What Is an Echocardiogram and What Does It Show?

Two heart tests, two very different jobs. An ECG traces the heart's electrical signals as a line on a screen. An echocardiogram — most people shorten it to an echo — does something else entirely: it uses sound waves to build a moving picture of the heart itself, beating in real time. If you've already read our guide to what an ECG shows, think of the echo as its counterpart. One listens to the wiring; the other looks at the structure doing the work.

The video at the top of this page shows the standard form of the test. It's a short, 2-minute 5-second instructional recording on the basic transthoracic echocardiogram, made for professional teaching. Rather than following one patient, it walks step by step through transducer positions and the sequential movements used to acquire the standard echo images, alongside an overview of the cardiac anatomy those images need to capture.

Sound in, picture out

The handheld probe you will see in the video is called a transducer. Placed on the chest with a little gel, it sends out high-frequency sound waves and listens for the echoes that bounce back from the heart's walls and valves. A computer turns those returning echoes into live images. No X-rays are involved, and for the person on the examination table the sensation is usually just cool gel and firm pressure as the operator angles the probe to find a clearer window between the ribs.

On the chest or from inside — the two main routes

The version in the anchor video is transthoracic, meaning "through the chest wall," and it is the route most echoes take. A second video on this site, "Transthoracic Echocardiogram General", covers the same ground from another angle — probes, landmarks, and the general windows used to obtain these views.

Sometimes the chest-wall pictures are not detailed enough, and a transesophageal echo is used instead. There, a specialised probe is passed into the gullet, which sits directly behind the heart, so the images can be closer and sharper. That version involves sedation and a prepared, empty stomach, unlike the straightforward transthoracic test. Which route is right is a clinical decision based on the question being asked — the simpler test comes first in most cases.

Structure versus electrics: what shows up, and what does not

Because it is a picture rather than a tracing, an echo is particularly good at showing how the heart is built and how it moves: the size of its chambers, how the muscle contracts, and how the valves open and close as blood passes through. It can also show fluid collecting around the heart. What it does not do is replace the ECG. Rhythm problems are still primarily an electrical question, which is why the two tests are so often ordered together rather than treated as alternatives. Neither test, on its own, gives a complete answer — a clinician reads the images alongside your history, examination, and other results.

You do not, by the way, need to do much to get ready for a standard transthoracic echo. You will usually undress from the waist up, put on a gown, and lie on your side or back while the images are taken. Afterwards, the recorded loops and measurements are reviewed and reported, and that report — not the moving picture alone — is what guides any next steps.

If you have been referred for an echo, it is reasonable to ask what question the test is meant to answer in your case. That one conversation makes the report far easier to understand when it arrives.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician and researcher.

Frequently Asked Questions

Does an echocardiogram hurt?
A standard transthoracic echo is not usually painful. You may feel cool gel and firm pressure from the probe, especially when the operator presses to get a clearer image between the ribs.

Is an echocardiogram the same as an ECG?
No. An ECG records the heart's electrical activity, while an echocardiogram uses ultrasound to create moving pictures of the heart's structure and movement. The two tests answer different questions and are often used together.

What is the difference between a transthoracic and a transesophageal echo?
A transthoracic echo uses a probe on the chest wall. A transesophageal echo uses a probe passed into the gullet, behind the heart, for closer images, and it involves sedation. The transthoracic route is the usual first step.

Do I need to prepare for a transthoracic echocardiogram?
For the standard chest-wall test, little preparation is normally needed. Preparation is different for a transesophageal echo, which requires an empty stomach and sedation — your care team will explain if that version is planned.

Educational only — this article is general information about echocardiograms, not medical advice and not a guide to anyone's diagnosis or treatment. Which heart tests you need, and what your results mean, belong with your own clinician.