Preventing and monitoring heart problems

Tell your cancer doctor about any existing heart problems before treatment starts. Some cancer treatments aren’t suitable for people with heart problems.

Your doctors can use a range of tests to check how well your heart is working before, during and after treatment:

  • Blood tests – Certain heart tests can check your heart
  • ECG (electrocardiogram) – This records the rate, rhythm and electrical activity of the heart and can find heart rhythm problems.
  • Ultrasound of the heart (echocardiogram) – This uses ultrasound waves to build up a picture of your heart. It measures how well the heart is pumping.
  • MUGA (multigated acquisition) scan – This shows a moving image of your heartbeat. It’s used to check the muscle function of the heart.
  • CMR (cardiac magnetic resonance) scan – This is an MRI scan of the heart. It uses magnetism to build up detailed pictures. It can give information about blood flow to your heart and its overall health.
  • 24-hour ambulatory blood pressure monitor – This is a device you wear at home which records your blood pressure at regular intervals.

Identifying if you’re at risk

If you have a history of heart disease, high blood pressure or type 2 diabetes, your cancer doctor will need to know about these before you start your cancer treatment. If you have a history of heart disease, your cancer doctor will need to know the type of heart problem, what treatments you’ve had for it or are having, and how stable your heart condition is. They may speak to your GP or cardiologist if you have one. They’ll also arrange for you to have some tests to check your heart function before any treatment is given.

Not all cancer treatments are suitable for people with existing heart problems, as they could make the heart problem worse. Your cancer doctor will let you know if a particular treatment is suitable for you. If it isn’t, they may plan a different treatment for you.

If you have an existing heart problem, your doctor will also make sure that it is being treated effectively before you start your cancer treatment. For example, if you have high blood pressure, you will need to see your GP so that you get treatment to control it.

Tests to check your heart function

Your doctors may use a number of tests to check how well your heart is working before, during and after your treatment.

How often your heart function is monitored will depend on the treatment you are having and whether you already have heart problems.

Blood tests

You may have the following blood tests:

  • Cardiac troponin test – This shows if your heart muscle has been damaged.
  • BNP (B-type natriuretic peptides) tests – This tests if your heart muscle is under strain. It can be used to rule out heart failure. If the test is negative, you don’t have heart failure. If it’s positive, you will need further tests such as a heart ultrasound (an echocardiogram – see below) to assess your heart function.

ECG (electrocardiogram)

This test records the rate, rhythm and electrical activity of the heart. Small sticky pads (electrodes) are placed on the chest, arms and legs. These are connected by wires to an ECG recording machine, which picks up the electrical signals that make your heartbeat. The electrical activity is recorded and printed on to paper. The test takes about five minutes. It can detect heart rhythm problems, including if someone has had a heart attack in the past.

‘I’ve had pretty much every type of ECG going and they’re all as painless and minor as each other.’

Ultrasound of the heart (echocardiogram)

An echocardiogram uses ultrasound waves to build up a detailed picture of your heart. It’s sometimes called an ‘echo’. It gives information about muscle function and how well the heart is pumping.

You will be asked to lie on a couch. When you’re comfortable, some gel will be rubbed on to your chest. A probe is then placed over different areas of your chest. The probe gives off pulses of sound waves, which bounce (or echo) against the structures of the heart. The sound waves are picked up by the probe and shown as pictures on the screen of the echo machine.

The test usually takes 15–30 minutes. It’s usually painless but it may cause you some discomfort if you have had recent surgery on the left-side of your chest. Your doctor can give you painkillers to help with any pain or discomfort.

An echocardiogram measures the function of the heart muscle. A common measurement is Left Ventricular Ejection Fraction (LVEF). This is the percentage of blood leaving your heart every time it contracts. It also detects if there are problems with the heart valves.

‘The whole experience was completely stress-free – no pain, no trouble at all.’

You may have a trans-oesophageal echocardiogram. When you have this test, you will either be given some medicine to make you feel sleepy or you will have a general anaesthetic.

Your doctor will pass an ultrasound probe into your gullet (oesophagus). The gullet is the tube that connects your mouth to your stomach and lies behind your heart. The test gives a detailed image of your heart valves and can see things that are too small to be seen on an echocardiogram.

MUGA (multigated acquistion) scan

In some hospitals, the muscle function of the heart is measured using a MUGA scan. This scan shows a moving image of your heartbeat. It may be used to check that your heart is beating normally before treatment. It can also be used to check for any side effects of treatment by comparing scans done before or after treatment. You will need to have a small amount of a radioactive dye injected into a vein in your arm. A special camera is used to measure how the dye is pumped through your heart and the function of your heart muscle.

CMR (cardiac magnetic resonance) scan

This is an MRI scan of the heart. MRI stands for magnetic resonance imaging. It uses magnetism instead of x-rays to build up detailed pictures of the inside of your heart.

You will be asked to lie on a couch. The couch is moved inside a tunnel-shaped scanner that is open at both ends. The scan can take up to an hour but you will be given a buzzer in case you want to speak to the person operating the scanner. During the scan, you will need to lie still and you will be offered earplugs or earphones to listen to music as the scanner is quite noisy.

For some cardiac MRIs, the doctor will use a dye called a contrast agent. This helps to give a clear picture of the blood flow to your heart and information about the health of your heart muscle. The dye will be injected into a vein in your arm before the scan starts. Your doctor will tell you more about this if you need it.

The scan is painless. Some people feel claustrophobic (afraid of small spaces) inside the scanner. If you think this might affect you, tell your doctor before having the scan. You may be offered a mild sedative drug to help you relax.

24-hour ambulatory blood pressure monitor

Some new cancer drugs can cause your blood pressure to rise. To check your blood pressure, your hospital team may take it every time you have your cancer treatment. But you may need a more accurate assessment of your blood pressure.

This can be done with a portable blood pressure monitor, which you wear for 24 hours while you are at home. The blood pressure cuff (which goes around your arm) inflates and measures your blood pressure every 15–20 minutes during the day and every 30–60 minutes during the night. The measurements are recorded so that they can be checked by your specialist. If your blood pressure is raised, you may need treatment to stop it rising to dangerous levels.

Working together to create information for you

We worked with British Heart Foundation to write our content on heart health.

Thank you to all of the people affected by cancer who reviewed what you're reading and have helped our information to develop.

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Back to Cancer treatment and your heart


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