Key takeaways:
Hypertrophic cardiomyopathy (HCM) is a condition that causes parts of the heart wall to be abnormally thick. Most cases are inherited.
Untreated HCM can cause complications like heart failure, fainting, arrhythmias, and sudden cardiac arrest.
Treatments for HCM — including medications, surgery, and implantable cardiac defibrillators — can improve symptoms and save lives.
Save on related medications
Hypertrophic cardiomyopathy (HCM) is a condition where the heart muscle becomes too thick, which can make it harder for the heart to pump blood. It can also cause problems with your heart rhythm. This is why HCM can sometimes cause sudden cardiac arrest in competitive athletes.
HCM is one of the most common heart conditions that affects young people, and it’s usually inherited. But there are ways to help prevent problems and treat HCM so people can live long, healthy lives. Learning about the condition is a great first step in protecting yourself and your loved ones.
What causes hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy is one of the most common inherited heart conditions. It’s caused by changes in genes that control how the heart muscle cells are made. These changes, or mutations, may be present in as many as 1 in 250 people. If a parent has HCM, there’s about a 50% chance their child could inherit a gene linked to HCM.
If you have a gene linked to HCM, you’re more likely to develop the condition. But not everyone is affected in the same way. Even within the same family, HCM can range from mild to severe. There are many different gene changes that can lead to HCM.
HCM isn’t always inherited. It can happen when someone’s normal genes change, or mutate, rather than inheriting that gene change.
But it’s important to know that HCM isn’t caused by lifestyle choices. For example, untreated high blood pressure can make the heart muscle thicker. But in HCM, the heart muscle cells themselves are built differently.
What are the symptoms of hypertrophic cardiomyopathy?
Some people don't know they have HCM, because they don't have symptoms. Others can develop symptoms over time. When HCM symptoms are present, they can include:
Shortness of breath
Chest pain
Fatigue
Dizziness
Palpitations
Fainting, especially after exercise or exertion
What are the types of hypertrophic cardiomyopathy?
HCM affects the heart’s main pumping chamber. This is called the left ventricle. There are two main types of HCM:
Obstructive HCM means that the septum (the wall between the left and right ventricles) is so thick that it blocks blood flow out of the heart. This is the most common form of HCM.
Non-obstructive HCM means that the heart muscle is thicker than normal, but it doesn’t block blood flow. Even so, the heart can become stiff, which can make it harder to pump normally.
There’s a third, less common type of HCM called apical HCM. Here are a few things to know about apical HCM:
In apical HCM, the apex, or tip, of the left ventricle is abnormally thick.
Apical HCM doesn’t block blood flow out of the heart.
In the U.S., apical HCM accounts for less than 10% of cases of HCM. It’s more common in people of Asian descent. It’s also more common in men.
What are the risks and complications of hypertrophic cardiomyopathy?
HCM can be life-threatening, but modern treatments make the risk of dying from HCM very low. As we mentioned, many people don’t even realize they have HCM. But HCM can cause some serious problems, including:
Blood flow blockage: Because the heart muscle is so thick, blood can become blocked when leaving the heart. That can cause shortness of breath and fainting spells. This type of blockage is different from coronary artery disease, which causes blocked arteries.
Atrial fibrillation (AFib): About 1 in 5 people with HCM will have AFib. This is an irregular heart rhythm that can cause blood clots in the heart, which can increase the risk for a stroke. Blood thinners can help reduce this risk.
Heart failure: This happens when the heart becomes so stiff that it can’t pump enough blood to the rest of the body.
Mitral valve problems: The mitral valve is located inside the heart, and it helps keep blood moving in the right direction. Obstructive HCM can sometimes be called a condition called SAM (systolic anterior motion of the mitral valve). This can partly block blood flow and make it harder for blood to leave the heart.
Ventricular tachycardia: This is a potentially life-threatening, irregular heart rhythm. It starts in the ventricles, or main pumping chambers. In the worst cases, it can be fatal if not treated with a cardiac defibrillator.
Stroke: People with apical HCM may have a higher risk for stroke than those with other types of HCM. If the tip of the heart weakens and forms a small bulge, blood can pool and make it easier for clots to form. Blood thinners can help to keep the risk low.
Read more like this
Explore these related articles, suggested for readers like you.
How is hypertrophic cardiomyopathy diagnosed?
You may need testing if you have a family history of HCM, or if a healthcare professional hears a specific type of murmur when listening to your heart.
Tests for hypertrophic cardiomyopathy
HCM can be seen on some common heart tests, like:
Electrocardiogram (EKG): This test measures the heart’s electrical activity. HCM is often first detected by abnormal waves on an EKG. But this test can’t diagnose the problem.
Echocardiogram: This is an ultrasound that looks for a thickened heart muscle. It also checks heart valves and detects obstruction of blood leaving the heart.
Cardiac MRI: This measures the thickness of the heart’s walls more accurately. It can also detect scar tissue.
Heart monitor: If you have HCM, you’ll probably need screening for heart arrhythmias. A heart monitor is a small device you wear to check for abnormal heart rhythms that may not show up during a regular office visit.
Screening for hypertrophic cardiomyopathy
HCM is often inherited from a parent with the condition. Early detection is key, because it can help prevent complications. If you have a first-degree relative with HCM, the first step is usually to have an echocardiogram with a cardiologist (a heart specialist). This is important, even if you don’t have any symptoms or signs of HCM.
Since HCM may not show up until middle age, you may need to repeat the echocardiogram every few years. Genetic testing can also be useful if you or a relative has HCM. But it won’t detect all of the genes that can cause HCM.
Treatment for hypertrophic cardiomyopathy
While the idea of a heart condition can feel scary, the symptoms and risks of HCM can usually be managed safely. With regular care from a cardiologist, most people with HCM can live healthy, full lives.
HCM is treated with both medications and procedures. The right treatment for you will depend on the type of HCM you have, its severity, and your symptoms.
Medications for hypertrophic cardiomyopathy
There are several different classes of drugs that can be helpful for people with HCM. These include:
Beta blockers (like metoprolol and atenolol) are often the first choice for HCM. They slow the heart rate to allow the heart to fill more effectively. They may also improve the heart rhythm and reduce palpitations.
Calcium channel blockers (like verapamil or diltiazem) help the heart muscle to relax, which can improve symptoms. They can also slow the heart rate.
Disopyramide is a medicine that helps the heart squeeze less forcefully. This can reduce blockage of blood flow. It’s usually added when symptoms are more severe or not controlled with other medications.
Cardiac myosin inhibitors like Camzyos (mavacamten) and Myqorzo (aficamten) are a newer type of medicine used to treat obstructive HCM. They can make it easier for the heart to squeeze less forcefully, which improves blood flow. Because cardiac myosin inhibitors need careful monitoring, they’re usually prescribed by a cardiologist who specializes in heart muscle conditions like HCM.
As we mentioned, AFib is common in HCM. If you have AFib, you may also need to take a blood thinner to prevent blood clots. These include drugs like Eliquis (apixaban) or Xarelto (rivaroxaban).
Procedures for hypertrophic cardiomyopathy
There are several procedures and surgeries that can help people with HCM. The choice depends on your symptoms and needs:
Implantable cardioverter-defibrillator (ICD): If you’re at risk for a dangerous heart rhythm called ventricular tachycardia, a cardiologist may recommend an ICD. This is a small device placed under the skin, similar to a pacemaker. It can detect a life-threatening rhythm and deliver a shock to restore a normal heartbeat.
Alcohol septal ablation: This is a minimally invasive procedure done through a heart catheter. A cardiologist injects a small amount of alcohol into a blood vessel that feeds the thickened part of the heart muscle. This shrinks that area and helps improve blood flow out of the heart.
Septal myectomy: This is a type of open-heart surgery. A surgeon removes a small part of the thickened heart muscle to relieve the blockage. It’s often very effective for people with more severe symptoms.
Heart transplant: When other options aren’t working, a heart transplant may be recommended. Fewer than 5% of people with HCM will need a transplant.
Frequently asked questions
Yes, with the proper monitoring and treatment, many people with hypertrophic cardiomyopathy (HCM) can live long, healthy lives. But be sure to check with your healthcare team about any exercise limitations. Most people with HCM should avoid competitive sports and high-intensity exercise.
Yes, for most people with HCM, light to moderate exercise like walking is safe. It can improve your overall health and energy levels. Always check with your healthcare team about what level of activity is right for you.
HCM is usually caused by a genetic change, so it’s not “triggered” by your lifestyle or anything else you do. But symptoms can be brought on by things like intense exercise, dehydration, or stress, especially if you have the obstructive type of HCM.
Losing weight won’t cure HCM, but it can help reduce strain on your heart. A healthy weight may improve symptoms and support your overall heart health.
Yes, with the proper monitoring and treatment, many people with hypertrophic cardiomyopathy (HCM) can live long, healthy lives. But be sure to check with your healthcare team about any exercise limitations. Most people with HCM should avoid competitive sports and high-intensity exercise.
Yes, for most people with HCM, light to moderate exercise like walking is safe. It can improve your overall health and energy levels. Always check with your healthcare team about what level of activity is right for you.
HCM is usually caused by a genetic change, so it’s not “triggered” by your lifestyle or anything else you do. But symptoms can be brought on by things like intense exercise, dehydration, or stress, especially if you have the obstructive type of HCM.
Losing weight won’t cure HCM, but it can help reduce strain on your heart. A healthy weight may improve symptoms and support your overall heart health.
The bottom line
Hypertrophic cardiomyopathy (HCM) is a condition that’s usually genetic. If you have a family history of HCM, talk with a healthcare professional about screening for the condition.
If you’re diagnosed with HCM, there are treatments that can improve your health and well-being. This includes medications, like a newer class of drugs called cardiac myosin inhibitors. Some people also benefit from procedures on the heart to improve symptoms and reduce the risk of complications.
Your care team can help you choose safe ways to stay active and the best options to manage your condition.
Why trust our experts?
References
Amano, Y., et al. (2018). Cardiac MR imaging of hypertrophic cardiomyopathy: Techniques, findings, and clinical relevance. Magnetic Resonance in Medical Sciences.
American Heart Association. (2024). Implantable cardioverter defibrillator (ICD).
Bonaventura, J., et al. (2023). Is hypertrophic cardiomyopathy always a familial and inherited disease? JAHA.
Elsouri, K. N., et al. (2023). Adult onset hypertrophic cardiomyopathy (HCM) not detected by echocardiogram: A case presentation. Cureus.
Finocchiaro, G., et al. (2020). The electrocardiogram in the diagnosis and management of patients with hypertrophic cardiomyopathy. Heart Rhythm.
Guigui, S. A., et al. (2022). Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: A narrative review. Journal of Thoracic Disease.
Hao, L., et al. (2026). Hypertrophic cardiomyopathy: Comprehensive insights into pathogenic genes and genotype-phenotype associations. Frontiers in Cell and Developmental Biology.
Hughes, R. K., et al. (2020). Apical hypertrophic cardiomyopathy: The variant less known. JAHA.
Kindi, H., et al. (2018). Surgical myectomy: Rationale and personalized technique. Global Cardiology Science & Practice.
Konno, T., et al. (2010). Genetics of hypertrophic cardiomyopathy. Current Opinion in Cardiology.
Li, J., et al. (2024). Apical hypertrophic cardiomyopathy: Pathophysiology, diagnosis and management. Clinical Research in Cardiology.
Liang, L. W., et al. (2023). Advanced heart failure therapies for hypertrophic cardiomyopathy: State-of-the-art review and an updated analysis from UNOS. JACC: Heart Failure.
Maron, B., et al. (2012). Hypertrophic cardiomyopathy with longevity to 90 years or older. American Journal of Cardiology.
Maron, B., et al. (2016). What do patients with hypertrophic cardiomyopathy die from? American Journal of Cardiology.
Massera, D., et al. (2025). Disopyramide revisited for treatment of symptomatic obstructive hypertrophic cardiomyopathy: Efficacy and safety in patients treated for at least 5 years. JAHA.
Mateo, J., et al. (2018). Alcohol septal ablation in hypertrophic cardiomyopathy. Global Cardiology Science & Practice.
MedlinePlus. (2021). What is genetic testing?
Ommen, S., et al. (2020). 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy: A report of the American College of Cardiology / American Heart Association Joint Committee on Clinical Practice Guidelines. JACC.
Siontis, K. C., et al. (2014). Atrial fibrillation in hypertrophic cardiomyopathy: Prevalence, clinical correlations, and mortality in a large high‐risk population. JAHA.
Stringer, I., et al. (2025). Apical hypertrophic cardiomyopathy: A rare and hidden cause of stroke. Cureus.
Woodland, M., et al. (2023). New era: Mavacamten for obstructive hypertrophic cardiomyopathy. Cardiovascular & Hematological Agents in Medicinal Chemistry.
