A transoesophageal echocardiogram, usually shortened to TOE, is a detailed ultrasound scan of the heart taken from inside the oesophagus, the food pipe, which lies directly behind the heart. A thin, flexible tube with a small ultrasound probe on its tip is gently passed down the throat, in a similar way to a gastroscopy, so that the probe sits just behind the heart. Because there is no chest wall, ribs, or lung tissue in the way, a TOE produces far clearer and more detailed images of the heart’s structures than a standard scan taken from the outside of the chest, particularly of the heart valves and the upper chambers.

A TOE is usually recommended when a standard echocardiogram has not given enough detail, or when a specific structure such as a heart valve or the left atrium needs to be seen clearly. In our experience at our Warwick Park rooms in Tunbridge Wells, the most common reasons we arrange a TOE are to assess heart valves in fine detail, to look for blood clots in the heart before certain rhythm treatments, and to investigate possible infection on a valve. From working with patients across Kent and East Sussex since 2006 at West Kent Cardiology Partnership, we have found that a TOE frequently provides the decisive information a standard scan cannot, allowing a clear diagnosis and a confident treatment plan.

Why a TOE gives clearer images

The oesophagus sits immediately behind the heart, so placing the ultrasound probe there removes the obstacles that limit a scan taken from the chest. In a standard, or transthoracic, echocardiogram, the sound waves have to pass through skin, muscle, ribs, and lung, all of which can reduce image quality. A TOE bypasses all of this.

This makes it especially valuable for viewing structures towards the back of the heart, such as the left atrium, the small pouch off it called the left atrial appendage, and the mitral valve, all of which can be difficult to see clearly from the front. In our experience, this is where a TOE earns its place, because these are exactly the areas where important problems can be missed on a standard scan.

When a TOE is recommended

There are several situations where a TOE is the test of choice. The most common is detailed assessment of the heart valves, including cases where a standard scan has picked up a heart murmur or a leaking or narrowed valve that needs closer inspection, and to check the function of replacement (prosthetic) valves.

A TOE is also routinely used before a cardioversion or an ablation to treat atrial fibrillation. Here the aim is to check for a clot in the left atrial appendage, because restarting a normal rhythm when a clot is present could dislodge it and cause a stroke. This is one of the reasons patients who experience a racing or irregular heartbeat are sometimes advised to have a TOE before treatment.

Other important uses include investigating suspected infective endocarditis, an infection on the heart valves that a TOE detects far more reliably than a standard scan, looking for holes between the chambers such as an atrial septal defect or patent foramen ovale (sometimes found when investigating the cause of a stroke in a younger person), assessing the aorta including suspected dissection, and guiding certain structural heart procedures while they are being carried out.

How to prepare

You will usually be asked not to eat or drink for around four to six hours beforehand, so the stomach is empty. If you are having sedation, which most patients do, you will need someone to take you home afterwards and should not drive for 24 hours. We review your medications in advance, including any blood-thinning tablets, and advise whether anything needs adjusting before the day.

What happens during the procedure

The back of your throat is numbed with a local anaesthetic spray, and a small cannula is placed in the back of your hand so that sedation can be given to help you relax. You lie on your left side, a soft mouthguard is placed between your teeth to protect them and the probe, and the probe is then gently passed down while you swallow to help it on its way. The scan itself usually takes around 20 to 30 minutes. Because of the sedation, most patients remember very little of it.

What happens afterwards

You will rest in a recovery area for around 30 minutes while the sedation wears off. Your throat may feel mildly sore, and you should not eat or drink until the numbing effect has worn off, usually after about an hour, to avoid choking. Almost everyone goes home the same day. If you have had sedation, you should arrange for someone to collect you and avoid driving, alcohol, and important decisions for the rest of the day.

Is a TOE safe?

A TOE is a very safe and routine procedure. The most common after-effect is a mildly sore throat for a day or so. Serious complications, such as injury to the throat or oesophagus, are rare. Our consultants perform these scans regularly, and we take particular care with preparation and monitoring throughout.

Standard echocardiogram or TOE?

A standard echocardiogram remains the first-line heart ultrasound because it is quick, completely non-invasive, and gives excellent information for most purposes. A TOE is reserved for situations where greater detail is needed. In our experience, a TOE works better than a standard echocardiogram for assessing the mitral valve, detecting clots in the left atrium, and diagnosing valve infections, because the probe sits directly behind these structures and produces images a chest-wall scan simply cannot match. From working with patients, we have found that starting with a standard scan and reserving a TOE for when it is genuinely needed gives patients the least invasive route to an accurate answer.

How we arrange a TOE

At our Tunbridge Wells clinic, a TOE is arranged and performed by one of our consultant cardiologists, the same doctor who assesses you and reviews the results with you afterwards. As the only dedicated private cardiac facility in the West Kent area, we are able to offer this alongside the full range of diagnostic tests, so that whatever the initial scan shows, the next step can be organised without delay.

Conclusion

A transoesophageal echocardiogram is a detailed and highly valuable heart scan that provides a much clearer view of certain structures than a standard echocardiogram, particularly the heart valves and the upper chambers. It is a safe, routine, day-case procedure used to assess valves, check for clots before rhythm treatments, and investigate valve infections, among other things. For most people it is straightforward, and the detailed images it provides often make the difference between uncertainty and a clear diagnosis.

If you have been advised to consider a TOE, or you would like a heart problem assessed thoroughly, you can contact us, Dr Clive Lawson and Dr Derek Harrington at West Kent Cardiology Partnership, to arrange a consultation at our Tunbridge Wells clinic, or call us directly on 01892 526726.