Hypertrophic cardiomyopathy (HCM)

Hypertrophic cardiomyopathy (HCM) explained

If you have HCM, the muscular wall of your heart (the myocardium) becomes thickened which can make the heart muscle stiff. This can make it harder for your heart to pump blood out of your heart and around your body.

How thick your heart muscle is and how much of your muscle is affected, is different for everyone. The left ventricle (the heart's main pumping chamber) is almost always affected. The septum (the muscle wall between the left and right sides of the heart) can also be affected.

HCM is a genetic condition caused by a change or mutation in one or more genes and is mostly passed on through families. A child of someone with HCM has a 50 percent chance of inheriting the condition.

About 1 in 500 of the UK population has the condition.

• For information on your nearest clinic for inherited heart conditions and support about genetic testing, call the BHF Genetic Information Service.

HCM symptoms

Most people with HCM have no symptoms or feel stable throughout their life. However, others do have symptoms. The most common symptoms of HCM are:

• chest pain
• light headedness and fainting
• palpitations (feeling your heartbeat pounding or beating more quickly than usual)
• shortness of breath
• fatigue (getting tired easily)
• swelling of the legs, feet, ankles and abdomen.

Some people find that their symptoms worsen in later life. This may be because their heart muscle has slowly become stiffer, making it harder for the heart to pump. The area of heart muscle that is affected by HCM and the amount of thickening or stiffening will affect the symptoms you have.

Other issues that can be caused by HCM

If you have HCM, you may be more at risk of other health issues. They include:

• Abnormal heart rhythms (arrhythmias), like atrial fibrillation or heart block.
• There’s also the rare risk of developing a life-threatening abnormal heart rhythm, which can cause a cardiac arrest and sudden death. This is why it’s important to diagnose people who have HCM, so they can have treatment to stop this from happening.
• Endocarditis, which is an infection of the heart’s inner lining.
• A leaky heart valve (mitral regurgitation). This happens when one of your heart valves does not close properly, letting blood leak back into your heart instead of forwards into your body.

HCM diagnosis

The most common tests for HCM are:

• A physical assessment. Your healthcare professional will do basic tests like listening to your heart and lungs, checking your blood pressure and pulse and asking you about your medical history.
• ECG. A simple and useful test which records the rhythm, rate and electrical activity of your heart.
• echocardiogram. An ultrasound is a scan of your heart to see how it’s working.
• exercise test. An ECG is recorded while you’re on a treadmill or an exercise bike to find any problems with your heart while you’re active.
• MRI scan. A type of scan that creates detailed images of your heart.

Obstructive and non-obstructive HCM

During your diagnosis, your healthcare professional may mention ‘obstructive’ cardiomyopathy and ‘non-obstructive’ cardiomyopathy.

• Obstructive HCM means the blood flow from your heart is reduced by the thickening of your heart’s muscular wall. This can cause more issues like arrhythmias and valve regurgitation.
• Non-obstructive HCM means the blood flow from your heart is not reduced by the thickening of your heart’s muscular wall.

Learn more about the different types of HCM with Cardiomyopathy UK.

Genetic testing for HCM

HCM is a mostly inherited heart condition, which means that it can be passed on through families. If your healthcare professional thinks that you have HCM, you may be offered a genetic test to identify a faulty gene.

If you are found to have a faulty gene, your healthcare professional may ask to talk to your close relatives, such as parents, siblings or children. This is because they may have also inherited the same gene.

If you're a parent, sibling or child of someone who has HCM, it's recommended that you're seen at a specialist inherited heart conditions clinic for an assessment and to talk about the option of genetic testing and screening tests for your heart.

For information on your nearest clinic for inherited heart conditions and support about genetic testing, call the BHF Genetic Information Service. 

HCM treatment

There’s currently no cure for HCM, but treatments are available to help control your symptoms and prevent other health issues. Your treatment will depend on how your heart is affected and what symptoms you have.

You may need:

• Medicines like diuretics, beta blockers and cardiac myosin inhibitors. Medicines such as these can reduce the amount of work your heart does, control your blood pressure, manage abnormal heart rhythms and other symptoms.
• An ICD or CRT if you're at risk of having a life threatening abnormal heart rhythm.
• An LVAD to help your heart pump blood.
• A pacemaker to control your heart rate.
• An ablation (catheter ablation) to treat some kinds of arrhythmias.
• A septal myectomy (a type of heart surgery) to remove part of your thickened muscular wall. 

Living with HCM

Many people with HCM feel fine and have little or no symptoms. Those who have symptoms find that they are managed well with treatment and they're able to have a good quality of life. However, some people have symptoms that get worse over time. It’s important that you let your healthcare professional know if this happens so that they can help you manage them.

You might have to make some small changes to your lifestyle. We’ve included some things to think about below.

Work

You should be able to continue to work, but you may not be able to do manual jobs which involve strenuous activity. Speak to your healthcare professional about the work you do. Find out more about work and a heart condition.

Staying active

You should be able to enjoy most activities, but not some competitive sports and high intensity exercise. It’s best to talk to your healthcare professional about the activity you’d like to do.

Driving

You should be able to continue to drive, but you might not be able to drive a lorry, bus, HGV or commercial passenger vehicle. Talk to your healthcare professional about this or visit the DVLA website.

Sex

You may be worried about having sex while living with HCM, but it’s just as safe to do as other kinds of physical activity. It’s important to know your limitations and do it at a level that’s comfortable for you, so you can enjoy a full and active sex life. Find out more about sex and heart conditions.

Healthy living

Having a healthy lifestyle can help reduce the effects of HCM symptoms and lower your risk of getting other health issues. Learn more cardiomyopathy and healthy living.

Endocarditis

This is a rare infection that causes inflammation of the valves and inner lining of the heart. If you’re living with HCM, you have an increased risk of endocarditis. To reduce the risk of developing endocarditis, your healthcare professional might recommend antibiotics before or after any surgeries or procedures.

Emotional support

Living with a heart condition like HCM can be uncertain and emotionally challenging for you and your loved ones. Learn more about things like stress, loneliness and talking about a condition.

Heart Helpline and more support

If you have any questions or concerns, speak to your healthcare team. You can talk to them about anything, even if it feels uncomfortable or embarrassing. Most people feel much better once they do.

Here are some other ways you can get support:

• Learn more about HCM and get support through Cardiomyopathy UK.
• Speak to our cardiac nurses on Heart Helpline by phone, callback, email or online chat (Monday to Friday, 9am to 5pm).
• Contact us to talk to our customer care advisors, find your local BHF shop and for any comments, compliments and complaints you may have.
• Talk to others with heart conditions by joining a support group or online community.

Beat heartbreak from hypertrophic cardiomyopathy

Want to know how the British Heart Foundation is giving hope to those living with cardiomyopathies? CureHeart is harnessing the latest technologies to make a transformative advancement.

This research was only possible through generous donations from the public. Your donations help us fund hundreds of top scientists all over the UK, working on more than a thousand different research projects, but more still needs to be done.