Key information about Hypertrophic Cardiomyopathy

What is hypertrophic cardiomyopathy (HCM)?

HCM is an inherited disease of your heart muscle, where the muscular wall of your heart (the myocardium) becomes thickened, making the heart muscle stiff. This thickening makes it harder for your heart to pump blood out of your heart and around the body. Occasionally the condition can lead to fast and, at time, dangerous heart rhythm problems. In fact, HCM is the most common cause of sudden unexpected death in childhood and in young athletes.

What causes HCM?

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

What are the symptoms of HCM?

HCM is a relatively common genetic condition affecting approximately 1 in 500 of the UK population, although most people who have HCM have few, if any, symptoms. Because the disease develops over time, you may find that symptoms become more noticeable later in life.

Some symptoms you may experience include:

  • Shortness of breath

  • Chest pain

  • Palpitations or abnormal heart rhythm (arrhythmia)

  • Lightheadedness and fainting

The symptoms you experience depend on how thick your heart muscle has become, whether there is an obstruction to the blood leaving the heart and whether there are electrical abnormalities.

How is HCM diagnosed?

The most common way to confirm a diagnosis is through a cardiac MRI or echocardiogram (ultrasound of the heart). Your consultant may also want to carry out an electrocardiogram (ECG), which is a test to record the electrical activity of your heart. Plus, an exercise test where an ECG is recorded while you’re on a treadmill or exercise bike, to see how your heart works when it is more active.

Genetic testing is also available to identify a faulty gene that may be causing HCM. If you are found to have a faulty gene, your consultant may ask for your help to identify close relatives (parents, siblings or children) who may have also inherited this gene, so that they can also be offered treatment.

How is HCM treated?

Currently, there is no cure for HCM, but treatments are available to help control your symptoms and prevent complications. Your treatment will depend on how your heart is affected and what symptoms you have. You may need:

  • Medication. To help control your blood pressure, abnormal heart rhythms or other symptoms you may have.

  • A pacemaker. To control your heart rate.

  • An implantable cardioverter-defibrillator (ICD). A small device placed under the skin to monitor your heart rate and deliver required treatments (pacing, cardioversion or defibrillation). This is required if you are at risk of having a life-threatening abnormal heart rhythm.

This article is intended to inform and give insight but not treat, diagnose or replace the advice of a doctor. Always seek medical advice with any questions regarding a medical condition.