Echocardiography (TTE and TOE)

What is an echocardiogram?

An echocardiogram is an ultrasound scan of the heart. It uses sound waves (no x-rays, no radiation) to produce moving images of the heart’s chambers, valves, and surrounding structures. It is the most commonly performed cardiac imaging test and gives us a great deal of information very quickly and safely.

There are two main types:

Transthoracic echocardiogram (TTE) — the probe is placed on the outside of the chest. This is the standard, non-invasive form of the test.
Transoesophageal echocardiogram (TOE, sometimes TEE) — the probe is passed down the food pipe (oesophagus), which sits directly behind the heart. This gives much higher-resolution images of the back of the heart, particularly the mitral valve, the left atrial appendage and the aorta.

What can echocardiography show?

Echocardiography is a remarkably versatile test. In a single study it can assess:

Heart pumping function — the strength of the left and right ventricles, including ejection fraction.
Heart valves — whether any of the four valves are leaking (regurgitation) or narrowed (stenosis), and how severely.
Structural abnormalities — holes between the chambers (such as a patent foramen ovale or atrial septal defect), abnormal connections, or congenital problems.
The pericardium — the lining around the heart, looking for fluid or thickening.
The aorta — the main artery leaving the heart, looking for enlargement (aneurysm) or dissection.
Pressures inside the heart — particularly the pressure in the lungs (pulmonary artery pressure), which is important in breathlessness.
Blood clots — particularly in the left atrial appendage in patients with atrial fibrillation.

Who needs an echocardiogram?

Most patients seen in a cardiology clinic will benefit from an echocardiogram. It is particularly useful for patients with:

Breathlessness — to assess both valve function and pumping function.
A heart murmur — to identify which valve is abnormal and how severely.
Chest pain — as part of the wider assessment.
Palpitations — to rule out underlying structural heart disease.
Known valve disease — for surveillance over time.
Suspected heart failure.
Before any heart procedure or major surgery.

What can I expect from a transthoracic echocardiogram (TTE)?

A TTE is straightforward and is often carried out at the same time as a clinic visit. You will be asked to undress to the waist (a gown is provided) and to lie on your left side on an examination couch. A small amount of warm gel is applied to the chest, and an ultrasound probe is moved over different positions on the chest wall. The sonographer or cardiologist will record images and measurements as they go. The whole study usually takes 20 to 40 minutes. There is no preparation required — you can eat and drink normally beforehand and drive yourself home afterwards.

What can I expect from a transoesophageal echocardiogram (TOE)?

A TOE is used when TTE does not provide all the information needed, and is particularly important for:

Planning complex valve procedures (mitral or tricuspid intervention, TAVI, paravalvular leak closure).
Looking for clot in the left atrial appendage before cardioversion or ablation.
Assessing suspected infection of a heart valve (endocarditis).
Detailed assessment of the aorta.

You will need to fast for around six hours before the test. The throat is numbed with a local anaesthetic spray and you are given sedation through a small cannula in the back of the hand. A flexible probe (slightly thicker than a finger) is then passed gently down the throat into the oesophagus, where it sits directly behind the heart. The procedure itself takes around 15 to 20 minutes. Because of the sedation, you should not drive, operate machinery or sign legal documents for the rest of the day, and you will need someone to take you home.

TOE during procedures

Almost every structural heart procedure Dr Dawkins performs is guided in real time by a TOE — including mitral and tricuspid edge-to-edge repair, paravalvular leak closure, PFO and ASD closure, and left atrial appendage occlusion. In these cases the TOE is performed under the same general anaesthetic as the procedure itself, and is operated by an imaging cardiologist working alongside Dr Dawkins throughout the case.

Are there any risks?

Echocardiography is one of the safest tests in cardiology. TTE has effectively no risk — there is no radiation and no contrast.

TOE is also very safe but, because the probe is passed down the oesophagus, there are small risks of throat soreness afterwards, and very rare risks of damage to the throat or oesophagus. The sedation also carries a small risk. These risks will be discussed with you before the test.