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 pump blood and may cause symptoms like chest pain, shortness of breath or irregular heartbeats. It’s usually genetic, meaning it can run in families. Some people have no symptoms while others may need treatment to manage the condition.
Helping get your heart back on beat
Hypertrophic cardiomyopathy (HCM) is a common genetic disease where the heart muscle becomes abnormally thick, making it harder for the heart to pump blood. About 1 in 500 people have it, which adds up to 750,000 Americans — more than Boston’s entire population.
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.
HCM is manageable with the right care. At Tufts Medicine, our expert team treats all types of HCM with compassion and expertise. We work with you to create a personalized care plan that fits your needs and lifestyle.
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Conditions
Hypertrophic cardiomyopathy (HCM) causes excessive thickening, or hypertrophy, of your heart muscle, making it challenging for the heart to pump blood to the rest of the body. It 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 presses on the mitral valve. 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 have this type. The heart muscle is still thickened, but there’s no blockage to blood flow. However, some people experience severe symptoms that aren’t fully controlled with medication, which can lead to heart failure over time.
HCM can also lead to other heart conditions like atrial fibrillation (AFib), heart failure and stroke. About 1 in 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 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 treatment options that are best for you.
Testing
Although HCM is a genetic condition present at birth, 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 + echocardiogram: These imaging tests provide detailed pictures of your heart to identify thickened heart muscle caused by HCM.
- Electrocardiogram (EKG) + stress echocardiogram: These tests measure your heart’s electrical activity and assess how well your heart pumps blood, especially during physical activity.
Family screening + genetic testing
Hypertrophic cardiomyopathy (HCM) is linked to several gene mutations, and genetic testing may help determine if you carry one. People with HCM have a 50% chance of passing the condition to their children, so family screening is highly recommended. Early detection through family screening and genetic testing can help prevent severe symptoms and manage risks. If you have a family history of HCM, talk to your doctor about getting screened. This could protect both your health and your loved ones. Screening typically includes:
- Cardiovascular imaging: Tests like echocardiograms or MRIs to check for heart muscle thickening.
- Clinical evaluation: A complete heart health assessment and related symptoms.
- Genetic testing (optional): A simple blood test to identify mutations linked to HCM.
While only 30% of people with HCM test positive for known mutations—since researchers are still discovering new ones—genetic testing can still provide valuable insights into your family’s risk, even if specific mutations are not detected.
Treatments
HCM is very treatable, and the majority of people won’t require major interventions like surgery. In the event that you need a more advanced procedure, we’ll be here to answer any questions and support you every step of the way.
Monitoring
An ambulatory ECG monitor is a small, wearable device that records your heart rhythm during normal day-to-day activities. It can be worn for various lengths of time ranging from 24 hours to several weeks.
We’ll use it to detect any abnormal rhythms of the upper and lower chambers of your heart and see if they align with any HCM symptoms, like dizziness, a fast heartbeat or loss of consciousness.
Medications
Many people with HCM successfully control their symptoms for years or even decades with medication alone. Some of our most commonly prescribed HCM medications include:
- Anticoagulants (blood thinners): These help manage arrhythmia and atrial fibrillation.
- Antiarrhythmic drugs: These also help manage arrhythmia and atrial fibrillation.
- Beta blockers: These help control additional symptoms.
- Calcium channel blockers: These help control symptoms.
- Disopyramide: These help control obstructive HCM symptoms.
Heart failure with obstructive HCM is permanently reversible with medications like beta-blockers, verapamil and disopyramide.
Minimally invasive procedures
When medications aren't helping your symptoms, we can explore minimally invasive procedures, like an alcohol septal ablation or catheter ablation for recurrent AFib, to treat HCM. We also may recommend minimally invasive procedures for older adults.
Alcohol septal ablation
An alcohol septal ablation is a minimally invasive procedure that helps alleviate symptoms and regulate blood flow by reducing the thickness of your ventricular septum. It’s a smart alternative to open-heart surgery because it leads to many of the same benefits with fewer risks and complications.
Alcohol septal ablations are oftentimes recommended for older people whose HCM symptoms don’t improve with medications.
For this procedure, we’ll place a flexible tube called a catheter into the femoral artery in your leg and then guide it up to the septal artery in your heart. When the catheter is in position, we’ll inflate a tiny balloon at the tip of the catheter. This lets us temporarily block your blood flow so we can release a small amount of alcohol into your septal artery.
The alcohol will reach the muscular walls in your septum and help reduce their thickness. It’ll take a couple of weeks for this procedure to have a full effect on your heart and blood flow.
Alcohol septal ablation is a surgical procedure to help with blood flow.
Catheter ablation for recurrent atrial fibrillation (AFib)
A catheter ablation for AFib is performed to reset your heart’s rhythm. This catheter-based treatment falls under the interventional cardiology medical specialty, where doctors can treat complex heart conditions using only a small incision.
A catheter ablation takes about 3–4 hours to complete, and you’ll be under general anesthesia. The procedure involves creating tiny scars on your heart that ultimately build tissue to help maintain a healthy heartbeat. The catheters can apply 2 different kinds of energy to create the scars:
- Cryo (freezing energy)
- Radiofrequency (heat energy)
After the procedure, most people return to their normal activities in a few weeks.
Potential interventions
While most people living with HCM won't require major surgery to get their condition under control, for those who do, our goal is to help restore healthy heart function.
Heart transplant
If you’re living with nonobstructive HCM and experiencing severe symptoms, we’ll first recommend treatment with medications. If these don’t work, we might recommend a heart transplant. The good news is that survival with a heart transplant is exceptional, with an estimated 90% survival at 5–10 years.
A heart transplant involves surgically replacing a failed heart with a healthy one. It’s a serious procedure that often involves time spent on a waitlist and a long recovery time. Hearing that you need a heart transplant is never easy, but we have resources and support available to help you process the news and stay strong.
Implantable cardioverte-defibrillator (ICD)
A small handful of people with HCM are at increased risk for life-threatening arrhythmias. We can get ahead of this risk by inserting a device called an ICD into the chest. To prevent sudden cardiac arrest, the ICD delivers electrical pulses to the heart to return it to a healthy rhythm.
In turn, this device can help you get back in the swing of things you love to do, for as long as you love doing them.
Septal myectomy
A septal myectomy is a type of open-heart surgery that allows us to clear the obstruction in your heart, create a healthy blood flow from your heart to the rest of your body and ultimately alleviate your HCM symptoms.
During a septal myectomy, the doctor makes a small incision in the aorta to remove a small amount of muscle from the top of your septum wall. By removing some of this extra muscle, we can help restore your heart’s healthy function.
The average hospital stay for this procedure is 5 days, and recovery will take several weeks.
Septal myectomy. Surgical procedure.
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