What is Hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy (HCM) is a genetic heart condition characterized by abnormal thickening of the heart muscle, particularly the left ventricle, which can obstruct blood flow and affect the heart’s ability to pump effectively. This inherited cardiovascular disorder affects approximately 1 in 500 people worldwide, making it the most common genetic heart disease. HCM can affect people of all ages, from infants to elderly adults, though symptoms often first appear during adolescence or early adulthood. While many people with HCM live normal lives with proper management, the condition can lead to serious complications including sudden cardiac death, particularly in young athletes.
Key statistics
| Prevalence | 1 in 500 people (0.2% of population) |
| Inheritance pattern | Autosomal dominant (50% transmission risk) |
| Age of onset | Variable; often teens to young adults |
| Sudden death risk | 0.5-1% annually in high-risk patients |
Symptoms
Common symptoms: Exertional dyspnea (shortness of breath during activity), chest pain, fatigue, syncope (fainting), heart palpitations, exercise intolerance.
Many people with HCM experience shortness of breath during physical activity as the thickened heart muscle struggles to fill with blood properly. Chest pain, often described as pressure or tightness, may occur during exertion or at rest. Syncope or near-fainting episodes are particularly concerning symptoms that may indicate dangerous heart rhythm abnormalities. Some patients report feeling their heart racing or skipping beats, especially during physical activity. Fatigue and reduced exercise tolerance are common as the heart becomes less efficient at pumping blood. A heart murmur may be detected during physical examination, though this is often the first sign noticed by healthcare providers rather than a symptom experienced by patients. In some cases, the first manifestation of HCM can be sudden cardiac arrest, particularly in young athletes, which underscores the importance of early detection and screening.
Causes and risk factors
HCM is primarily caused by mutations in genes that encode proteins of the cardiac sarcomere, the basic contractile unit of heart muscle cells. The condition follows an autosomal dominant inheritance pattern, meaning only one copy of a mutated gene from either parent is needed to cause the disease. The most commonly affected genes include MYH7, MYBPC3, TNNT2, and TNNI3, among others, which code for proteins essential to heart muscle contraction.
The main risk factor is having a family history of HCM, as each child of an affected parent has a 50% chance of inheriting the condition. Other risk factors include being male (men tend to develop more severe symptoms earlier), participation in competitive athletics (which may unmask the condition or increase risk of sudden death), and certain ethnic backgrounds, though HCM affects all racial and ethnic groups. Environmental factors such as high blood pressure, excessive alcohol consumption, and certain medications may worsen symptoms in people with underlying HCM.
Prevention
As HCM is a genetic condition, primary prevention is not possible. However, early detection through screening is crucial for preventing complications. Family screening is recommended for all first-degree relatives (parents, siblings, children) of individuals diagnosed with HCM, typically involving electrocardiogram (ECG), echocardiogram, and clinical evaluation. Genetic testing can identify disease-causing mutations in about 60-70% of HCM patients and allows for predictive testing in family members.
Pre-participation cardiac screening for athletes, including ECG and echocardiogram, may help identify HCM before participation in competitive sports. While controversial due to cost and potential for false positives, such screening programs have been implemented in some countries. Genetic counseling is recommended for affected individuals and families to understand inheritance patterns and reproductive options, including preimplantation genetic diagnosis for couples wishing to have children.
Complications
Without proper management, HCM can lead to several serious complications. Sudden cardiac death is the most feared complication, particularly affecting young people and athletes, often due to ventricular arrhythmias triggered by the abnormal heart muscle structure. Heart failure may develop as the thickened muscle becomes less efficient at pumping blood, leading to fluid accumulation in the lungs and body.
Atrial fibrillation is common in HCM patients and increases the risk of stroke due to blood clot formation. The abnormal heart muscle can create turbulent blood flow, potentially leading to blood clots even in the absence of atrial fibrillation. Left ventricular outflow tract obstruction can worsen over time, causing increased symptoms and reduced exercise capacity. Some patients may develop mitral regurgitation as the thickened muscle affects the heart valve’s function. Progressive heart muscle scarring (fibrosis) can lead to further deterioration in heart function over time.
Diagnosis
Diagnosis of HCM typically involves a combination of clinical evaluation, imaging studies, and genetic testing. Echocardiography is the primary diagnostic tool, measuring heart muscle thickness and assessing for obstruction of blood flow. A left ventricular wall thickness of 15mm or greater (or 13mm with a family history) is generally considered diagnostic in adults.
Electrocardiogram (ECG) often shows abnormalities such as left ventricular hypertrophy, abnormal Q waves, or conduction abnormalities, though results can be normal in some patients. Cardiac magnetic resonance imaging (CMR) provides detailed images of heart structure and can detect scarring (fibrosis) that may not be visible on echocardiography. Exercise stress testing helps assess symptoms, blood pressure response, and heart rhythm during physical activity.
Holter monitoring or longer-term rhythm monitoring may detect dangerous arrhythmias that could indicate increased risk of sudden death. Genetic testing can identify disease-causing mutations in sarcomere genes, confirming the diagnosis and enabling family screening. Cardiac catheterization is occasionally needed to assess the degree of obstruction and rule out coronary artery disease, particularly in older patients.
Treatment
Treatment for HCM focuses on symptom relief, preventing complications, and reducing the risk of sudden cardiac death. Beta-blockers such as metoprolol or propranolol are often first-line medications, helping to slow the heart rate and improve filling of the ventricles. Disopyramide may be added to reduce obstruction in patients with significant outflow tract obstruction.
Mavacamten, the first targeted therapy specifically approved for HCM, works by reducing the excessive force of heart muscle contraction and has shown significant improvement in symptoms and functional capacity. Aficamten is another recently approved cardiac myosin inhibitor that offers similar benefits for symptomatic patients with obstructive HCM.
Calcium channel blockers like verapamil may be used in patients who cannot tolerate beta-blockers, though they should be avoided in patients with severe obstruction. For patients at high risk of sudden cardiac death, implantable cardioverter defibrillators (ICDs) can provide life-saving therapy by detecting and treating dangerous heart rhythms.
Surgical options include septal myectomy, where part of the thickened muscle is removed to relieve obstruction, and alcohol septal ablation, which uses alcohol injection to create a controlled small heart attack in the thickened area. Both procedures can significantly improve symptoms in appropriately selected patients.
Prognosis
The prognosis for HCM varies widely depending on the severity of symptoms, degree of obstruction, and presence of high-risk features. Many patients with HCM live normal lifespans with appropriate treatment and lifestyle modifications. The annual mortality rate is generally low (less than 1% per year) in most patients, though it can be higher in those with high-risk features.
Factors associated with better outcomes include early diagnosis, appropriate medical therapy, and avoidance of activities that may trigger dangerous arrhythmias. Patients who undergo successful surgical intervention for obstruction often experience significant improvement in symptoms and quality of life. With advances in medications like mavacamten and aficamten, many patients are experiencing better symptom control and improved exercise capacity.
Regular follow-up with a cardiologist experienced in HCM management is essential for monitoring disease progression and adjusting treatment as needed. The development of heart failure or persistent atrial fibrillation may indicate a need for more intensive management or consideration for heart transplantation in severe cases.
Quality of life
Living with HCM requires ongoing attention to lifestyle modifications and symptom management, but many patients maintain active, fulfilling lives. Regular, moderate exercise is generally encouraged, though competitive athletics and high-intensity activities may be restricted based on individual risk assessment. Swimming, walking, and light jogging are typically well-tolerated activities.
Dietary considerations include limiting alcohol intake, maintaining adequate hydration, and avoiding excessive caffeine, as these can worsen symptoms or trigger arrhythmias. Weight management is important, as excess weight can increase the workload on the heart. Stress management techniques such as meditation, yoga, or counseling may help patients cope with the psychological impact of living with a chronic cardiac condition.
Sleep quality can be affected by symptoms such as shortness of breath when lying flat, and some patients benefit from sleeping with their head elevated. Regular monitoring and medication adherence are crucial for maintaining optimal heart function. Many patients find support groups and connecting with others who have HCM helpful for sharing experiences and coping strategies. Mental health support is important, as anxiety and depression can occur, particularly after diagnosis or when dealing with activity restrictions.
Pregnancy and fertility
HCM generally does not affect fertility, but pregnancy requires careful monitoring and management due to the cardiovascular changes that occur during pregnancy. The increased blood volume and cardiac output during pregnancy can worsen symptoms in some women with HCM, particularly those with significant obstruction.
Most women with HCM can have successful pregnancies with appropriate cardiac monitoring, though delivery at a specialized center with cardiac and obstetric expertise is recommended. Some medications used to treat HCM may need to be adjusted or changed during pregnancy due to potential effects on the developing fetus. Beta-blockers are generally considered safe during pregnancy, while other medications may require modification.
Genetic counseling is strongly recommended for individuals with HCM who are planning to have children, as there is a 50% chance of passing the condition to each child. Preimplantation genetic diagnosis may be an option for couples who wish to avoid passing HCM to their children. Prenatal genetic testing is also available for pregnancies at risk.
Children
HCM can affect children, though symptoms may not appear until adolescence when rapid growth occurs. Pediatric HCM may present differently than in adults, with some children developing heart failure symptoms or growth delays. Family screening typically begins around age 10-12 years, or earlier if symptoms develop, and should be repeated annually during periods of rapid growth.
Children with HCM require specialized pediatric cardiology care, as treatment approaches may differ from adults. Activity restrictions are often the most challenging aspect for young patients and their families, requiring careful balance between safety and normal childhood development. School personnel should be informed about the child’s condition and any activity limitations or emergency action plans.
The psychological impact of HCM diagnosis on children and families can be significant, and counseling or support services may be beneficial. Transition to adult care should be planned carefully to ensure continuity of specialized HCM management.
When to see a doctor
Immediate medical attention should be sought for symptoms such as severe chest pain, fainting or near-fainting episodes, severe shortness of breath, or irregular heartbeat with associated symptoms. Any new or worsening symptoms in someone with known HCM warrant prompt evaluation.
Routine cardiology follow-up is typically recommended every 6-12 months for patients with HCM, with more frequent visits for those with severe symptoms or recent changes in condition. Family members of individuals with HCM should undergo screening evaluation even in the absence of symptoms.
Anyone with a family history of sudden cardiac death, particularly in young people, should discuss cardiac screening with their healthcare provider. Athletes experiencing unusual fatigue, shortness of breath, chest pain, or fainting during exercise should seek cardiac evaluation before continuing sports participation.
Regional context
Data on HCM prevalence specifically in the Caucasus region (Georgia, Armenia, Azerbaijan) and Eastern Mediterranean countries is limited. The global prevalence of 1 in 500 likely applies to these regions as well, though specific genetic variants and their frequencies may differ among populations.
We invite healthcare professionals and researchers from the Caucasus and Eastern Mediterranean regions to contribute their experiences and data to Global Medical Journal to help build a more comprehensive understanding of HCM in these populations. Regional genetic studies and family screening programs would provide valuable insights into local disease patterns and help improve diagnosis and care for patients in these areas.
Research and clinical trials
Current research in HCM focuses on developing new therapies targeting the underlying mechanisms of disease, improving risk stratification, and advancing genetic understanding. Clinical trials are investigating next-generation cardiac myosin inhibitors, gene therapy approaches, and novel surgical techniques.
Research into biomarkers that can predict disease progression and sudden death risk is ongoing, potentially leading to more personalized treatment approaches. Studies of exercise physiology in HCM patients may help refine activity recommendations and identify safe exercise parameters.
Patients interested in participating in clinical trials can search ClinicalTrials.gov for current studies. The Hypertrophic Cardiomyopathy Association maintains information about research opportunities and connects patients with ongoing studies. Genetic research continues to identify new disease-causing genes and better understand the relationship between specific mutations and clinical outcomes.
Frequently asked questions
Can people with HCM exercise safely?
Most people with HCM can engage in regular, moderate exercise, but competitive athletics and high-intensity activities may be restricted based on individual risk assessment. A cardiologist should evaluate exercise safety and provide personalized activity recommendations.
Is HCM always inherited?
While most cases of HCM are inherited in an autosomal dominant pattern, about 5-10% of cases appear to be spontaneous mutations with no family history. However, these patients can still pass the condition to their children.
What is the difference between obstructive and non-obstructive HCM?
Obstructive HCM involves thickening that blocks blood flow out of the heart, while non-obstructive HCM involves thickening without significant blockage. Both types can cause symptoms, but treatment approaches may differ.
How often should family members be screened?
First-degree relatives should undergo initial cardiac screening including ECG and echocardiogram. If normal, repeat screening is recommended every 3-5 years in adults, or annually during adolescence when rapid growth occurs.
Can HCM be cured?
Currently, there is no cure for HCM, but treatments can effectively manage symptoms, improve quality of life, and reduce the risk of complications. Research into potential gene therapies offers hope for future curative treatments.
Support and resources
- Hypertrophic Cardiomyopathy Association: https://www.4hcm.org – Patient education, support groups, and research information
- NORD (National Organization for Rare Disorders): https://rarediseases.org
- Orphanet: https://www.orpha.net – Rare disease information portal
- EURORDIS: https://www.eurordis.org – European rare disease advocacy
- American Heart Association: https://www.heart.org – Cardiovascular health resources
- ClinicalTrials.gov: https://clinicaltrials.gov – Clinical trial information
Related conditions
- Dilated cardiomyopathy
Cite this page
GMJ News Desk. “Hypertrophic cardiomyopathy.” GMJ News — Georgian Medical Journal, 2 June 2026. https://news.gmj.ge/condition/hypertrophic-cardiomyopathy/
Licensed under CC BY 4.0. Free to share with attribution to GMJ News.Sources: Orphanet (orpha.net), OMIM, GeneReviews (NCBI), WHO ICD-11, EULAR/ACR guidelines. Schema.org MedicalCondition structured data included.
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