This page was reviewed under our medical and editorial policy by

Faizi A. Jamal, MD, Cardiologist, City of Hope | Duarte

This page was updated on August 18, 2023.

An echocardiogram (echo) is a noninvasive imaging test your oncologist may order to evaluate the strength of your heart. It doesn’t use radiation, and it has no side effects.

The main reason for undergoing a heart echo is to evaluate the muscular contractile function of the heart—how well it pumps blood—because determining whether your heart is strong and normal or dysfunctional and abnormal may affect recommendations for your cancer treatment plan.

Some chemotherapies and immunotherapies are considered cardiotoxic, which means it’s possible for them to damage your heart, weakening its muscle function. Anthracyclines, a common class of chemotherapy drugs, is one such treatment. For breast cancer patients, HER2-blockers such as trastuzumab (Herceptin®) may also impact the heart.

When such therapies are considered for treatment, your doctor may want to check the function of your heart muscle before starting therapy. The information from your echocardiogram will help your cancer care team determine an appropriate treatment plan for you.

Echocardiograms may also be performed during or following therapy. Some patients undergoing certain types of breast cancer treatments, for instance, may have an echocardiogram performed every three months to monitor their heart function.

What is an echocardiogram?

An echocardiogram is an ultrasound of the heart. Other imaging tests—such as X-rays, computed tomography (CT) scans and magnetic resonance imaging (MRI) scans—take primarily static pictures of body parts and organs that aren’t moving, while ultrasound has the ability to image rapidly moving structures.

An ultrasound uses high-frequency sound waves to capture pictures of the heart at a rapid rate, allowing the imaging to keep up with the motion of the heart. Unlike other imaging tests, which involve small amounts of radiation, echocardiograms use no radiation.

Doctors often use echocardiograms to determine the speed at which blood flows through the heart, which helps them evaluate how well the heart and its valves are functioning.

The echocardiogram examines the heart’s left ventricular function in particular. The left ventricle is the heart chamber responsible for pumping blood out of the heart to the rest of the body.

Echocardiogram vs. EKG

An echocardiogram and an electrocardiogram (EKG or ECG) sound very similar, and both examine the heart, but they’re very different tests. An echocardiogram is an ultrasound used to investigate both the structure of the heart and its function. An EKG checks the heart’s electrical activity. An echo produces a moving image of the heart, while an EKG produces a graph showing the heart rate and heart rhythm over the period of the test.

Types of echocardiograms

The three types of echocardiograms that may be ordered for a cancer patient are explained below.

Transthoracic echocardiogram

The most common echocardiogram is a transthoracic echocardiogram (TTE), or transthoracic echo.

During this procedure, typically performed on an outpatient basis, patients are asked to remove their clothing above the waist and put on a hospital gown. They then lie down on a table on their left side, facing the cardiac sonographer conducting the test. The sonographer (a technician) will use an ultrasound probe called a transducer to examine the heart from four different angles on the chest.

The sonographer will place electrodes—small, sticky patches—on the chest. The gel on the tip of the probe is designed to create a connection between the transducer and the skin. No needles, IVs or medications are needed. If imaging quality is suboptimal, your physician may order an echocardiogram with the addition of IV contrast.

Transesophageal echocardiogram

A transesophageal echocardiogram (TEE), a rarer procedure, is performed on an inpatient basis in the operating room in cases where the heart valves need to be examined very closely.

This ultrasound is performed while the patient is under sedation. The ultrasound probe in this procedure is inserted into the mouth and advanced into the esophagus using flexible tubing. The transesophageal echocardiogram more closely examines abnormalities on heart valves or examines tumors or masses within the heart.

Occasionally, a transesophageal echocardiogram may be ordered if a transthoracic echocardiogram was unable to adequately assess the heart’s function.

This test is only ordered by a cardiologist.

Stress echocardiogram

A stress echocardiogram, or stress echo, is essentially a stress test. Unlike the other echocardiograms, a stress echocardiogram is designed to evaluate for coronary artery disease. If you’re having chest pain, and your doctor is suspicious that blockages may be affecting your coronary arteries, he or she may order a stress echo.

The stress echo begins with a transthoracic echocardiogram (a resting echocardiogram). The patient then exercises on a treadmill, and another echo is performed immediately after the exercise to assess the heart’s condition after being stressed.

The post-exercise echo determines whether the function of the heart is normal. If it’s abnormal, the test may suggest possible coronary artery disease.

How to prepare for an echocardiogram

No preparation is required for the transthoracic echo. Leave jewelry at home and wear a comfortable top that’s easy to remove. No fasting is required, and patients are able to take their regular medications.

A transesophageal or stress echo, though, requires fasting for a period of time before the procedure. Patients may also be asked to stop taking some medications.

How long does an echocardiogram take?

A transthoracic echocardiogram takes about 40 minutes to complete, while a stress echocardiogram takes about an hour.

A transesophageal echo lasts approximately 20 minutes, but the entire appointment takes several hours since preparations are required prior to the procedure, and some observation time is advised after the test.

Understanding echocardiogram results

When the heart muscle squeezes, it pushes blood into blood vessels that carry it throughout the body. An echocardiogram is used to determine how efficiently the heart is pumping, reported via a measurement called the ejection fraction (EF), which is the fraction of blood ejected from the heart with each heartbeat.

A normal ejection fraction ranges from about 50 percent to 70 percent.

The exam may also report regurgitation, which occurs when a valve closes and some blood leaks backwards. Most people in the general population have mild amounts of valvular regurgitation, and this is not considered unusual.

The test will be interpreted by a cardiologist, and a report is sent to the ordering physician, usually within a day for an inpatient echo and within two days for an outpatient echo. Your doctor will go over the test results with you.

Cancer treatment may or may not be altered based on the images of the heart produced by the test. The results typically don’t require a delay in cancer therapy, but they may affect the type of treatment the oncologist recommends, whether it’s chemotherapy or another treatment. They may also affect the dosage or frequency of treatment.

If the results identify heart disease, you will likely be referred to a cardiologist, who may prescribe a cardio-protective medication to keep your heart function stable during cancer treatment.

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