pre-surgical mitral valve mapping | Surgeons need detailed leaflet-level anatomy before mitral repair. 3D TOE provides the en-face view of the valve used in the operating theatre |
| Suspected aortic dissection | TOE images the ascending and descending thoracic aorta at high resolution and can identify dissection flaps and entry points (although CT aortogram is usually first-line in the emergency setting) |
| Cryptogenic stroke | In younger stroke patients, TOE with a bubble study looks for a patent foramen ovale, atrial septal defect, or aortic atheroma as potential embolic source |
| Intra-cardiac device planning | Left atrial appendage occlusion, MitraClip, TAVI, and ASD closure are all planned and guided with TOE |
| Unexplained TIA or peripheral embolism | Assessment for intracardiac masses or shunts when transthoracic imaging is unremarkable but clinical suspicion persists |
A clot in the left atrial appendage is the most common reason for a cardioversion to be postponed. Before rhythm restoration in patients who have been in atrial fibrillation for more than 48 hours and are not on adequate anticoagulation, a TOE is used to confirm the appendage is clot-free, allowing cardioversion to proceed safely that day. Guidance on this approach is outlined in NICE NG196.
Where clinical features and blood cultures raise suspicion of endocarditis but transthoracic imaging is inconclusive — particularly on prosthetic valves or where vegetations may be small — TOE substantially increases diagnostic sensitivity and informs the need for surgery.
For patients with significant mitral regurgitation where repair is being considered, 3D TOE maps leaflet prolapse, chordal rupture, and annular dilatation segment by segment. This is the same imaging a surgeon would use intra-operatively — produced in advance so the team arrives at theatre with a repair plan.
In strokes without an obvious cause, a patent foramen ovale (PFO) can provide a route for a clot from the leg veins to reach the brain. TOE with a bubble study is the definitive test for detecting PFO and assessing whether closure would be beneficial.
Transoesophageal and transthoracic echocardiograms are complementary, not alternatives. The vast majority of cardiac imaging questions are answered by a standard transthoracic echocardiogram. TOE is reserved for situations where the standard scan is insufficient. Understanding the difference helps ensure you book the right test the first time.
The standard heart ultrasound. A probe is placed on the chest wall and images are acquired through the skin. No preparation, no sedation, no recovery. Answers the overwhelming majority of cardiac imaging questions — valve function, chamber size, ejection fraction, pericardial effusion, cardiomyopathy.
A specialist procedure performed under throat anaesthetic and conscious sedation. A thin ultrasound probe is passed through the mouth into the oesophagus to image the heart from behind. Reserved for specific questions where standard imaging is insufficient — left atrial appendage thrombus, endocarditis, prosthetic valves, mitral repair planning, and suspected PFO.
If you have not had a standard echocardiogram yet, that is almost always the right first step. A TTE will answer the question in the majority of cases and is the basis on which a decision about whether to proceed to TOE is made. The exceptions where TOE is the first-choice test are small: pre-cardioversion in established atrial fibrillation, planned intra-cardiac device procedures, and specific prosthetic valve follow-up. If you are unsure, call the clinic and we will review your clinical picture and direct you to the correct investigation.
TOE is one of several advanced cardiac imaging modalities. The table below summarises what each test does best, so you can arrive at your appointment with a clear picture of why TOE has been chosen — or whether a different investigation might answer your question more appropriately.
| Test | What It Shows | Invasive? | Best For |
|---|---|---|---|
| Transoesophageal echo (TOE) | High-resolution valve, left atrium, and aortic imaging from inside the oesophagus | Yes — probe in oesophagus, sedation | Endocarditis, left atrial appendage thrombus, prosthetic valves, mitral repair planning, PFO |
| Transthoracic echo (TTE) | Heart structure, valves, chambers, and function from the chest wall | No | First-line for almost all cardiac imaging |
| Stress echocardiogram | Heart function at rest and under exercise or dobutamine stress | No (IV line only for dobutamine) | Inducible ischaemia, valve disease under load |
| Cardiac MRI | Detailed heart anatomy, perfusion, scar, and viability | No (IV contrast) | Cardiomyopathy workup, scar quantification, complex congenital anatomy |
| CT coronary angiography | Anatomy of the coronary arteries — narrowings, plaques, and calcium | No (low-dose X-ray, IV contrast) | First-line in stable chest pain under NICE CG95 |
| Invasive coronary angiography | Direct X-ray imaging of the coronary arteries with intra-coronary contrast | Yes — arterial access | High-risk chest pain; definitive before stenting or bypass surgery |
For a full side-by-side of echo modalities, read our echocardiogram comparison guide. Not sure which test you need? Call 020 3633 4902.
Preparation for a transoesophageal echocardiogram is significantly more involved than for a standard echo. Because the procedure involves sedation and passage of a probe into the oesophagus, you will need to fast, arrange an escort home, and plan not to drive, work, or make important decisions for the rest of the day.
Nothing to eat for at least 6 hours before your appointment. Clear fluids (water, black tea or coffee without milk, clear fruit juice) are allowed up to 2 hours before. An empty stomach is essential — it prevents aspiration during sedation and gives the cardiologist clear views.
Take all regular medications with a small sip of water at the usual time, unless specifically told otherwise. Diabetic medication may need adjustment on the morning of the test — call the clinic in advance if you take insulin or oral hypoglycaemics. Anticoagulants (warfarin, apixaban, rivaroxaban, dabigatran, edoxaban) are usually continued — do not stop without explicit instruction.
Any removable dentures or dental plates must be taken out before the procedure. Tell the clinical team about any loose teeth, crowns, bridges, or recent dental work before you sign consent — the probe passes close to the upper teeth and we take extra care where dental work is fragile.
You must arrange for a responsible adult to collect you and stay with you for the rest of the day. Because you will have had sedation, you cannot drive, cycle, take public transport alone, operate machinery, sign legal documents, or drink alcohol for 24 hours. If you cannot arrange an escort, the appointment will need to be rescheduled — this is a safety requirement, not a policy preference.
Sedation wears off at different rates. For 24 hours after your procedure, please do not:
A mild sore throat for a day or two is normal. Eat and drink normally once the throat anaesthetic has worn off — usually within an hour or two.
The whole appointment takes 2 to 3 hours from arrival to discharge, but the probe itself is only in place for 20 to 30 minutes. The rest of the time is spent on preparation, sedation, and safe recovery. Here is what to expect at each stage.
The consultant cardiologist explains the procedure, discusses the specific question being answered, and walks you through the risks and benefits. You sign a written consent form. A small IV cannula is placed in your arm or hand for sedation and emergency access.
You lie on the procedure couch on your left side. ECG electrodes, blood pressure cuff, and a finger oxygen probe are attached. A short transthoracic echo may be performed first to establish the clinical question and baseline views.
A local anaesthetic spray numbs the back of the throat so you cannot feel the probe passing. Conscious sedation (usually midazolam) is then given through the cannula — you remain awake enough to swallow on command but relaxed and comfortable. Most patients remember very little of the scan itself.
A mouth guard protects your teeth. The flexible probe is gently guided over the back of the tongue and you are asked to swallow — this opens the oesophagus and allows the probe to slide down easily. Imaging is then acquired from multiple levels as the probe is manoeuvred up and down. The scan itself takes 20 to 30 minutes.
The probe is withdrawn at the end of the scan. You are moved to a comfortable recovery chair and monitored until the sedation wears off — typically 45 to 60 minutes. A light snack and drink are offered once your swallow reflex has fully returned and the throat anaesthetic has worn off.
The cardiologist discusses the initial findings with you and your escort before you leave. A formal written report — with images, measurements, and clinical interpretation — is typically issued within 24 hours and sent to your GP or referring cardiologist with your consent.
A transoesophageal echocardiogram performed in an accredited clinic by a consultant cardiologist with BSE TOE accreditation is a safe procedure. Published large series consistently report serious complication rates below 1 in 1,000, with the most common minor issue being a transient sore throat. At Sonoworld the procedure is performed in a fully monitored environment with continuous ECG, blood pressure, and oxygen saturation recording, and with emergency equipment and medication immediately to hand.
Most patients tolerate a TOE well and find the sedation makes the experience far more comfortable than they expect. Recovery from the sedation takes around an hour. A mild sore throat for 24 to 48 hours is common and settles without treatment.
Common (not serious): mild sore throat, hoarse voice, or mouth discomfort for 24–48 hours. Drowsiness from sedation lasting several hours. Uncommon: transient drop in blood pressure or oxygen saturation during sedation, minor dental trauma, minor bleeding from the lip or gum. Rare (well under 1 in 1,000): oesophageal injury, aspiration, reaction to sedation, cardiac arrhythmia. The team is trained and equipped to manage all of these immediately.
Some conditions make passing an oesophageal probe unsafe. At triage, we will ask about:
Many of these are relative rather than absolute — each case is reviewed individually by the cardiologist before the procedure is booked.
Severe chest pain radiating to the back or jaw, sudden breathlessness, collapse, or symptoms of a suspected heart attack or acute aortic dissection need urgent hospital assessment. Do not book a private TOE — call 999 or go to your nearest A&E. A TOE is a planned investigation for stable, specific clinical questions, not an emergency test.
Because TOE is an invasive procedure requiring sedation and a specific clinical indication, we do not offer direct online booking. Please start with an enquiry — a member of the clinical team will review your referral or clinical details, confirm that TOE is the appropriate test, and arrange a suitable date.
Fill in the enquiry form or call us directly. A member of the clinical team will be in touch the same working day to discuss your clinical question and arrange a suitable date.
Price includes consultant cardiologist fee, throat anaesthetic and conscious sedation, all monitoring, recovery care, and a written report within 24 hours. Insurance patients: please bring your authorisation code. See the full echocardiogram cost breakdown.
Insurance patients are welcome. Sonoworld is recognised by most major insurers including Bupa, AXA Health, Aviva, and Vitality. If you have not yet had a standard echocardiogram, that is almost always the right first step — see our private echocardiogram overview to decide which test to book.
A standard (transthoracic) echocardiogram images the heart using a probe placed on the chest wall. It is completely non-invasive, requires no preparation, and answers the vast majority of cardiac imaging questions. A TOE uses a specialised probe passed into the oesophagus to image the heart from behind, producing far higher-resolution views of structures that are difficult to see from the chest — particularly the left atrial appendage, prosthetic valves, and the mitral valve in detail. TOE is only used when a standard echo is not sufficient to answer the specific clinical question.
No. The back of the throat is numbed with local anaesthetic spray and conscious sedation is given through a cannula before the probe is passed. Most patients remember very little of the scan itself and find the experience far more comfortable than they expect. A mild sore throat for a day or two afterwards is common and settles without treatment.
Plan for 2 to 3 hours in the clinic. The probe is only in place for 20 to 30 minutes; the rest of the time is spent on consent and cannulation beforehand, and on safe recovery from sedation afterwards. You will not be able to leave until the sedation has worn off sufficiently and you have tolerated a drink and light snack.
Yes — this is a non-negotiable safety requirement, not a policy preference. Because you will have had sedation, your judgement and reaction times will be impaired for 24 hours even if you feel fine. A responsible adult must collect you from the clinic, take you home, and stay with you for the rest of the day. If you cannot arrange an escort, the appointment will need to be rescheduled. We are happy to discuss alternative arrangements if this is difficult.
No food for at least 6 hours before your appointment. Clear fluids (water, black tea or coffee without milk, clear juice) are allowed up to 2 hours before. An empty stomach is essential for safe sedation and gives the cardiologist clear views. After the procedure, once the throat anaesthetic has worn off and your swallow reflex has fully returned, you can eat and drink normally.
No — anticoagulants (warfarin, apixaban, rivaroxaban, dabigatran, edoxaban) are usually continued. TOE is generally considered safe on full anticoagulation, and in many cases the whole point of the procedure is to check the left atrial appendage before cardioversion while anticoagulation is maintained. Do not stop any blood thinner without explicit instruction from your cardiologist or the clinic team.
No. A TOE is done under conscious sedation, not general anaesthesia. You remain awake enough to breathe for yourself and to swallow on command when the probe is passed, but sedation means you feel relaxed and typically have little or no memory of the scan afterwards. General anaesthesia is not needed and would add unnecessary risk.
The commonest effect is a mild sore throat for 24 to 48 hours afterwards. Other uncommon but possible issues include transient drop in blood pressure or oxygen saturation during sedation, minor dental trauma, and minor mouth or lip bleeding. Serious complications — oesophageal injury, aspiration, or a serious reaction to sedation — are rare and are reported in well under 1 in 1,000 studies in published series. All monitoring and emergency equipment are immediately available throughout the procedure.
No. Sedation impairs judgement, reaction time, and memory for at least 24 hours, even if you feel back to normal. You must not drive, cycle, operate machinery, drink alcohol, sign legal or financial documents, or be solely responsible for the care of young children for 24 hours after the procedure. Your escort will need to take you home and stay with you.
The consultant cardiologist will discuss initial findings with you and your escort before you leave the clinic. A formal written report — with images, measurements, and clinical interpretation — is typically issued within 24 hours. With your consent, a copy is sent directly to your GP or referring cardiologist.
Removable dentures and plates must be taken out before the procedure — please bring a container for them. Permanent crowns, bridges, and implants are usually fine, but flag any loose teeth, recent dental work, or fragile restorations before you sign consent. A mouth guard protects your teeth during the scan, and the probe is handled carefully around any dental work we have been told about.
Please give at least 48 hours' notice where possible, as TOE sessions are staffed by a consultant cardiologist and sedation clinician. Cancellations made within 24 hours of the appointment may be subject to a fee. Call 020 3633 4902 or email info@sonoworld.co.uk to make changes.
29 Weymouth Street
London W1G 7DB
Nearest stations: Regent's Park (Bakerloo) · Great Portland Street (Circle, H&C, Metropolitan) · Baker Street (Jubilee, Bakerloo, Metropolitan)
Open in Google MapsTOE clinics run as scheduled sessions — call for the next available slot.
TOE sits at the advanced end of cardiac ultrasound. Most patients start with a standard echo; stress echo answers functional questions; ECG and Holter answer rhythm questions.
Non-invasive first-line heart ultrasound.
Heart function under exercise or dobutamine.
Heart rhythm & conduction. 5–10 min.
24–72 hr continuous rhythm recording.
Condition explainers and follow-up reading from our cardiovascular patient library.
How AF is diagnosed, why stroke risk matters, and when TOE is used before cardioversion.
What a murmur means, which echo findings rule things in or out, and when TOE adds detail.
Why mitral regurgitation matters, how severity is graded, and when surgery is considered.
What a PFO is, how it is found on TOE bubble study, and when closure is considered.
How endocarditis is diagnosed and the role of transoesophageal imaging in confirmation.
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