What causes hypertrophic cardiomyopathy (HCM) and how to treat it

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Sometimes, HCM causes no symptoms. Due to this, many people do not receive a diagnosis of HCM until adolescence or adulthood, despite having had the condition since birth.

However, in people who do experience symptoms, HCM can cause:

• chest pain, especially during or after physical exertion
• shortness of breath, especially during or after physical exertion
• extreme tiredness
• changes in heart rhythms
• dizziness
• lightheadedness
• fainting
• swelling in the feet, ankles, legs, or abdomen, known as edema

Learn about different types of edema here.

The American Heart Association (AHA) states that HCM is a chronic condition that can worsen over time. This means that the symptoms may become more apparent as time goes on, and people may notice that it starts to have a more significant effect on their day-to-day life.

Anyone who experiences new or worsening symptoms should discuss them with a doctor, who can help them find ways to manage the condition.

Learn what heart failure can look like in a child.

HCM is congenital, which means that it is present at birth. The condition is heritable, and a person with a biological parent with HCM has a 50% chance of inheriting the risk of developing the condition.

HCM is due to changes in genes. The genes most commonly involved in the development of HCM are:

• MYH7
• MYBPC3
• TNNT2
• TNNI3

These genes have important roles in making up key structures of the heart muscle known as sarcomeres. Some of these genes are also important for muscle contractions and relaxations.

Experts are not yet completely sure why mutations in these genes lead to a buildup of the heart muscle wall.

Learn what heart failure can feel like.

As genetics are key to the development of HCM, a person cannot take steps to reduce their risk.

Most of the time, a person with HCM has one biological parent with the condition.

However, in rare cases, both copies of the gene are altered, which can lead to more severe symptoms.

According to the AHA, people with HCM have an increased risk of experiencing certain conditions. These include:

• atrial fibrillation, which can lead to:
  • blood clots
  • stroke
  • other heart-related complications
• heart failure
• sudden cardiac arrest, although this is rare

The British Heart Foundation also states that people with HCM may have an increased risk of developing endocarditis, which is an infection of the inner lining of the heart.

Experts emphasize the importance of an early diagnosis to minimize the risks of these complications.

Learn more about congenital heart disease.

Healthcare professionals may use a variety of tests to confirm a diagnosis of HCM, including:

• EKG: This test registers the electrical activity of the heart.
• Echocardiogram: This scan allows clinicians to see the structure of the heart and how it is pumping.
• Exercise test: A person will use a treadmill or exercise bike while undergoing an EKG recording. This shows clinicians how the heart works during physical activity.
• MRI scan: This scan provides detailed images of a person’s heart.

A person can also undergo genetic testing for HCM. This will involve providing a saliva sample or having a blood test.

Currently, the Food and Drug Administration (FDA) has approved only one medication for the treatment of HCM. The medication, called mavacamten (Camzyos), received approval in 2022 to treat people with obstructive HCM.

In people who do not yet have symptoms

Doctors will encourage people who have a diagnosis of HCM but are not yet experiencing symptoms to follow a heart-healthy lifestyle. This can involve:

• staying active
• eating a heart-healthy diet
• maintaining a moderate weight
• getting good quality sleep
• avoiding tobacco products

Doctors will also monitor a person for other conditions that may be complications of HCM.

Learn about following a cardiac diet.

In people who are experiencing symptoms

Doctors may recommend medications, surgery, or a combination of both for people with HCM who require management of their symptoms.

Medications

Medications that can help a person manage the symptoms of HCM include:

• beta-blockers
• calcium channel blockers
• antiarrhythmics
• diuretics

Although these may provide temporary relief of symptoms, they will not treat the HCM itself. They may also cause side effects. It is important to work with a doctor to determine the best treatment regimen.

Procedures

Surgical procedures that a doctor may recommend for people with HCM include:

• Septal myectomy: A surgeon removes part of the thickened septum that encroaches into the left ventricle to help improve blood flow.
• Alcohol septal ablation: In this nonsurgical procedure, doctors inject ethanol, a type of alcohol, into the small artery that provides blood to the thickened heart muscle. The alcohol destroys these cells.
• Cardiac implantable electronic devices (CIEDs): Doctors may recommend CIEDs such as implantable cardioverter defibrillators, pacemakers, or cardiac resynchronization therapy devices to help maintain a typical heart rhythm.
• Heart transplant: If a person has advanced, end stage HCM, doctors may suggest a heart transplant with a donor’s heart.

Learn about cardiac ablation surgery.

Many people with HCM experience few or no symptoms, and their life expectancy is the same as it is for those without the condition. Only in rare cases will the condition produce severe symptoms and complications. However, such severe complications may affect a person’s life expectancy.

For example, a person with HCM has an increased risk of developing abnormal heart rhythms or other heart problems. In very rare cases, these can be fatal.

However, by seeking medical attention as early as possible and then working with a doctor to find the most effective treatment plan, it is generally possible to live a full and active life.

A person should always contact a doctor if they notice changes in their heart rhythm or cardiac symptoms that concern them. Symptoms to be aware of include:

• shortness of breath
• chest pain
• rapid or irregular heartbeats
• lightheadedness
• fainting

Although these are symptoms of HCM, they may also be the result of other conditions. It is important to consult a doctor to receive an accurate diagnosis and an effective treatment plan.

If HCM does cause symptoms, a person may find that the condition affects the following areas of their life:

• Work: A person may need to discuss their condition with a doctor and their employer if their role is physically strenuous. However, most people find that it does not affect their work.
• Driving: Most people with HCM can drive as usual, but if a person experiences fainting or dizziness, they will need to notify the driving authorities.
• Exercise: It is best to discuss an exercise plan with a doctor. If a person notices their symptoms worsening during exercise, they should stop immediately. A doctor can recommend alternative, less strenuous forms of exercise.
• Diet and drinking: A person should follow a heart-healthy diet and ask a doctor for specific advice regarding food and alcohol. In some cases, they may suggest limiting the intake of alcohol.
• Sex: It is safe for people with HCM to have sex. However, if this activity feels too strenuous or causes symptoms, it is advisable to stop immediately.

People should never stop taking medications without speaking with a doctor.

A person cannot prevent HCM, as it is an inherited condition. However, they can help prevent complications of the condition by working with a doctor to find the right treatment plan for them.

Hypertrophic cardiomyopathy occurs when genetic changes inherited from biological parents cause the heart muscle to become excessively thick. This can make it more difficult for the heart to pump blood effectively.

Some people with HCM experience no symptoms at all. Others develop symptoms over time. These can include palpitations, fainting, and chest pain.

The treatment options for HCM include medications, surgery, and lifestyle changes.