Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is a heart condition where the muscle walls of the heart become thicker than normal. This can make it harder for the heart to relax and pump blood and may cause symptoms like chest pain, shortness of breath or irregular heartbeats. It’s genetic, meaning it runs in families. Some people have no symptoms, while others may need treatment to manage the condition.

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Comprehensive care for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease where the heart muscle becomes abnormally thick, making it harder for the heart to relax and pump blood. About 1 in every 200 to 500 people have it and HCM can affect anyone, regardless of age, culture, race, ethnic group or gender. It often starts during puberty, but symptoms can appear or worsen at any age, typically in midlife. Some people may experience symptoms like shortness of breath, chest pain or fainting, while others may have no symptoms at all.

At Tufts Medicine, our expert team treats all types of HCM with compassion and expertise. HCM is manageable with the right care. We work with you to create a personalized care plan that fits your needs and lifestyle.

A Tufts Medical Center echocardiogram technologist explains the screen to Hypertrophic Cardiomyopathy Center (HCM) patient.

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Conditions

Hypertrophic cardiomyopathy (HCM) most commonly affects the septum, the muscular wall separating the left and right ventricles. The type of HCM you have — obstructive or nonobstructive — depends on whether the thickened muscle blocks or limits blood flow from the heart.

Obstructive HCM: About 2 out of 3 people with HCM have this type. In obstructive HCM, blood flow from the heart is partly blocked because the thickened heart muscle and the elongated mitral valve block blood flow. For some people, the blockage happens during exercise, while for others, it can happen even at rest. This blockage increases pressure in the heart and causes symptoms.
Nonobstructive HCM: About 1 in 3 people with HCM have this type. The heart muscle is still thickened, but there’s no blockage to blood flow.

HCM can also lead to other heart conditions like atrial fibrillation (AFib), heart failure and stroke. About 1 in 4 or 5 people with HCM develop AFib, which is a rapid and irregular heartbeat that increases the risk of stroke because blood clots can form and travel to the brain.

With the right care, HCM is manageable. At Tufts Medicine, our expert team provides personalized treatment to help you live your best life.

HCM symptoms

Not everyone with hypertrophic cardiomyopathy (HCM) has symptoms, and the severity can vary from person to person. When symptoms do appear, they may include:

Arrhythmia (irregular heartbeats)
Chest pain or pressure
Fatigue or excessive tiredness
Lightheadedness, dizziness or fainting
Loss of consciousness
Palpitations (sudden, forceful heartbeats)
Shortness of breath

If you notice any of these symptoms, it’s important to talk to your doctor right away. Early diagnosis and treatment can make a big difference in managing HCM.

Atrial fibrillation in HCM

About 1 in 4 or 5 people with HCM experience atrial fibrillation (AFib), an irregular and often rapid heartbeat.

AFib can affect your health in 2 major ways:

Frequent AFib episodes can lower your quality of life, causing symptoms like fatigue, shortness of breath and palpitations.
AFib increases the risk of stroke because it can lead to blood clots that travel to the brain.

Treatment options for AFib in HCM include antiarrhythmic medications to manage irregular heartbeat and a minimally invasive procedure called catheter ablation, which can help control AFib. To reduce the risk of stroke, doctors often prescribe blood thinners (anticoagulants), which are one of the most effective ways to prevent clots from forming.

If you have HCM and experience symptoms of AFib, talk to your doctor about the treatment options that are best for you.

Testing

Although HCM is a genetic condition, many people don’t realize they have it until symptoms appear later in life. Regular physical exams are key to detecting HCM early and reducing the risk of severe symptoms.

In addition to a physical exam, we use the following cardiac imaging and noninvasive tests to confirm an HCM diagnosis:

Cardiac MRI: This imaging test provides a high resolution of your heart muscle.
Echocardiogram + stress echocardiogram: These imaging tests provide detailed pictures of your heart to identify thickened heart muscle caused by HCM and assess how well your heart pumps blood, especially during physical activity.
Electrocardiogram (EKG): Measures your heart’s electrical activity.
Heart monitor: Wearing an ambulatory ECG monitor may be recommended. This small, wearable device checks your heart’s rhythm while you do your normal activities. It records your heartbeats over time to help doctors find any unusual patterns or problems. Your doctor may recommend wearing it for one day or a few weeks.

Genetic testing for HCM

Genetic testing can help identify mutations linked to HCM and provide a genetic diagnosis for you. If you have a positive HCM gene mutation, testing can help guide screening for your family members.

Family screening

HCM is inherited, with a 50% chance of passing it to children. Early screening helps reduce risks. If HCM runs in your family, talk to your doctor about:

Clinical evaluation: A full heart health checkup.
Electrocardiogram (EKG): Measures your heart’s electrical activity.
Genetic testing: A quick cheek swab to look for HCM-related mutations.
Heart imaging: Checking for thickened heart muscle.

Treatments

HCM is treatable, and most people won’t need surgery or major procedures. If you ever need advanced care, we’ll be here to answer your questions and support you every step of the way. Whether it's medication, minimally invasive procedures or more advanced treatments, we’ll work closely with you to find the best plan for your heart health. Our goal is to help you live a full and active life, with the right care and support tailored to your needs.

Medications

Many people with HCM successfully control their symptoms for years or even decades with medication alone. Some of the most commonly prescribed medications for HCM include:

Antiarrhythmic drugs: Help control irregular heartbeats.
Anticoagulants (blood thinners): Reduce blood clot risk, especially with arrhythmia or atrial fibrillation.
Beta blockers: Slow the heart rate and reduce symptoms like chest pain or palpitations.
Calcium channel blockers: Relax blood vessels and help manage symptoms.
Cardiac myosin inhibitors: A new FDA-approved medicine that helps the heart muscle work better in people with HCM.
Sodium channel blockers: Control obstructive HCM symptoms.

Heart failure caused by obstructive HCM can be permanently improved with medications like beta blockers, verapamil and disopyramide.

Minimally invasive procedures

When medications aren't enough to manage your symptoms, we may consider minimally invasive procedures, such as alcohol septal ablation or catheter ablation for recurrent AFib. These procedures may also be recommended for older adults who haven't responded well to medication.

Alcohol septal ablation

Alcohol septal ablation is a procedure that helps reduce the thickness of the heart muscle and improve blood flow. It’s a good alternative to open-heart surgery, with fewer risks and complications.

Here’s how it works: A small tube (catheter) is placed into a blood vessel in your leg and guided to your heart. A small amount of alcohol is carefully injected into a targeted area of the heart muscle to reduce the thickness and improve blood flow.

Catheter ablation for recurrent atrial fibrillation (AFib)

Catheter ablation is a procedure that helps reset your heart’s rhythm if you have atrial fibrillation (AFib).

Doctors use a thin tube (catheter) to reach your heart through a small incision. The procedure takes about 2 hours, and you will be asleep the whole time under general anesthesia. Tiny scars are made in targeted areas of your heart to block the signals that cause the irregular rhythm. This helps your heart beat more steadily.

Advanced interventions

While most people with HCM won’t need major surgery, some may need more advanced treatment to restore healthy heart function. When medications and other less invasive procedures don’t work, we may recommend one of the following interventions to help manage symptoms and improve your quality of life:

Heart transplant

If you have nonobstructive HCM and severe symptoms, we’ll first try treating you with medications. If they don’t work, a heart transplant may be considered. Survival rates with a heart transplant are high, with about 90% of people surviving for 5–10 years.

Implantable cardioverter defibrillator

A small number of people with HCM are at higher risk for life-threatening arrhythmias (heart rhythm problems). To prevent this, we can insert a device called an ICD (implantable cardioverter defibrillator) into the chest. The ICD sends electrical pulses to the heart to restore a healthy rhythm and prevent sudden cardiac arrest and saves lives.

Septal myectomy

A septal myectomy is an open-heart surgery that helps clear the obstruction in your heart, improve blood flow and reduce your HCM symptoms.

During the procedure, the doctor removes the extra amount of muscle from the top of your septum wall. This helps restore your blood flow.

FAQs

How did I get HCM? Did I do something wrong to cause it?

Hypertrophic cardiomyopathy is a genetic heart disorder that is inherited from your parent. Your heart muscle did not thicken due to poor lifestyle habits or anything else you may have done to yourself over the years. However, although you did nothing to cause it, maintaining a healthy lifestyle through weight and diet will absolutely benefit you in the long run with respect to your symptoms and overall energy levels.

What is my life expectancy with HCM?

Most patients with hypertrophic cardiomyopathy can maintain an active lifestyle and have a normal lifespan. Mortality rates for HCM alone are only about 0.5% per year—which is no different than the general population for all causes. Most patients have near-normal life expectancies and live highly satisfying and productive lives.

Obstructive HCM sounds bad, should I worry?

Not everyone with obstructive hypertrophic cardiomyopathy (HCM) has symptoms. Many people live their whole lives without any problems from it.

For others, obstruction can lead to symptoms like shortness of breath, chest pain or feeling dizzy, especially during activity. This happens when the thickened heart muscle blocks blood flow out of the heart and increases pressure.

If you notice symptoms, it’s important to see a cardiologist who understands HCM. Treatments like septal myectomy or alcohol septal ablation can help reduce the blockage and improve how you feel.

My doctor recommends I get a septal myectomy. Will my heart muscle grow back?

Usually not. Heart muscle cells do not regenerate and will not grow back after an adequate surgery.

Can I exercise with HCM?

Yes, a regular exercise routine has many psychological and physical benefits. Having HCM does not make you immune to developing coronary artery disease or having a heart attack (or other diseases related to leading a sedentary lifestyle). Exercise counseling should be individualized. Remember to talk to your doctor before starting any exercise program.

Which HCM signs should I notify my doctor about right away?

It is very important to call a doctor if you have persistent palpitations—heart flutters—that do not resolve with rest or if you have extreme lightheadedness or instances of fainting (syncope). Please also contact a doctor if your symptoms change or worsen despite rest. This could include increased shortness of breath, new chest discomfort, worsening fatigue or fluid retention. We're always here for you, so don't hesitate to reach out.