Patient education: Hypertrophic cardiomyopathy in children (The Basics)

What is hypertrophic cardiomyopathy? — 

Hypertrophic cardiomyopathy, or "HCM," is a condition that makes the heart muscle get too thick (figure 1). When this happens, it can keep the heart from pumping blood as well as it should. This can cause breathing problems, chest pain, and other symptoms.

HCM is usually caused by a genetic problem that runs in families.

What are the symptoms of HCM in children? — 

Some children show no symptoms. But others do.

People with HCM sometimes have a heart murmur. This is an extra sound that doctors or nurses hear when they listen to the heart with a stethoscope. A doctor or nurse might find a murmur during a routine exam, such as before a child starts playing sports.

Babies and young children might have symptoms, such as:

●Being much more tired than usual

●Breathing fast

●Having trouble feeding

Other children might not have any symptoms until their teen years. Symptoms can include:

●Feeling short of breath, especially during exercise

●Chest pain – This is often worse during exercise.

●Fainting or feeling like they might faint

●Heart palpitations – These feel like the heart is pounding, beating hard or fast, or skipping beats.

Are there tests to check for HCM? — 

Yes. Tests can include:

●Electrocardiogram ("ECG") – This measures the electrical activity in the heart (figure 2). It can show if the heart is beating in a normal pattern and rhythm. It can also show thickening of the heart muscle. The doctor might have your child exercise during the test.

●Echocardiogram (also called an "echo") – This uses sound waves to create pictures of the heart (figure 3). This lets doctors measure the thickness of the walls of the heart, measure the size of the spaces or "chambers" inside the heart, and see how the heart pumps. The doctor might have your child exercise during the test.

●Genetic testing – This can show if your child has 1 of the abnormal genes that some people with HCM have.

●Cardiac MRI – This creates pictures of the heart. It can show parts of the heart that are hard to see with an echo.

If your child has HCM, other family members (siblings and parents) should get tested for it, too. Tests include a physical exam as well as an ECG and echo. Siblings usually need tests every year between ages 12 and 18. After age 18, most people only need to be tested once every 3 to 5 years. If your child has an abnormal gene, the doctor might recommend that other family members also get genetic testing to look for this.

How is HCM in children treated? — 

If your child does not have symptoms, they probably will not need treatment. If symptoms happen, treatments include:

●Medicines to slow the heart rate and help the heart muscle relax

●A device called a "defibrillator" – This can sense and control abnormal heartbeats. It is placed under the skin near the heart (figure 4).

●Surgery – Rarely, people with HCM might need surgery to remove part of the heart muscle. This is done only when medicines do not work.

What can I do to help my child? — 

You should:

●Ask your child's doctor or nurse how much water they should drink – For some people with HCM, not getting enough fluids can cause problems, such as fainting. Other people with HCM need to be careful not to have too much salt and water.

●Follow the doctor's instructions about physical activity – Exercising very hard can be dangerous or even life-threatening for children with HCM. But most people with HCM can safely do gentle exercise. Ask the doctor what types of activity are safe for your child.

●Help your child take all their medicines – The doctor might prescribe medicines to slow your child's heart rate and help their heart muscle relax.

●Make sure your child gets all their vaccines.

Your child's doctor or nurse might tell you to check your child's blood pressure. If so, they can teach you how. They can also tell you how often to check and what your child's normal numbers are. This will help you know when their numbers are too high or too low, so you can call their doctor for advice. Blood pressure is explained with 2 numbers. For instance, blood pressure might be "115 over 75."

What will my child's life be like? — 

Your child will probably need regular exams and tests, medicines, or other treatments. They might also need to avoid certain activities.

A few people with HCM get serious heart problems. But most people can live normal lives.

When should I call the doctor? — 

Call for emergency help right away (in the US and Canada, call 9-1-1) if:

●Your child faints.

●Your child cannot wake up or stay awake.

●Your child has trouble breathing.

●Your child's lips or face looks blue.

●Your child has chest pain.

●Your child feels like their heart is pounding, beating hard or fast, or skipping beats.

●Your child feels lightheaded or dizzy.

●Your child acts confused, irritable, or not like themselves.

Call for advice if:

●Your child's symptoms are worse than usual.

●Your child often feels very tired.

●Your child has signs of heart failure – These can include:

•Swelling in the legs, ankles, face, or eyelids

•Breathing faster than normal

•Coughing and wheezing a lot

•Nausea, vomiting, or belly pain

In babies, signs of heart failure can include getting tired and sweaty while feeding.

●You are concerned your child is not gaining enough weight.

More on this topic

Patient education: ECG and stress test (The Basics)
Patient education: Echocardiogram (The Basics)
Patient education: Hypertrophic cardiomyopathy in adults (The Basics)
Patient education: Syncope (fainting) (The Basics)
Patient education: Implantable cardioverter-defibrillators (The Basics)
Patient education: High blood pressure in children (The Basics)
Patient education: Checking your blood pressure at home (The Basics)

Patient education: Hypertrophic cardiomyopathy (Beyond the Basics)
Patient education: Implantable cardioverter-defibrillators (Beyond the Basics)
Patient education: High blood pressure in children (Beyond the Basics)