Hypertrophic Cardiomyopathy

What Is Hypertrophic Cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is a thickening of part of the heart muscle. As the heart muscle thickens, it also becomes stiffer. In some cases the thicker muscle blocks part of the blood flow out of the heart. As a result, HCM can cause fast arrhythmias (abnormal heart rhythms) and sudden cardiac death.
Illustrations of hearts showing a normal and a hypertrophic cardiomyopathy heart

In most cases, HCM is inherited from parents or caused by a problem that developed with a gene before birth. In either situation, people with HCM can pass the gene for HCM on to their children. In other cases, HCM can be caused by high blood pressure or aging.

Symptoms of HCM vary, but can include chest pain, dizziness, or passing out.

People of any age can have hypertrophic cardiomyopathy. For young people, unfortunately, HCM often causes sudden cardiac death before they even know they have HCM. In fact, hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in people under age 30.1

If you have a family member with HCM, sudden cardiac death can be a serious risk. Talk to your doctor about being tested.

How Is HCM Treated?

Often people with HCM have mild symptoms, and many can expect to have a normal lifespan. But patients usually receive treatments if they have symptoms or are at risk of sudden cardiac death. Treatments include the following:

  • Medications — Your doctor may order a beta blocker to help decrease your heart's stiffness.
  • Surgery — Some patients may have surgery to remove part of the thickened heart muscle.
  • Cardiac devices — People at high risk of sudden cardiac death might receive an implantable cardioverter defibrillator. The defibrillator is designed to stop a dangerous arrhythmia before it causes sudden cardiac death.