Hypertrophic cardiomyopathy (HCM) in children

What is hypertrophic cardiomyopathy (HCM) in children?

Pediatric HCM causes all or part of the heart muscle to become thicker than usual (hypertrophic). The thicker heart muscle often has difficulty relaxing, which can make it harder to pump blood. This in turn can lead to irregular heart rhythms (arrhythmia), and in some cases, heart failure.

While most children with HCM lead long lives, it is a serious condition that can cause heart failure pediatric cardiologist with expertise in caring for individuals with this condition.

What are the signs and symptoms of hypertrophic cardiomyopathy (HCM) in children?

• Shortness of breath

• Chest pressure or pain

• Irregular heartbeats (fast or slow)

• Light-headedness, dizziness, or fainting

• Swelling/pain in the legs, arms and abdomen

• Energy loss

• Lack of appetite

• Slow growth or inability to gain weight

How is hypertrophic cardiomyopathy (HCM) in children diagnosed?

Pediatric hypertrophic cardiomyopathy is a complex condition that can start at any time in a child’s life, which can make diagnosis challenging. This is why it’s important to work with experts who know what to look for.

Echocardiogram - At Children’s Health, we use several different tests to help detect hypertrophic cardiomyopathy in infants, children and teenagers. The most common test we use to diagnose HCM is a heart ultrasound (echocardiogram), which uses sound waves to create pictures of the heart. This helps our team see if the heart muscle is thicker than it should be, and can show whether the heart’s chambers are working as usual.

Other tests we may use to diagnose HCM include:

• Pediatric magnetic resonance imaging (MRI) - Used to see if there is scarring on the heart.

• Holter monitoring - Used to detect heart rhythm over a few days.

• Exercise stress testing - Used to see how the heart responds to stress during physical activity.

• Blood tests - Used to look for signs of heart failure

What causes hypertrophic cardiomyopathy (HCM) in children?

Pediatric hypertrophic cardiomyopathy has many causes. The condition can be passed to children from their parents through genes (inherited) or it can be caused by spontaneous gene changes. Other times, there is no clear cause (idiopathic).

In some cases, HCM is caused by genetic mutations that affect only the heart muscle. In other cases, HCM is a result of another gene-related condition.

Common types of genetic conditions that can cause HCM include:

• Metabolic syndromes - where the body doesn’t process fats, proteins or carbohydrates appropriately.

• Mitochondrial disorders - where the body can’t completely burn food and oxygen to create energy.

• Neuromuscular disorders - where muscles outside the heart are also affected

How is hypertrophic cardiomyopathy (HCM) in children treated?

While there is currently no cure for hypertrophic cardiomyopathy, experts at Children’s Health can help ease your child’s symptoms and manage complications and challenges as they arise.

• Finding the right level of physical activity for your child - Children with HCM should be restricted from competitive sports or high-intensity exercise, which increase the risk of a sudden cardiac arrest. However, regular physical activity is still very important and we will help you find what level and types of physical activity are best for your child.

• Working with your child’s school - We help you inform your child’s school and coaches about HCM. For example, we can provide a letter informing the school that your child should not be graded on exercise performance (which could unintentionally pressure your child to push past their limits).

• Prescribing medication - Sometimes medications can help manage symptoms or treat HCM. The most common medications are beta blockers, which slow down the heart rate and give the heart more time to fill with blood in between heartbeats.

• Providing an implantable cardioverter-defibrillator (ICD) - Our team may offer an implantable cardioverter-defibrillator (ICD) if your child is at high risk of sudden cardiac death. An ICD will monitor your child’s heart rhythm and can deliver an electrical signal to normalize the heart rhythm if needed.

• Walking through surgical options - Uncommonly, if medication isn’t relieving your child’s symptoms, we may discuss surgery to remove some of the abnormal heart muscle (surgical myectomy). In rare cases, we may need to discuss heart transplantation.