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Hypertrophic Cardiomyopathy—Child

(Cardiomyopathy, Hypertrophic—Child; HCM—Child; Idiopathic Hypertrophic Subaortic Stenosis—Child; Asymmetric Septal Hypertrophy—Child; ASH—Child; HOCM—Child; Hypertrophic Obstructive Cardiomyopathy—Child)

How to Say It: hi-per-TRO-fik car-DEE-o-my-AH-pah-thee


Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy. This is when the heart muscle thickens due to genetic problems with the muscle’s structure. As the muscle thickens, it must work harder to pump blood. This strains the heart muscle. Sometimes, the thickened muscle gets in the way of the blood leaving the heart and causes a blockage. This blockage can cause a nearby valve to become leaky. HCM can cause uneven muscle growth. This can cause the heart to pump in a disorganized way. Rarely, it can cause abnormal heart rhythms that can be deadly.

Normal Heart and Heart With Hypertrophic Cardiomyopathy
Hypertrophic Cardiomyopathy

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HCM may be caused by a gene that causes an abnormality in the heart muscle. It can be inherited or it can happen from changes in the genes over time.

Risk Factors

The risk of this problem is higher in children who have a family member with HCM.


Some children may not have any symptoms. Others may have:

  • Chest pain
  • Fainting, particularly during exercise
  • Lightheadedness, particularly following exercise
  • Rapid heartbeat
  • Problems breathing, such as shortness of breath
  • Lack of energy
  • Tiring easily during exercise or activity

Problems in babies may be:

  • Fast, heavy breathing when feeding
  • Sweating when feeding
  • Tiredness or lack of activity
  • Poor weight gain


The doctor will ask about your child’s symptoms and health history. A physical exam will be done. It will focus on the heart.

Blood tests will be done.

Images may be taken. This can be done with:

Your child's heart activity will be tested. This can be done with:


The goal of treatment is to manage symptoms and prevent damage. Medicine may be given to:

  • Maintain normal heart function
  • Remove excess fluid from the body

Children who are not helped by these methods may need surgery to:


There are no known guidelines to prevent this health problem.


American Heart Association

National Heart, Lung, and Blood Institute


Canadian Cardiovascular Society

Heart and Stroke Foundation of Canada


Elliott PM, Anastasakis A, et al. 2014 ESC Guidelines on diagnosis and management of hypertrophic cardiomyopathy: The Task Force for the Diagnosis and Management of Hypertrophic Cardiomyopathy of the European Society of Cardiology (ESC). Eur Heart J. 2014 Oct 14;35(39):2733-2779.

Hypertrophic cardiomyopathy. Cleveland Clinic website. Available at: Accessed March 9, 2021.

Hypertrophic cardiomyopathy. EBSCO DynaMed website. Available at: Accessed March 9, 2021.

Pediatric cardiomyopathies. The American Heart Association website. Available at: Accessed March 9, 2021.

Last reviewed December 2020 by EBSCO Medical Review Board Kari Kassir, MD