Medical Oncologist
Medicines
Heart function monitoring on dual HER2 blockade
Pertuzumab and trastuzumab can occasionally weaken the heart's pumping strength, so everyone on dual HER2 blockade has regular heart scans. Serious problems are uncommon, most changes are found before symptoms appear, and many recover after a pause in treatment. This page explains, in general terms, which checks you will have, what results mean and how you can support your heart.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
On this page
- Why is your heart checked on pertuzumab and trastuzumab?
- Four parts of heart monitoring
- What scan results usually lead to
- Heart terms, in plain language
- Honest limits of heart monitoring
- Things that can raise heart risk
- What you can do during treatment
- What people assume about heart checks
- Common questions about heart monitoring on dual HER2 blockade
The short answer
Why is your heart checked on pertuzumab and trastuzumab?
Pertuzumab and trastuzumab block HER2, a protein on breast cancer cells. Heart muscle cells also use HER2-related signals to cope with stress and repair themselves, so blocking HER2 can sometimes weaken the heart's pumping strength. When the two antibodies are given together, which is called dual HER2 blockade, large studies have found that serious heart problems remain uncommon and are not clearly more frequent than with trastuzumab alone. Even so, every person on this treatment has their heart checked. A scan, usually an echocardiogram, is done before starting to record how well your heart pumps. It is then repeated at regular intervals, often about every three months during treatment for early breast cancer, and at intervals your team decides in advanced cancer. The scan measures the ejection fraction, the share of blood pumped out with each beat. Most changes are found on these routine scans before any symptoms appear. If pumping strength falls below a safe level, or drops by a large amount, the antibodies are usually paused, heart medicines may be started, and the scan is repeated after a few weeks. Unlike some chemotherapy effects on the heart, this kind of change often improves once treatment is paused, and many people are able to restart and finish their course. A cardiologist may be involved if the change is larger or does not recover.
A scan before you start
A baseline scan shows your normal pumping strength so later changes can be measured.
Regular scans during treatment
Repeat scans pick up changes early, usually before you feel anything.
Changes often recover
A pause in treatment and heart medicines frequently allow pumping strength to improve.
This page gives general information only. Your oncologist decides how often your own heart is checked.The checks
Four parts of heart monitoring
Heart monitoring is more than a single scan. These pieces work together.
Echocardiogram
An ultrasound scan of the heart using a probe and gel on your chest. It is painless, uses no radiation and takes around half an hour.
MUGA scan
A nuclear medicine scan that measures pumping strength using a small amount of radioactive tracer. It is used where echocardiograms are not suitable.
Using the same type of scan each time makes comparison fairer.ECG and blood pressure
A heart tracing and regular blood pressure checks help spot rhythm problems and strain on the heart.
Your own symptoms
What you notice between scans matters just as much.
Report promptly
- Breathlessness on mild effort or lying flat
- Swollen ankles or sudden weight gain
- Palpitations, chest pain or fainting
Reading results
What scan results usually lead to
Result
What usually happens next
Pumping strength normal and stable
Treatment continues and the next scan is booked as planned
Small fall, still in the normal range
Treatment usually continues, sometimes with an earlier repeat scan
Larger fall or below the safe level
Antibodies paused, heart medicines considered, scan repeated in a few weeks
Recovery on the repeat scan
Treatment is often restarted with continued close checks
No recovery, or heart failure symptoms
Cardiology review and a decision on whether to stop the antibodies
Words you will hear
Heart terms, in plain language
- Ejection fraction
- The share of blood in the main pumping chamber pushed out with each heartbeat.
- Left ventricle
- The heart's main pumping chamber, which sends blood around the body.
- Baseline scan
- The first scan before treatment, used as your personal reference point.
- Heart failure
- When the heart cannot pump well enough, causing breathlessness, tiredness and swelling.
- Cardio-oncology
- A heart specialty focused on protecting the heart during cancer treatment.
- Anthracycline
- A group of chemotherapy medicines, such as doxorubicin, that can also affect the heart.
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Being straight with you
Honest limits of heart monitoring
Heart checks make treatment safer, but they cannot remove every risk or answer every question.
Scans have some variation
Results can differ slightly between machines, operators and days. A small change may reflect measurement differences rather than true weakening.
Pauses can feel worrying
Stopping treatment for your heart can make you anxious about the cancer. Short pauses are planned carefully, and your team weighs both risks together.
Not every change recovers fully
Most improve, but a small number of people have lasting weakening that needs long-term heart care.
What this page cannot tell you
It cannot tell you your own heart risk. Your oncologist, and sometimes a cardiologist, will judge this from your scans, history and other treatments.
Who needs extra care
Things that can raise heart risk
Some people start treatment with a higher chance of heart changes. Knowing this helps your team plan closer checks or involve a heart specialist from the beginning.
Earlier or planned anthracycline chemotherapy
Medicines such as doxorubicin or epirubicin can also strain the heart. For this reason, the HER2 antibodies are usually not given at the same time as these medicines, and a scan is done between them.
Existing heart and blood vessel conditions
High blood pressure, diabetes, previous heart attack, irregular heartbeat or valve disease need good control before and during treatment.
Other factors
Older age, being overweight, smoking and radiotherapy to the left side of the chest can add to risk. Stopping smoking and keeping active are worthwhile steps you can take.
Looking after your heart
What you can do during treatment
You cannot control every heart risk, but everyday choices do support your heart through treatment.
Keep your appointments
Heart scans are timed so results are ready before key cycles. Missing one can delay treatment.
Stay gently active
Regular walking, as your energy allows, supports heart fitness and helps with tiredness.
Keep other conditions controlled
Take blood pressure, diabetes and cholesterol medicines as prescribed, and let your family doctor know about your cancer treatment.
Bring your reports
Carry copies of previous scans, especially if you change hospitals, so results can be compared.
Commonly believed
What people assume about heart checks
Two HER2 antibodies must double the heart risk.
In large studies, adding pertuzumab did not clearly increase serious heart problems compared with trastuzumab alone.
If I feel fine, my heart must be fine.
Early changes usually cause no symptoms, which is why routine scans matter.
A paused treatment is lost for good.
Many people restart once pumping strength recovers.
Heart scans are risky.
An echocardiogram is a simple ultrasound with no radiation.
Questions we are asked
Common questions about heart monitoring on dual HER2 blockade
How often will I have a heart scan?
Most people have a scan before starting and then about every three months while on the antibodies for early breast cancer. In advanced cancer, scans may be spaced differently. People with extra risk factors, or a change on a previous scan, may be checked more often. Your team will give you a schedule.
What is a normal ejection fraction?
In healthy adults it usually sits somewhere above the middle of the range, and laboratories give their own normal range on the report. What matters most on treatment is how your result compares with your baseline scan and whether it stays in the safe range your team uses.
Does an echocardiogram hurt?
No. You lie on your side while a technician moves a probe with cool gel over your chest. You may feel some pressure, and you might need to hold your breath briefly. There are no injections or radiation for a standard echocardiogram, and you can go back to normal activities straight after.
What happens if my heart function drops?
If the fall is significant, pertuzumab and trastuzumab are usually paused. Your team may start medicines that protect the heart, such as an ACE inhibitor or beta blocker, and repeat the scan after a few weeks. If pumping strength recovers enough, treatment is often restarted.
Will I need to see a cardiologist?
Not everyone does. A cardiologist is usually involved if you have existing heart disease, if your baseline scan is borderline, or if a meaningful drop occurs during treatment. Some centres have cardio-oncology services that work closely with the cancer team.
Can heart problems start after treatment ends?
Most changes linked to HER2 antibodies happen during treatment and tend to improve after it. Heart effects from anthracycline chemotherapy can appear years later, so people who had those medicines may be advised to keep up healthy habits and have occasional heart checks in the future.
Is the injection under the skin gentler on the heart?
The combined pertuzumab and trastuzumab injection gives similar medicine levels to the drips, and heart effects appear to be similar. The same scan schedule is followed whichever form you receive, so the method of giving it does not change heart monitoring.
Can I exercise while on these medicines?
Yes, for most people moderate activity such as brisk walking is encouraged and supports heart health. If you develop breathlessness, chest pain or unusual tiredness with exercise, stop and tell your team. People with a known drop in pumping strength should ask how much activity is safe.
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Talk to our team
Speak to a breast cancer specialist
Call the helpline or leave your details, and someone will help you arrange a consultation at the CION centre nearest you. One helpline serves every CION centre.
Call 1800 202 8726
Helpline open 24/7
Sources
- European Medicines Agency — Perjeta: product information
- NHS — Echocardiogram
- Macmillan Cancer Support — Pertuzumab
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.