What Is Hypertrophic Cardiomyopathy?

  • 1st Revision: Laura Colbran

HCM usually stands for human capital management, but not in this case. It is crucial to be aware of Hypertrophic Cardiomyopathy, as most people affected by it are not aware of it, even though it can cause sudden death.

HCM is a genetic heart disease that causes the heart muscle to thicken, making it harder for the heart to pump blood.

The thickened muscle can also obstruct blood flow out of the heart, leading to symptoms like chest pain, shortness of breath, and fainting.

HCM is a common cause of sudden cardiac arrest in young people and athletes, and can be managed with medication, surgery, and lifestyle changes.


Hypertrophic cardiomyopathy (HCM) is a genetic disorder that causes the heart muscle to become abnormally thick, leading to reduced heart function. It is caused by mutations in genes that control the structure and function of heart muscle proteins. HCM can result in symptoms such as chest pain, shortness of breath, and abnormal heart rhythm. It can also lead to serious complications such as heart failure, blood clots, sudden cardiac death, and stroke. HCM requires ongoing monitoring and management to reduce the risk of complications.1

Causes of hypertrophic cardiomyopathy

The exact cause of HCM is not fully understood, but it is believed to be caused by mutations in genes that control the sarcomere proteins involved in the contraction of the myocytes (heart muscle cells) around the different heart chamber structures. The thickened heart muscle is the cause of ventricular hypertrophy, particularly the left ventricle and septum which have the most muscle. It is also the cause of atrial fibrillation, which is the abnormal heart rhythm caused by a disarray of myocytes in the atria of the heart.2

HCM is caused by a mutation of the following genes:

  • MYBPC3 - this gene provides instructions for synthesising the cardiac myosin-binding protein C, which regulates myocyte contractions
  • MYH7 - this gene provides instructions for synthesising the beta-myosin heavy chain, which is a major component of the heart muscle
  • TNNT2 - this gene provides instructions for synthesising a protein called cardiac troponin T, which is crucial for myocyte contraction
  • TNNI3 - this gene provides instructions for synthesising a protein called cardiac troponin I, which also plays a crucial role in myocyte contraction
  • ACTC1 - this gene provides instructions for making a protein called alpha-cardiac actin, which is important for the heart muscle's structure and function

Signs and symptoms of hypertrophic cardiomyopathy

Some people with HCM may not experience any symptoms at all, while others may have severe symptoms that affect their quality of life. If you are experiencing any of these symptoms, it's important to speak with a healthcare provider for an evaluation and appropriate treatment:3

  • Shortness of breath, enhanced during physical activity
  • Chest pain or discomfort, especially during exercise
  • Rapid or abnormal heart rhythm (arrhythmia)
  • Dizziness or fainting (syncope)
  • Fatigue, weakness, or inability to exercise

Management and treatment for hypertrophic cardiomyopathy

Management strategies for HCM include lifestyle modifications, such as reducing alcohol and managing stress. Medications such as beta-blockers, calcium channel blockers, and antiarrhythmic drugs may be used to control symptoms such as chest pain and arrhythmias.4

For severe symptoms or complications, invasive treatments like septal myectomy or alcohol septal ablation may be recommended. Additionally, implantable devices may be used to monitor arrhythmias.

Regular follow-up appointments with a cardiologist are recommended for those with HCM. The specific management and treatment plan will depend on individual patient factors and the severity of their HCM.

Diagnosis of hypertrophic cardiomyopathy5

The diagnosis of HCM typically involves a combination of medical history, physical examination, and diagnostic tests.

During a physical examination, a healthcare provider may listen to the heart using a stethoscope to check for abnormal sounds or murmurs.

Diagnostic tests that may be used to confirm a diagnosis of HCM include an electrocardiogram (ECG) to detect abnormal electrical activity in the heart, an echocardiogram to assess the thickness of the heart muscle and blood flow, and a cardiac MRI to provide more detailed images of the heart.

In some cases, genetic testing may also be recommended to identify mutations associated with HCM.

Risk factors

Since HCM is a genetic disease, the most significant risk factor for developing HCM is having a family history of the disease. 

Other risk factors may include advanced age, high blood pressure, obesity, and a history of heart disease or heart attacks. 

HCM may also be associated with other medical conditions such as thyroid disease or metabolic disorders.6


HCM can be associated with various complications that can affect the heart's structure and function:7

Heart failure: The thickened heart muscle in HCM can impair the heart's ability to pump blood effectively, leading to heart failure. Symptoms may include shortness of breath, fatigue, and fluid retention.

Arrhythmias: HCM can disrupt the normal electrical signals in the heart, leading to abnormal heart rhythms, such as atrial fibrillation, ventricular tachycardia, or sudden cardiac arrest.

Chest pain: The increased thickness of the heart muscle in HCM can reduce blood flow to the heart, resulting in chest pain or angina.

Blood clots and high blood pressure: HCM can disrupt blood flow in the heart, increasing the risk of blood clots forming and potentially causing strokes or other complications.

Sudden cardiac death: HCM can increase the risk of sudden cardiac death, particularly in younger individuals and athletes.


How can I prevent hypertrophic cardiomyopathy

Since hypertrophic cardiomyopathy (HCM) is a genetic heart condition, it cannot be prevented. However, it is important to be aware of family history and undergo regular cardiac checkups to monitor for any signs of HCM or other heart conditions. Maintaining a healthy lifestyle, including regular exercise, a balanced diet, and avoiding smoking and excessive alcohol consumption, can also help promote overall heart health.

How common is hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is relatively rare, with an estimated prevalence of about 1 in 500 individuals in the general population. However, it is considered one of the most common genetic heart conditions, accounting for a significant proportion of cases of sudden cardiac death in young individuals, particularly athletes. 

When should I see a doctor

If you have a family history of hypertrophic cardiomyopathy (HCM) or experience symptoms such as chest pain, shortness of breath, or fainting, you should consult a doctor promptly for evaluation and management.


Hypertrophic cardiomyopathy (HCM) is a genetic heart disease characterised by the thickening of the heart muscle, which can lead to various complications such as arrhythmias, heart failure, and sudden cardiac death. HCM is caused by mutations in certain genes and is often inherited. Diagnosis involves a combination of medical history, physical examination, and diagnostic tests, while management and treatment may include lifestyle modifications, medications, and potentially invasive procedures depending on the severity of the disease and individual patient factors.


  1. Elliott P, McKenna WJ. Hypertrophic cardiomyopathy. The Lancet [Internet]. 2004 Jun 5 [cited 2023 Apr 26];363(9424):1881–91. Available from: https://www.sciencedirect.com/science/article/pii/S0140673604163587
  2. Konno T, Chang S, Seidman JG, Seidman CE. Genetics of hypertrophic cardiomyopathy. Curr Opin Cardiol [Internet]. 2010 May [cited 2023 Apr 27];25(3):10.1097/HCO.0b013e3283375698. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2932754/
  3. Hypertrophic cardiomyopathy(Hcm) [Internet]. www.heart.org. [cited 2023 Apr 26]. Available from: https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/hypertrophic-cardiomyopathy
  4. Marian AJ. Hypertrophic cardiomyopathy: from genetics to treatment. European Journal of Clinical Investigation [Internet]. 2010 Apr [cited 2023 Apr 27];40(4):360–9. Available from: https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2362.2010.02268.x
  5. Prinz C, Farr M, Hering D, Horstkotte D, Faber L. The diagnosis and treatment of hypertrophic cardiomyopathy. Dtsch Arztebl Int [Internet]. 2011 Apr [cited 2023 Apr 27];108(13):209–15. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078548/
  6. Liu LM, Shen LS, Liu SY, Tu B, Li GL, Hu F, et al. Correlations between low thyroid function and incidence of atrial fibrillation in hypertrophic obstructive cardiomyopathy. Chronic Dis Transl Med [Internet]. 2020 Mar 13 [cited 2023 Apr 27];6(1):35–45. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7096325/
  7. Complications of hcm [Internet]. Hypertrophic Cardiomyopathy Association. [cited 2023 Apr 27]. Available from: https://4hcm.org/complications-of-hcm/
  8. Hypertrophic cardiomyopathy: causes, symptoms & treatments [Internet]. Cleveland Clinic. [cited 2023 Apr 27]. Available from: https://my.clevelandclinic.org/health/diseases/17116-hypertrophic-cardiomyopathy
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Amal Sefrioui

Master of Science (MSc), Bioengineering and Biomedical Engineering, Imperial College London

Amal, MSc, BEng: Amal graduated from Imperial College with a Master's in Biomedical Engineering, specializing in Biomaterials and Cancer Research. She has worked for 8 years in the field of medical engineering, in hospitals and laboratories, working with healthcare companies such as Siemens Healthineers and Roche Diagnostics. She has strong interpersonal skills and presentation skills, which helped her manage customer accounts and provide technical information to all relevant healthcare professionals. She is currently undertaking Medical Writing Experience with Klarity to further enhance her medical communication to the industry.

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