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The reported prevalence of HCM ranges from 1 in 200 to 1 in 500 people in the general population.^1–2*^† In Australia, ~17 in 10,000 men and ~8 in 10,000 women are estimated to have HCM.^3‡

*The 1995 CARDIA study, a multicenter, US-population-based echocardiography study of 4111 subjects (aged 23-35), identified the prevalence of HCM as 1:500 people in the general population.^1
†The 2015 Semsarian publication identified that the prevalence of HCM gene carriers could be as high as 1:200.^2
‡Results from the multicentre National Echo Database Australia (NEDA) extrapolated to the Australian population.³

Common symptoms of HCM include shortness of breath, rapid heartbeat, chest pain (e.g. pressure, tightness, squeezing), dizziness or light-headedness, unexplained tiredness, and fainting. The symptoms of HCM can continue to affect your day-to-day activities even if you are currently being treated for the condition. If you have unexplained or worsening symptoms, talk to your cardiologist immediately.

HCM can make daily activities challenging and it may impact a person’s quality of life. Symptoms may limit physical activity, make simple tasks more difficult, and, if they worsen over time, impact work and emotional wellbeing.

People with HCM are also more likely to develop abnormal heart rhythms (such as atrial fibrillation, which can lead to blood clots), heart failure, stroke, and in rare cases, sudden cardiac death (SCD). Whilst HCM can develop at any age, in some people, the first sign of it can be through SCD, particularly during teenage years or early adulthood.

HCM is most often caused by genetic mutations (changes in your genes) that affect the heart muscle's structure. These mutations are usually inherited from a parent, but sometimes they can occur spontaneously. It’s important to note that unlike some other heart conditions, HCM is not caused by poor diet or lifestyle choices.

HCM is mostly genetic, meaning it's usually caused by inherited gene mutations. A child of an affected parent will have a 50% chance of inheriting the mutation.⁵ However, in rare cases, it can develop without a known genetic cause. Even in families with a known HCM gene, not everyone with the mutation will develop the condition or experience the same symptoms.

There’s currently no cure for HCM and the thickening of the heart muscle is not reversible. Current treatments focus on managing symptoms, preventing complications, and slowing the progression of the disease. While medications can't reverse the thickening, they can help improve how the heart functions and reduce symptoms like shortness of breath or chest pain (e.g. pressure, tightness, squeezing).

While HCM increases the risk of numerous heart-related complications, most people with this condition are thought to achieve a normal life expectancy with proper medical management.

Most patients with HCM have normal life expectancy without significant limitations or complications. However, a small proportion of people with HCM are at risk for SCD, with an annual risk of <1% per year.⁶

Your cardiologist can assess and manage your risk of SCD based on certain factors such as age, family history, and HCM symptoms. It is therefore important that you monitor and discuss all signs and symptoms with your cardiologist.

Treatments are available to manage symptoms and reduce risks of HCM. Options include medications to control heart rate and rhythm and reduce the excessive contraction of the heart muscle, surgical procedures to reduce obstruction, and implantable devices like ICDs for those at risk of sudden cardiac arrest. Treatments for HCM are constantly evolving, so talk with your cardiologist to determine the best approach for you.

An implantable cardioverter defibrillator or ICD is a small battery-powered device that detects and stops irregular heartbeats, also called arrhythmias. An ICD continuously checks the heartbeat and delivers electric shocks, when needed, to restore a regular heart rhythm. An ICD is a highly effective means of preventing SCD, and approximately 7% of HCM patients per year may need an ICD.⁷ For many patients with HCM who are at higher risk, an ICD can bring their risk of sudden cardiac death down to less than 1% per year.⁸

Septal reduction therapy or SRT is a treatment for people with HCM to make the heart muscle thinner and allow blood to flow more easily, which can help relieve symptoms like chest pain (e.g. pressure, tightness, squeezing), shortness of breath, or dizziness. There are two main ways to do this: a) surgery to remove some of the thickened heart muscle, and b) a procedure where alcohol is used to shrink the thickened area. Not everyone with HCM requires SRT and it is usually considered for those who have severe symptoms and where other medications haven’t worked well enough.

In addition to medication, several lifestyle changes can help manage HCM: limiting alcohol and salt intake, eating a healthy diet, stopping smoking (if you smoke), and minimising caffeine if you're sensitive to it. These changes can help control your blood pressure, reduce fluid retention, and improve overall heart health. Your doctor can provide more specific guidance tailored to your needs.

Moderate exercise can be important for people with HCM, depending on what symptoms they have. If you have HCM, it is important to talk to your cardiologist about what exercise is suitable for you. They can assess your individual risk and recommend safe activities.