Understanding Hypertrophic Cardiomyopathy (HCM)

Many people with HCM don’t experience any symptoms, according to the American Heart Association (AHA). Others may only feel symptoms during physical activity, such as exercising.

Symptoms of HCM may include:

• shortness of breath
• chest pain
• fatigue
• heart palpitations
• fluttering heart rate
• high blood pressure
• fainting
• dizziness
• edema

In some cases, HCM may cause severe symptoms like heart attack.

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There are two types of HCM, according to the AHA:

• Obstructive: This is the most common type of HCM. It refers to when the affected part of your heart muscle, typically the septum between the left and right ventricles, obstructs or reduces blood flow from the left ventricle to the rest of your body.
• Non-obstructive: This is when your heart muscle has thickened but does not impair blood flow.

The most common cause of HCM is genetics, which means you can inherit it from someone in your family.

Mutated genes may cause your heart muscle to thicken. Researchers have identified mutations in more than 15 genes that may cause HCM.

HCM follows a dominant pattern of inheritance, which means you may experience symptoms if you inherit one gene associated with the condition. However, inheriting the gene doesn’t necessarily mean you’ll have symptomatic disease.

Speak with a healthcare professional if you have a family history of HCM. Genetic testing may help identify whether you’re carrying an HCM gene mutation or if you’re likely to pass on the condition to another generation.

Another possible risk factor for HCM is high blood pressure, especially during exercise.

HCM affects the heart in several different ways, including:

• Septal hypertrophy: This is the thickening of your heart’s walls, which means your heart needs more force to pump.
• Mitral leaflet abnormalities: These are changes to the four flaps that close your mitral valve to keep blood moving forward in your heart.
• Mitral regurgitation: This generally occurs as a result of a suction effect, known as the Venturi effect. This may cause blood to backflow into your heart.
• Arrhythmia: An irregular or fluttering heart rate is a common side effect of HCM.
• Relaxation abnormalities: Thickening of your heart muscle that occurs along with HCM can cause a sluggish or irregular heart rate.

Imaging tests are the hallmark of diagnosing HCM. A healthcare professional may perform a range of tests to help measure several things, such as:

• heart muscle thickness and hypertrophy
• mitral regurgitation
• heart movements and rates
• the amount of blood your heart is pumping out

Some of these tests may include:

• physical examination
• echocardiogram
• electrocardiogram
• Holter monitor
• cardiac MRI
• cardiac catheterization

Sometimes, you may receive a diagnosis during an imaging test for something else and a doctor notices an atypical characteristic.

There’s currently no cure for HCM. Treatment for HCM focuses on relieving symptoms and preventing complications, especially sudden cardiac arrest.

Your treatment plan may depend on several factors, such as:

• symptoms
• age
• activity level
• heart function
• outflow obstruction

Medications

Medications are the first-line treatments for HCM. A healthcare professional may prescribe:

• beta-blockers
• calcium channel blockers
• antiarrhythmic medications
• diuretics

Recent research in HCM suggests that a drug called mavacamten (MyoKardia) may help reduce symptoms and improve physical functioning in people with symptomatic cardiomyopathy. The medication works by inhibiting cardiac myosin, a protein in your heart involved in contraction (squeezing).

Non-pharmacological treatments

A healthcare professional may recommend non-pharmacological treatments as part of your HCM treatment plan. These may include:

• septal myectomy
• pacemaker
• implantable cardioverter defibrillator (ICD)
• septal ablation, which involves an alcohol injection to destroy part of your thickened heart muscle

Lifestyle changes

A doctor may recommend the following lifestyle changes for HCM to reduce your risk of complications:

• eating a well-balanced diet
• keeping your weight at a healthy-for-you level
• doing low intensity physical activities
• stopping smoking, if you smoke
• limiting alcohol intake, as alcohol can cause atypical heart rhythms
• restricting high impact exercise and focusing on low impact activities, such as walking, golfing, or bowling

In many cases, HCM may never lead to serious health problems.

However, HCM may cause sudden cardiac arrest in some people. This occurs when your heart suddenly stops working and is also called “sudden cardiac death.”

According to the AHA, this typically happens when the electrical systems in your heart aren’t functioning properly, causing ventricular tachycardia or ventricular fibrillation.

Without emergency treatment, sudden cardiac arrest can be fatal.

HCM is the leading cause of sudden cardiac death in young athletes. This could manifest in an athlete with undiagnosed HCM who experiences sudden cardiac death on the playing field.

HCM may also lead to heart failure, which happens when your heart doesn’t pump the amount of blood your body needs.

What is the life expectancy of a person with hypertrophic cardiomyopathy?

The life expectancy for someone with HCM has dramatically improved. As little as 35 years ago, the mortality rates for HCM were 6% per year. In 2018, these rates were estimated at 0.5% per year.

Is hypertrophic cardiomyopathy serious?

Many people don’t experience symptoms of HCM or a treatment plan could help them live a normal life. However, HCM may lead to several severe complications, such as sudden cardiac arrest.

At what age does hypertrophic cardiomyopathy develop?

HCM may develop at any point in your life, but most people receive a diagnosis between ages 30–50 years, according to the AHA.

What should you not do with hypertrophic cardiomyopathy?

A healthcare professional may recommend certain lifestyle changes if you receive a diagnosis of HCM. These may include stopping smoking if you smoke, doing light-intensity physical activity, eating a well-balanced diet, and limiting alcohol, among others.

HCM is a genetic, lifelong disease. In some people, it can contribute to early death or impact their quality of life.

New treatments and medications may potentially extend the life and daily functioning of those with symptomatic HCM.