What Is Hypertrophic Cardiomyopathy (HCM)?

There are two main types of hypertrophic cardiomyopathy. Both can impact how the heart pumps blood throughout the body.

• Obstructive Two-thirds of people who have HCM have obstructive HCM. This occurs when the wall (septum) between the heart’s bottom two ventricles thickens and stiffens, blocking or seriously reducing blood flow out of the left ventricle to the body.
• Nonobstructive: In about one-third of people with the disease, HCM is nonobstructive, meaning the heart muscle becomes thick and stiff but doesn’t block blood flow out of the heart. But the amount of blood the heart can pump into the body may be reduced.

Many people living with hypertrophic cardiomyopathy don’t experience any symptoms. Some will never learn that they have the condition, and will never experience any obvious downsides.

• Chest pain
• Shortness of breath
• Abnormal heart rhythms (arrhythmia) or palpitations
• Rapid heart beat
• Fatigue or lack of energy
• Dizziness or lightheadedness
• Fainting
• Heart murmur
• Swelling in the ankles, feet, legs or neck veins

Some may only experience these symptoms when they’re exercising or physically exerting themselves.

These symptoms are not unique to HCM, and can be caused by many other cardiovascular conditions, some of which are more dangerous than HCM, such as heart failure and atrial fibrillation. People experiencing any of these symptoms should see a healthcare provider for evaluation.

If you are experiencing symptoms of heart disease, a provider may start with a physical exam, listening to your heart for any sign of a heart murmur. If the provider hears the whooshing sound that could indicate the heart is having trouble pumping blood normally, they will likely move on to diagnostic tests.

Identifying HCM can require a number of tests, but typically begins with an echocardiogram, or “echo.” The noninvasive test uses sound waves to create images of the heart that can show how thick the heart muscle is. Other options to help confirm an HCM diagnosis include:

• Electrocardiogram (ECG), a test that checks the heart’s electrical signals and rhythm
• A Holter monitor, an ECG that is worn for a day or more
• Magnetic resonance imaging (MRI), another way for doctors to see the heart
• Stress tests, which assess the heart’s performance during exercise
• A family history analysis

Cardiologists have a number of options to treat HCM, including medications, surgery, and implantable devices. These treatments are designed to reduce the long-term risk of cardiovascular disease and to alleviate symptoms and improve quality of life.

Medication Options

• Beta-blockers to lower blood pressure and heart rate
• Calcium channel blockers to help blood vessels relax
• Diuretics to help the body remove excess water and sodium

If you have complications of the disease, such as arrhythmia, you may need medications to treat those conditions specifically. These may include:

• Antiarrhythmic drugs to treat abnormal heart rhythms, such as amiodarone (Pacerone) or disopyramide (Norpace)
• Blood thinners, which can prevent blood clots in people with HCM and atrial fibrillation

Surgery Options

Some people may need surgery to treat HCM:

• Septal Myectomy is an open-heart surgery that removes parts of thickened heart tissue between the walls of the heart chambers. This surgery is considered safe and its benefits are long-lasting.

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• Septal Ablation is a less-invasive treatment in which a doctor guides a catheter through a blood vessel and into the heart, spraying alcohol onto thickened heart tissue. The alcohol causes some of the muscle to shrink and die, improving blood flow.

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A variety of other surgeries may be appropriate, especially for people who experience other heart conditions in addition to HCM.

Implanted Devices

• An implantable cardioverter-defibrillator (ICD) is a device implanted in the chest or near the armpit that detects potentially fatal arrhythmias. In the event of a disrupted heart rhythm, the device sends an electrical shock to the heart, causing it to beat regularly again.
• A pacemaker is a battery-operated device implanted near the collarbone that uses electrical signals to regulate your heartbeat.

There is no known way to prevent HCM.

Visit a cardiologist regularly, even if you don’t have any HCM symptoms. This is the best way to preserve your long-term heart health.

People with HCM may be cautioned against certain types of exercise. Though physical activity remains important for good health, your doctor may warn you against athletic exertion that requires straining or short bursts of activity.

• Staying well hydrated
• Avoiding extreme cold or heat (including saunas and hot tubs)
• Reducing stress

Hypertrophic cardiomyopathy is a chronic, life-long condition.

Many people living with the disease don’t know they have it and live normal lives. HCM does not necessarily have an effect on life expectancy, even when it requires drugs, an implanted device, or surgery.

Though HCM can be benign on its own, it often occurs with other cardiovascular conditions.

Data on racial disparities in HCM are sparse, but some studies have suggested that people from different racial and ethnic backgrounds have different levels of risk due to the condition:

• Black Americans with HCM may have more severe symptoms and outcomes than white Americans, although it is difficult to know if the difference is due to genetic factors or to inequities in healthcare access and delivery.

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• People of Hispanic or Latino descent with HCM may have an enhanced risk of serious heart failure.

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Hypertrophic Cardiomyopathy Association 

The Hypertrophic Cardiomyopathy Association has online patient discussion groups that can make it easy for people living with HCM to connect with others who have the disease and learn more about it. The organization also sponsors volunteer opportunities and advocacy events.

The Takeaway

• Hypertrophic cardiomyopathy (HCM) affects about 1 in 500 people, and many living with the disease do not know they have it.
• The symptoms of HCM (including shortness of breath, chest pain, and dizziness) overlap with many other conditions. Getting screened is important, especially for people with a family history of the condition.
• HCM is extremely treatable, and though some will require drugs, surgery, or an implantable device, many people with the condition do not experience a significant decline in life expectancy or quality of life.