Heart Tests for People With Breast Cancer

Chemotherapy, radiation, and other treatments for breast cancer help destroy breast cancer cells. But some of these treatments can be hard on the heart. 

To track your heart health during breast cancer treatment, your oncologist may send you for heart tests. You may also work with a doctor who specializes in treating heart conditions (called a cardiologist or a cardio-oncologist). 

Heart tests before you start treatment can help your healthcare team to best tailor your treatments. Heart tests during and after treatment can help spot serious side effects of breast cancer treatment, says Jennifer Kwan, MD, PhD, a cardio-oncologist at Yale Cancer Center in Connecticut. These side effects include:

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  Heart failure: when your heart doesn’t pump enough blood that the body needs

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  Arrhythmias: when there’s a change in the electrical signals that tell the heart to beat leading to a fast, slow, or irregular heartbeat 

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  Atherosclerosis: the buildup of fatty deposits or plaque in your arteries can cause the arteries to become blocked, which can lead to a heart attack or stroke

There are different heart tests you might have depending on your health history or past treatments. You might have one type of test, or several. 

An echocardiogram, or echo, is a type of ultrasound that looks at how well the heart is squeezing to move blood through the heart. There are several types of echos you might have if you have breast cancer:

Transthoracic echocardiogram (TTE)

Using gel on your chest, the technician moves around a probe in order to see a picture of your heart on a screen. The test takes between 40 and 60 minutes. Those receiving a targeted therapy that blocks HER2 need a TTE before they start treatment and every three months, says David Chuquin, MD, a cardio-oncologist at VCU Health in Virginia. People who are receiving the chemotherapy medicines Adriamycin (chemical name: doxorubicin), Ellence (chemical name: epirubicin), daunorubicin, and mitoxantrone will also have an echocardiogram before they start treatment. This heart testing may be repeated during treatment as well.

Stress echocardiogram

A stress echo shows how hard your heart is beating (stressed) when you exercise. The technician will place electrodes on your skin and will watch your heartbeat on an EKG machine while you exercise on a treadmill or stationary bike for a few minutes. If you’re not able to exercise, you’ll be given a medicine that makes your heart work harder. This test can help your doctor to see if plaque buildup is affecting how well your heart is working. The test takes between 30 and 60 minutes. 

Transesophageal echocardiogram (TEE)

A transesophageal echo involves the use of a probe inserted down your throat to take pictures of your heart. Before this test, you’ll be given medicine to numb your throat and calm you. TEEs may last up to 90 minutes. This test is typically not used as often as a TTE, Chuquin says.

MUGA (multigated acquisition) scans are similar to echos in that they both look at the squeeze of the heart. Your doctor can see how much blood is being pumped out of your heart when it squeezes (beats). It’s used to find out if you have signs of heart failure. 

MUGA uses a low dose of radiation to create a picture of the heart. You’ll have electrodes attached to your chest, and a radioactive substance injected through a vein in your arm. Using a camera and video, the technician can see how the substance moves through your veins. These scans can take from one to three hours.

Cardiac MRIs use magnets and radio waves to create pictures of the heart to see how well the heart is squeezing to pump blood to the rest of the body. You may have a cardiac MRI after an echo if the results of the echo don’t answer your doctor’s questions about the health of your heart. You may also have a cardiac MRI if you’re having symptoms such as shortness of breath, fatigue, or weight gain in a short time. The test takes 30 to 90 minutes to complete. While a cardiac MRI can provide your doctors with a closer look at your heart function, it can take a while to schedule an appointment for one, since they aren’t available at all hospitals or cancer centers. 

Electrocardiograms (ECG or EKG) take a snapshot of the heart’s electrical system at one moment in time. Often, this test is done before cancer treatment starts in case you start having heart symptoms during treatment, according to Dr. Chuquin. It only takes a few minutes for the test.

If you have a baseline ECG and your doctor finds out you have an irregular heartbeat (atrial fibrillation), they can know that you’ve had this condition and it wasn’t because of the cancer therapy. Understanding your risk for heart concerns at the start of treatment can help your team know how closely to monitor you during treatments, Chuquin says.   

You’ll have routine blood tests during cancer treatment. But you may have extra tests to check your heart function before and after treatment. These tests may look at 

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  Troponin: A protein found in heart muscle cells and can increase when there’s damage to the heart

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  Beta natriuretic peptide (BNP): A hormone in your blood that’s released when the heart is working hard to pump blood

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  Cholesterol: A fat-like substance in your blood. High levels of “bad” cholesterol (called LDL or low-density lipoprotein) can lead to plaque buildup in your arteries, which can cause a heart attack, stroke, and other problems.

If these blood tests are out of normal range before treatment, that puts you at an increased risk for a heart concern during or after treatment. Your health care team will use this information to  decide how often to check your blood and get images of your heart, according to Dr. Chuquin. 

Certain medicines used to treat breast cancer may increase your risk of heart problems. These include:

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  Anthracycline chemo medicines Adriamycin (chemical name: doxorubicin) and Ellence (chemical name: epirubicin)

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  Anti-HER2 therapies, such as Herceptin (chemical name: trastuzumab)  

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  The CDK4/6 inhibitor Kisqali (chemical name: ribociclib)

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  Hormonal therapies, such as the aromatase inhibitor Arimidex (chemical name: anastrozole)

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  Immune checkpoint inhibitors, such as Keytruda (chemical name: pembrolizumab)

If you receive radiation therapy, particularly to the left breast (your heart is located on your left side), you may also be at greater risk of long-term heart problems than if you had radiation to the right breast. For instance, some studies show that radiation can increase the risk of plaque buildup in the heart’s blood vessels.

If heart tests reveal that you have a problem during breast cancer treatment, you’ll work with a cardiologist or cardio-oncologist and your oncologist to determine the best next steps.

Treatments for heart problems will depend on how severe the issue might be. Often, Kwan says the treatment is oral medications that help protect the heart, such as beta blockers, ACE (angiotensin converting enzyme) inhibitors, and ARBs (angiotensin receptor blockers). These medications all work to relax blood vessels and decrease how hard the heart has to work. They’re usually the medications healthcare providers begin first, according to Kwan.  

If your heart becomes inflamed (myocarditis) during treatment with immunotherapy, Kwan says you might be prescribed steroids or another medication that helps shut down the immune system. This can help control myocarditis. Your care team can then figure out if it’s safe for you to continue immunotherapy. 

A lot of symptoms of a heart problem “are very similar to symptoms that those receiving chemotherapy feel all the time,” Chuquin says. For instance, you might be feeling short of breath, lightheaded, and tired. That doesn’t mean you should keep these symptoms to yourself. 

If you have concerns about your heart during treatment, tell your doctor or others on your healthcare team. Don’t be afraid to ask questions if they don’t refer you for heart testing. You can also seek out a second opinion if you feel your concerns aren’t being addressed.