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

Causes

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.

Symptoms

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

Diagnosis

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:

Stress test
Heart monitor

Treatment

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:

Remove the thickened portion of heart muscle
Repair or replace a damaged valve
Insert an implantable cardioverter defibrillators to help pace the heart

Prevention

There are no known guidelines to prevent this health problem.

RESOURCES:

American Heart Association
http://www.heart.org

National Heart, Lung, and Blood Institute
http://www.nhlbi.nih.gov

CANADIAN RESOURCES:

Canadian Cardiovascular Society
http://www.ccs.ca

Heart and Stroke Foundation of Canada
http://www.heartandstroke.ca

References:

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:
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Accessed March 9, 2021.

Hypertrophic cardiomyopathy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypertrophic-cardiomyopathy. Accessed March 9, 2021.

Pediatric cardiomyopathies. The American Heart Association website. Available at:
...(Click grey area to select URL)
Accessed March 9, 2021.

Last reviewed December 2020 by EBSCO Medical Review Board Kari Kassir, MD
Last Updated: 3/9/2021

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