What Is Hypertrophic Cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) affects one in 500 people in the general population. In most cases, HCM is caused by genetic mutations.

Doctors usually discover HCM during cardiac testing (an electrocardiogram or echocardiogram). During this test, doctors see thickening (hypertrophy) on the heart’s left lower chamber (ventricle), even though the patient has no other disease that could cause this thickening.

Most patients with left ventricular hypertrophy have heart cells that are larger than normal. These larger cells cause the heart's lower chambers, usually the left chamber (ventricle), to become thick and stiff. But the location and amount of thickening can be very different for each person. Because of this, HCM can be hard to diagnose.

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Symptoms of HCM

Symptoms of HCM are different depending on how old you are. Most patients with HCM don’t have many symptoms. For this reason, a doctor may discover HCM during a routine appointment for other issues. Some patients with HCM have cardiac arrhythmias (irregular heartbeat), heart failure symptoms, or sudden cardiac death.

Early Stage Symptoms

In the early stages of HCM, you may experience any of the following:

  • Chest discomfort
  • Shortness of breath
  • Fatigue
  • Palpitations
  • Fainting or dizziness (particularly with exercise)

Over time, HCM can get worse and cause heart failure with symptoms of shortness of breath, chest discomfort, and edema. HCM can also cause atrial fibrillation, which increases your chances for stroke. In addition, HCM can cause sudden cardiac death because of ventricular arrhythmias (abnormal rapid heartbeats).

How Is Hypertrophic Cardiomyopathy Diagnosed?

View Image Figures A & B:
Figure A shows a normal patient's
heart; figure B shows a patient's
heart with hypertrophic
cardiomyopathy.

Doctors often diagnose HCM by using noninvasive cardiac imaging, including echocardiography and/or cardiac magnetic resonance imaging. To diagnose HCM, doctors will look at a patient’s left ventricle (lower heart chamber). If the patient’s left ventricle is hypertrophied or thickened (usually ≥15 mm wall thickness), and if the patient doesn’t have cardiac disease or another disease that causes ventricle thickening, the patient may have HCM.

Inherited Disorder

HCM is inherited in an autosomal dominant pattern. This means that people with HCM have a 50 percent chance of passing this condition on to their children. Genetic researchers have identified over 1,500 mutations affecting more than 15 genes associated with HCM.

HCM can also be identified through family history and molecular genetic testing. These tests accurately diagnose HCM in a patient. They can also identify if a patient’s relatives have the HCM mutation.

You can have genetic testing for HCM with a blood sample. The test is covered by most insurance policies.

Why Choose University of Utah Health?

Comprehensive, Expert Care for Treating HCM

HCMA seal logo

The Hypertrophic Cardiomyopathy (HCM) Program at University of Utah Health is the first in the state of Utah and one of the nation’s few comprehensive programs for evaluating and managing HCM. The program offers a comprehensive evaluation by experts in:

We understand that hypertrophic cardiomyopathy is a complex disease. By bringing doctors from multiple specialties together, we can provide leading-edge evaluation and a therapeutic plan that best suits your individual needs.

For more information email us at HCM@hsc.utah.edu. Call 801-585-5122 or

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