What is a transthoracic echocardiogram (TTE)?

How an echo looks at the heart.
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A transthoracic echocardiogram (often shortened to TTE) is often just referred to as an echo. Although the word echo can refer to a few different techniques (like a TOE), a TTE is generally what people are referring to.

The test is designed to look at the overall structure and function of your heart and see how well it is working. It can look at the muscle, the valves, the lining of the heart (pericardium), and to a limited extent, the tubes (vessels) that connect up to it.

To do an echo, we use an ultrasound probe that we put in various places on your chest, neck and upper abdomen to take videos of your heart from various angles. To help the sound waves get from the probe to your heart, we use ultrasound gel on top of the probe when we take the pictures.

The procedure is very similar to the ultrasound that pregnant women have to look at the foetus, but instead of the belly, we are pointing the probe at your heart.

Apikal4D
Image by Kjetil Lenes.

A standard transthoracic echocardiogram (TTE) cannot tell if you have blockages in your heart arteries, because it can’t see them – it can only see the heart muscle and the valves. That said, if you do a stress echo (where you exercise and then do the echo to look at your heart when it is pumping fast), you can see if one area is not pumping as well compared to another area, which generally means that it isn’t getting enough blood and there is a blockage.

An echo is an extremely useful test – it uses ultrasound, which means there is no radiation involved. It can look at your heart in real time, meaning it can see exactly what is happening at the time you have the scan. And it doesn’t matter whether if you are on medications or if you have allergies (unless you are allergic to the gel, which is vanishingly rare).

Ultrasound_of_human_heart_apical_4-cahmber_view
Image via Wikimedia Commons.

In particular, it gives us information about:

  • how well your heart muscle, in particular your left ventricle, is pumping (summarised as your ejection fraction)
  • the size and thickness of this main pumping chamber
  • if there is any leakiness (called regurgitation), or narrowing (called stenosis) of the valves in your heart
  • if there is any fluid around your heart (in the pericardium)
  • and in some (but not all cases), information how stiff the heart muscle is and what the pressure is like inside the heart

The test takes between 45 minutes and an hour. This can depend on how many pictures the sonographer (the person doing your scan) needs to take, which can vary depending on how easy you are to take pictures of.

This depends on your physical size (very large patients can be difficult for the ultrasound to penetrate through), the location of the heart within your chest (not everyone is in exactly the same place), the size and position of your lungs (emphysema can make your lungs bigger and put them in the way of your heart), and your position (often lying on your left will make it easier, but not always).

You will be lying on your left side for most of the test, with your left hand raised and tucked behind your head, and your right arm resting on your side.

Echo_setup
Image by the National Heart Lung and Blood Institute.

What should I wear?

  • For men, we will generally ask you to remove your shirt. For ladies, we can just open the front of the shirt to access the chest to put the probe on. Wear something loose and easy fitting that can open at the front.
  • The gel that we use is wiped off your chest at the end but small amounts may get onto your clothes. It doesn’t stain and washes off easily, but ideally wear something that you can change out of.

What’s the experience like?

  • You’ll be in a dark room for the duration of the test, so the sonographer (person doing your scan), and don’t be alarmed if you doze off. At times the sonographer may ask you to change position, or to change your breathing pattern so they can get better pictures.
  • The procedure isn’t painful, but at times the sonographer will push the probe firmly into the chest to get a better picture – if it is uncomfortable, please let them know.
  • Sometimes we take measurements of blood flow within the heart and the machine can make some loud noises – don’t be alarmed.

What else might happen?

  • if you are having a stress echo, then you will just have some quick pictures taken (about ten minutes worth), then you will either ride a bicycle or hop on the treadmill to do some exercise, followed by a few more pictures
  • if we can’t see the heart very well, then occasionally people have an injection of some material that helps us see the pumping chamber (the left ventricle) a little clearer. There are a few different types, but in Australia the most common is called Definity (the brand name for perflutren lipid microspheres). Because the echo uses sound waves, this injection creates something a little noisier for the sound waves to bounce off which helps us see more clearly. The injection isn’t painful (but does require a small needle) and only takes a few minutes at the end of your test.
  • if we suspect that you may have a hole in your heart, like a patent foramen ovale or atrial septal defect, then we can do a bubble study. This involves a fast injection of saline (salt water solution) into a vein in your arm. Again, this isn’t painful, but can feel a bit odd when the injection occurs. Usually this is repeated a few times, and sometimes we will ask you do special breathing maneouvres during the test.

Overall, the transthoracic echocardiogram (TTE) is a very useful, simple, non-invasive, safe test, that can provide us with very useful information about your heart.

 

 

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