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Hypertrophic cardiomyopathy, or HCM, is a form of cardiomyopathy . This is a condition in which 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 fatal.

Normal Heart and Heart With 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.

Having a family member with HCM is a risk factor for your child.

Symptoms may include:

• Chest pain
• Fainting, particularly during exercise
• Dizziness or lightheadedness, particularly following exercise
• Heart palpitations
• Shortness of breath or difficulty breathing
• General fatigue
• Tiring easily during exercise or activity

These symptoms can be caused by some of the side effects of the condition, including abnormal heart beats . The blocked or reduced blood flow is usually the cause of symptoms like dizziness, fainting, and difficulty breathing. Babies with the condition may have the following symptoms:

•  Fast, heavy breathing when feeding
• Sweating when feeding
• Tiredness or inactivity
• Poor weight gain

Some children may not have any symptoms. The doctor may suspect your child has the condition if she has a murmur , although not every person with HCM has a murmur and not all murmurs are due to HCM.

The doctor will ask about your child’s symptoms and medical history and do a physical exam. Tests may include the following:

• Stress test —tests how the body responds to exercise, which can help in detecting heart and lung problems
• Echocardiography —uses sound waves (ultrasound) to examine the size, shape, and motion of the heart
• Transesophageal echocardiogram —images of the heart are taken using sound waves with a sound wave transducer being put down the throat
• Heart monitor—a portable electrocardiogram (ECG) records continuous heart activity, usually over a 24-72 hour period, to determine regularity of the heartbeat
• Heart catheter —a catheter is inserted into an artery in the groin area and threaded to the heart chambers (An x-ray machine shows real-time images of the body as a dye is injected through the catheter. This allows angiograms (photos) to be taken of the blood vessels and the heart.)
• Chest x-ray —uses radiation to take a picture of structures inside the body
• Blood tests

Treatment focuses on controlling symptoms and preventing complications. Talk with the doctor about the best treatment plan for your child. Treatment options include:

If a family member has been diagnosed with HCM, your child should be screened for the condition.