Understanding Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a type of heart disease in which the heart muscle becomes too thick. This can make it harder for the heart to pump blood. The thickened muscle can block blood flow and cause heart rhythm problems.^1,2

HCM can develop at any age, but it is most often diagnosed in middle age. Some people with HCM have no symptoms, which leads to many undiagnosed cases. Others have noticeable symptoms, especially when they exercise.^1,2

HCM can be life-threatening if left undiagnosed. In the United States, HCM is the most common cause of sudden cardiac death in young people and competitive athletes.²

What causes hypertrophic cardiomyopathy?

HCM is usually a genetic condition. It is thought to be caused by defects in the genes that control the growth of the heart muscle. These genetic changes make the heart muscle grow abnormally thick.^1,2

Many people with HCM inherit the condition from a parent. It is a lifelong condition, but symptoms may not appear until later in life.^1,2

Who is at risk?

People with a family history of HCM are at highest risk. If a parent has gene-related (also known as sarcomeric) HCM, their child has a 50 percent chance of inheriting the condition. Although having a family member with HCM increases the likelihood of developing HCM, the age at which symptoms appear and their severity can vary. About 40% of HCM develops in people with no known family history and without an identifiable genetic component. But these people tend to develop HCM later in life and it tends to be less severe.^3,4

If you have a parent, child, or sibling with HCM, you should get checked by your doctor. They will likely ask you about any other heart-related conditions that have occurred in your family, such as heart failure or cardiac arrest.^2,3

What are the symptoms of hypertrophic cardiomyopathy?

Symptoms can be different for each person. Some people have no symptoms. Others may notice signs that something is not right. Often, people do not know they have HCM until a doctor finds it during a routine checkup.^1-3

Symptoms of hypertrophic cardiomyopathy may include:^1-3

• Shortness of breath, especially during exercise
• Chest pain
• Dizziness or fainting
• Heart palpitations (fluttering or fast heartbeat)
• Fatigue
• Swelling in the legs or ankles

How is hypertrophic cardiomyopathy diagnosed?

Doctors use several tests to diagnose HCM. These tests help check the heart's structure and how well it works. Common tests to diagnose HCM include:^1,2,5

• Electrocardiogram (ECG or EKG) – This test measures the heart's electrical activity and can detect abnormal rhythms.
• Holter monitor – This portable device records the heart's activity over 24 to 48 hours to detect abnormal heart rhythms.
• Echocardiogram – This imaging test uses sound waves to create pictures of the heart and check for thickened heart muscle.
• Cardiac MRI – This scan provides detailed images of the heart and helps doctors assess the severity of the thickening.
• Stress test – This test checks how the heart responds to exercise. It helps evaluate symptoms like shortness of breath.
• Genetic testing – This test can identify gene changes linked to HCM, especially in people with a family history of the condition.

Other tests may be used to gain more information. Talk to your doctor about what diagnostic tests you may need.¹

How is hypertrophic cardiomyopathy treated?

There is no cure for HCM. But treatments can help manage symptoms. Your doctor will choose the best treatment based on your symptoms and heart condition. Treatment options can include:^1,2,4,6

• Medicines – Beta-blockers, heart rhythm medicines, and calcium channel blockers help slow the heart rate and improve blood flow.
• Surgery – If medicines do not help with symptoms, surgery may be the next step. Some people may need a procedure called a septal myectomy. This surgery removes part of the thickened heart muscle to improve blood flow.
• Septal ablation – This is a less invasive procedure that uses alcohol to shrink part of the thickened heart muscle.
• Implantable cardioverter defibrillator (ICD) – Having HCM increases the risk of irregular heartbeats. Some patients who have HCM may need an ICD. An ICD is a device placed in the chest to detect dangerous heart rhythms. When it detects an abnormal rhythm, it sends a low-energy shock to reset the rhythm.
• Permanent pacemaker –This is a device that helps the heart beat in a healthy rhythm. This is used in patients who experience severe enough cardiac events where the heart is no longer able to send electrical signals to beat properly.
• Lifestyle changes – Avoiding intense exercise and staying hydrated can help prevent symptoms. People with HCM should also eat a healthy diet, limit alcohol, and never smoke.

Can hypertrophic cardiomyopathy be prevented?

Since HCM is usually genetic, there is no known way to prevent it. However, early detection can help manage the condition and reduce complications.³

People with a family history of HCM should see a doctor for regular checkups. Genetic testing may help identify people at risk. Early detection and treatment can help prevent serious heart problems.^1,3