Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a complex type of heart disease that thickens your heart muscle. “Hypertrophic” means something is bigger than it should be. “Cardiomyopathy” represents a group of conditions that affect your heart muscle.

The thickening HCM causes can affect any area of your heart’s muscle tissue (myocardium). But HCM most commonly affects the septum — the middle wall that divides your heart into two sides. This makes your heart’s left ventricle have less space to pump blood.

Hypertrophic cardiomyopathy affects about 1 in 500 people in the U.S. But many people don’t know they have it. It’s a lifelong condition that can get worse over time, leading to serious complications. The good news is that early diagnosis and treatment can help prevent complications. Lifestyle changes can also help you stay healthy.

Types of this condition

There are two main types of hypertrophic cardiomyopathy:

• Obstructive HCM. The thickened part of your heart muscle is in the septal wall. This blocks or reduces blood flow from your left ventricle to your aorta.
• Nonobstructive HCM. Your heart muscle is thickened in other areas, like the bottom of your heart, right ventricle or entire left ventricle. This thickening doesn’t block blood flow out of your heart.

About 2 in 3 people with HCM have the obstructive type.

Symptoms of hypertrophic cardiomyopathy

Common symptoms of hypertrophic cardiomyopathy include:

• Chest pain — usually with physical activity
• Dizziness
• Shortness of breath and fatigue, especially with physical activity
• Fainting
• Feeling like your heart’s beating too fast or a fluttering in your chest (palpitations)
• Swelling (edema) in the lower part of your body or in neck veins

You may have several of these symptoms or none at all. If you have them, it’s crucial to see your healthcare provider.

Hypertrophic cardiomyopathy causes

Gene changes cause about 3 in 5 cases of hypertrophic cardiomyopathy. Healthcare providers call this familial HCM. The changes are to genes that are responsible for controlling heart muscle growth. Familial HCM has an autosomal dominant inheritance. This means only one biological parent needs to have an altered gene to pass it on.

Many gene changes can cause hypertrophic cardiomyopathy. Because of this, the severity of HCM can vary widely — even within the same biological family. Some people who have the changed gene may never develop the disease.

Up to 2 in 5 cases of HCM have no known cause. These cases don’t have a gene change that explains the condition. Researchers are currently studying other possible causes of HCM.

HCM can develop at any age. But most people with the condition receive a diagnosis around 40 years of age.

Complications of this condition

Complications of HCM can include:

• Atrial fibrillation (Afib), which can lead to blood clots and stroke
• Congestive heart failure
• Infective endocarditis
• Ventricular arrhythmias
• Sudden cardiac arrest and death

Most people with hypertrophic cardiomyopathy don’t experience complications. But because HCM can cause life-threatening health issues, it’s essential to see your cardiologist regularly if you have the condition. It’s also important to get screened for HCM if you have a family history of it.

How doctors diagnose this condition

Healthcare providers can typically diagnose hypertrophic cardiomyopathy based on the following:

• Medical history: Your healthcare provider will ask about your symptoms and family history, like a history of heart disease or sudden death.
• Physical exam: Your provider will listen to your heart and lungs with a stethoscope. If you have hypertrophic obstructive cardiomyopathy (HOCM), they may hear a heart murmur.
• Tests: Providers most often start with an electrocardiogram (ECG/EKG), which usually shows abnormal results with HCM. They’ll then likely recommend an echocardiogram to diagnose HCM. It can show the thickening of your heart walls.

Your provider may recommend other tests to help confirm the diagnosis and check for complications. These tests include:

• Blood tests
• Cardiac catheterization
• Cardiac MRI
• Holter monitor and/or cardiac event monitor
• Exercise stress echo test
• Genetic testing

Your provider will also recommend that your first-degree biological family members (parents, siblings and children) get screened for HCM.

How is hypertrophic cardiomyopathy treated?

Together, you and your cardiologist will decide on a treatment plan based on how HCM is affecting you and your health.

The goal of treatment is to minimize or prevent symptoms and reduce the risk of complications. HCM treatment can include:

• Monitoring and lifestyle changes
• Medications
• Procedures

If possible, it’s best to receive care through a hospital system that’s experienced in treating hypertrophic cardiomyopathy.

Monitoring and lifestyle changes

Your cardiologist will assess your risk for complications. If your risk is low and you don’t have symptoms, they may recommend just monitoring your heart and health over time.

Regardless of your risk, your cardiologist will likely recommend a heart-healthy lifestyle. This includes:

• Avoiding or quitting smoking
• Eating heart-healthy foods
• Getting enough quality sleep
• Getting regular mild to moderate physical activity
• Maintaining a weight that’s healthy for you
• Managing other health conditions, like high blood pressure or diabetes

Medications

Medications that may help improve HCM symptoms include:

• Beta-blockers
• Calcium channel blockers
• Diuretics

A myosin inhibitor (mavacamten) can help improve symptoms and heart function in adults with obstructive HCM. This is the first medication that directly targets the underlying cause of HCM. The U.S. Food and Drug Administration (FDA) approved it in 2022.

Like all medications, these may have certain side effects. Your cardiologist will discuss the risks and benefits with you.

You may also need to take prophylactic (preventive) antibiotics for dental procedures to reduce the risk of bacterial endocarditis.

Procedures

Procedures that can help treat obstructive hypertrophic cardiomyopathy or prevent complications include:

• Septal myectomy: Your surgeon removes a small amount of your thickened septal wall. This widens the path your blood takes from your left ventricle to your aorta. It’s an open-heart surgery.
• Alcohol septal ablation: This is a minimally invasive procedure. A provider injects isopropyl alcohol into an artery that supplies blood to the area of thickened heart muscle. The alcohol kills the thickened tissue. This procedure is for people who can’t have a septal myectomy.
• Implantable cardioverter defibrillator (ICD): An ICD is a small device placed just under your skin that constantly monitors your heart rhythm. ICDs can help if you’re at risk for life-threatening arrhythmias or sudden cardiac death.

When should I see my healthcare provider?

You’ll need to see your cardiologist regularly so they can check on your heart’s health. HCM is a lifelong condition. They’ll let you know how often you’ll need follow-up appointments based on the severity of HCM and your treatment plan.

What can I expect if I have hypertrophic cardiomyopathy?

If you have HCM, you’ll want to do what you can to protect your heart and overall health. The prognosis (outlook) for HCM varies considerably based on:

• The age of onset
• The severity
• If you have symptoms and/or complications

Your cardiologist can give you a better idea of what to expect based on your unique situation. Lean on them for guidance and support.

What is the life expectancy of someone with hypertrophic cardiomyopathy?

For most people, HCM doesn’t limit their life expectancy. Years ago, mortality (death) rates for people with HCM were 1% to 4%. With treatment, these numbers are now closer to 0.5%.

Most people with HCM have a low risk for complications and an even lower risk for sudden cardiac death. But hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in athletes under age 35.

Can this be prevented?

There’s nothing you can do to prevent hypertrophic cardiomyopathy. But because HCM is often genetic, screening can help catch it early and prevent complications.

It’s important to have screening if you have a biological parent, sibling or child (first-degree relative) with the condition.

The first step is to have an electrocardiogram (EKG) and echocardiogram (echo) to check your heart. If the test results show signs of HCM, you’ll need to see a cardiologist.

It’s possible to have normal test results even if hypertrophic cardiomyopathy runs in your family. In this case, you should have a follow-up echo and EKG every three years until you’re 30 years old, and then every five years after that.

What medications should I avoid if I have hypertrophic cardiomyopathy?

Your cardiologist may tell you to avoid certain medications, like:

• Nitrates (because they lower blood pressure)
• Digoxin (because it increases the force of your heart’s contraction)