Hypertrophic cardiomyopathy — or HCM — is a heart condition that’s more common than many people realize. It affects an estimated 1 in 500 people worldwide, making it one of the most prevalent genetic heart disorders. HCM happens when the heart muscle, particularly the walls of the ventricles, becomes thicker than it should be. This thickening can make it harder for the heart to pump blood efficiently and may disrupt the heart’s electrical system, potentially leading to dangerous irregular heartbeats.

What Causes HCM?

HCM is primarily a genetic condition, meaning it runs in families. It is caused by mutations in genes that control the growth and structure of heart muscle proteins. If a parent carries one of these mutations, each of their children has a 50 percent chance of inheriting it. More than 1,500 genetic mutations have been linked to HCM so far, which is one reason the condition can vary so much from person to person — some individuals experience severe symptoms while others live their entire lives without knowing they have it.

In some cases, HCM can develop without a clear family history. Age-related changes, high blood pressure or other factors can occasionally cause the heart muscle to thicken in ways that resemble HCM, though these cases are technically distinct from the genetic form of the disease.

Symptoms of Hypertrophic Cardiomyopathy

One of the biggest challenges with HCM is that many people experience no symptoms at all, especially in the early stages. When symptoms do appear, they can include:

• Chest pain or tightness: Often triggered by physical activity or exertion, this occurs because the thickened heart muscle demands more oxygen than the blood supply can deliver.
• Shortness of breath: Difficulty breathing during exercise or even at rest, caused by increased pressure in the heart chambers.
• Dizziness or lightheadedness: Reduced blood flow from the heart can cause episodes of dizziness, particularly when standing up quickly or during exercise.
• Fainting (syncope): Sudden loss of consciousness can occur due to abnormal heart rhythms or obstruction of blood flow from the heart.
• Heart palpitations: A sensation of rapid, fluttering or pounding heartbeats caused by irregular heart rhythms (arrhythmias).
• Fatigue: Feeling unusually tired even after mild activity, as the heart struggles to pump blood efficiently.

Because these symptoms overlap with many other conditions — asthma, anxiety, deconditioning or even normal responses to exercise — HCM is frequently misdiagnosed or dismissed entirely.

Risk Factors

The primary risk factor for HCM is having a family member with the condition. However, several other factors can influence the severity of the disease or increase the likelihood of complications:

• Family history: A first-degree relative (parent, sibling or child) with HCM or a history of sudden cardiac death significantly increases risk.
• Age: While HCM can be present from birth, symptoms often first appear during adolescence or young adulthood, when the heart undergoes rapid growth.
• Athletic activity: HCM is the leading cause of sudden cardiac death in young athletes. Intense physical exertion can trigger life-threatening arrhythmias in affected individuals.
• High blood pressure: Uncontrolled hypertension can worsen heart muscle thickening in people with or at risk for HCM.

How Is HCM Diagnosed?

Diagnosing HCM requires specific cardiac tests that go beyond a standard physical exam. Key diagnostic tools include:

• Echocardiogram: This ultrasound of the heart is the primary tool for diagnosing HCM. It creates detailed images of the heart’s structure and shows the thickness of the heart walls, how blood flows through the chambers and how well the valves function.
• Electrocardiogram (EKG/ECG): This test records the heart’s electrical activity and can reveal abnormal patterns that suggest HCM, even before symptoms appear.
• Cardiac MRI: Provides highly detailed images of the heart muscle and can detect fibrosis (scarring) that may increase the risk of arrhythmias.
• Genetic testing: DNA analysis can identify specific gene mutations associated with HCM. This is particularly useful for screening family members of someone who has been diagnosed.
• Holter monitor: A portable device worn for 24 to 48 hours that continuously records heart rhythms, helping to detect intermittent arrhythmias.
• Stress testing: Monitoring heart function during exercise can reveal symptoms and abnormalities that may not be present at rest.

Treatment Options

While there is no cure for HCM, several treatment options can effectively manage symptoms, reduce complications and improve quality of life:

• Medications: Beta-blockers and calcium channel blockers are commonly prescribed to slow the heart rate, reduce chest pain and ease shortness of breath. For patients with obstructive HCM, mavacamten (Camzyos) is a newer medication that directly targets the underlying mechanism of excessive heart muscle contraction.
• Septal myectomy: This open-heart surgery removes a portion of the thickened heart wall (septum) to improve blood flow. It is considered the gold-standard treatment for patients with severe obstructive HCM who do not respond to medications.
• Alcohol septal ablation: A less invasive alternative to surgery, this catheter-based procedure injects alcohol into a small artery that feeds the thickened area of the heart, causing it to shrink over time.
• Implantable cardioverter-defibrillator (ICD): For patients at high risk of sudden cardiac death, an ICD is a small device implanted under the skin that monitors heart rhythm and delivers an electric shock to restore a normal rhythm if a dangerous arrhythmia occurs.
• Lifestyle modifications: Depending on the severity of HCM, doctors may recommend avoiding high-intensity competitive sports, staying well hydrated and limiting alcohol and caffeine intake.

Living with HCM

A diagnosis of HCM does not mean you cannot live a full, active life. With proper medical management, most people with HCM can continue to work, exercise moderately and participate in daily activities. Key strategies for living well with HCM include:

• Regular follow-up appointments: Ongoing monitoring with your cardiologist helps track changes in heart thickness, function and rhythm over time.
• Staying physically active safely: While competitive high-intensity sports may be restricted, moderate exercise such as walking, swimming and light cycling is typically encouraged. Always discuss your exercise plan with your cardiologist.
• Managing stress: Chronic stress can elevate heart rate and blood pressure, potentially worsening symptoms. Techniques like deep breathing, meditation and adequate sleep can support heart health.
• Screening family members: Because HCM is genetic, first-degree relatives should undergo echocardiography and possibly genetic testing. Early detection in family members can prevent complications.
• Carrying medical identification: Wearing a medical alert bracelet or keeping a card in your wallet that notes your HCM diagnosis can be critical in emergency situations.

When to See a Cardiologist

You should seek evaluation from a cardiologist if you experience any of the following:

• Unexplained chest pain, especially during or after physical activity
• Episodes of fainting or near-fainting
• A family history of HCM, sudden cardiac death or unexplained heart failure at a young age
• Heart palpitations that are frequent, prolonged or associated with dizziness
• Shortness of breath that is disproportionate to your level of exertion

Early detection of HCM is key. When we identify it sooner, we can help patients stay active, protect their heart health and prevent serious complications. No one should ignore symptoms or family history — getting checked can make all the difference. Screening usually involves a special heart test like an echocardiogram or an EKG that will be ordered by your doctor.

HCM is common, genetic and often overlooked — but early detection can be life-changing. If you are concerned about symptoms or your family history, don’t wait to talk to your doctor about getting tested. With proper diagnosis and management, people with HCM can lead long, healthy and fulfilling lives.