Cardiomyopathy, which means heart muscle disease, is rare in children. This condition weakens the heart muscle, making it harder for the heart to pump blood to the body.

A normal heart has four chambers: two atria that receive blood and two ventricles that pump blood out. Cardiomyopathy most commonly affects the left ventricle, but it can affect any area of the heart.

Some people with mild cases do not experience symptoms, but severe cardiomyopathy can cause serious complications. Early diagnosis and treatment can help improve your child’s quality of life and reduce the risk of complications.

Cardiomyopathy Causes and Risk Factors

Children can inherit cardiomyopathy from a genetic mutation passed on through a parent. Researchers have identified hundreds of different genetic mutations associated with inherited (or familial) cardiomyopathy. Other causes of cardiomyopathy are not genetic, and occur because of a separate disease. This is sometimes called an acquired cardiomyopathy.

In most cases of pediatric cardiomyopathy, the cause is idiopathic, which means unknown. But some medical conditions, lifestyle choices and environmental factors increase the risk of cardiomyopathy. These risk factors include:

  • Family history, such as a close relative having cardiomyopathy, heart failure or sudden cardiac arrest
  • Heart conditions, including congenital heart defects, coronary artery disease, heart attack or myocarditis (heart muscle infection)
  • Infection or disease that can damage the heart, like amyloidosis, hemochromatosis or sarcoidosis
  • Other medical conditions, such as autoimmune, connective tissue or endocrine conditions
  • Toxin exposure, including long-term drug or alcohol misuse or exposure to environmental toxins like heavy metals

Cardiomyopathy Types

Cardiomyopathy can occur as an isolated condition or because of another condition. Primary cardiomyopathy is when the condition affects only the heart. Secondary cardiomyopathy is when it results from another condition affecting the body as a whole.

Doctors further classify cardiomyopathy into several types, based on physical characteristics and symptoms. These types include:

  • Dilated cardiomyopathy (DCM): This type is the most common type of cardiomyopathy in children. With dilated cardiomyopathy, one of the chambers of the heart dilates (gets bigger), and the chambers don’t contract properly. It often starts in the left ventricle but can spread to other chambers. DCM can cause heart valve problems, irregular heartbeats, blood clots and heart failure.
  • Hypertrophic cardiomyopathy (HCM): Hypertrophic cardiomyopathy is often inherited. With HCM, the heart muscle thickens and stiffens. These changes cause the heart to pump less blood per heartbeat. Many people with hypertrophic cardiomyopathy don’t have symptoms. When symptoms occur, they often appear during periods of rapid growth or during strenuous exercise. In obstructive HCM, both the heart muscle and heart wall (septum) thicken.
  • Restrictive cardiomyopathy (RCM): RCM is the least common type of cardiomyopathy and is extremely rare in children. With RCM, the heart muscle stiffens, making it harder for blood to flow into the heart. This stiffness causes blood to back up in the heart and body, which can lead to heart failure in severe cases. RCM can be difficult to diagnose because the first symptoms often relate to the lungs, not the heart.
  • LV Non-compaction cardiomyopathy (LVNC): This cardiomyopathy is characterized by having “spongy” heart muscle that is not firmly compacted, and therefore does not allow the ventricle to squeeze properly. There are several varieties which can mimic other forms of cardiomyopathy. Sometimes this disease can be present in newborn infants.

Other types: There are several other types of cardiomyopathy rarely seen in children. These include arrhythmogenic right ventricular cardiomyopathy (ARVC), and forms of amyloidosis, Fabry disease, hemochromatosis and other conditions.

Cardiomyopathy Symptoms

Some children never have cardiomyopathy symptoms, while others have symptoms ranging from mild to severe. Early diagnosis and treatment may help prevent symptoms from worsening.

Symptoms can affect many body systems. They include:

  • Cardiovascular symptoms, such as chest pain, arrhythmia (irregular heartbeat) and swelling of the legs and feet
  • Digestive symptoms, including poor appetite, lack of growth, feeding difficulties (in infants) and failure to thrive
  • Neurological symptoms, such as dizziness, excessive sweating, fainting and fatigue (especially after physical activity)
  • Respiratory symptoms, including shortness of breath (especially after physical activity) and coughing

Hypertrophic cardiomyopathy with no symptoms

People with hypertrophic cardiomyopathy often don’t have symptoms. When this happens, doctors call it asymptomatic hypertrophic cardiomyopathy.

In rare cases, asymptomatic HCM can cause sudden cardiac arrest, especially in young athletes. That’s why it’s so important to see a doctor if you have a family history of HCM, heart failure or sudden cardiac arrest. If your child has HCM, a pediatric cardiologist can make a monitoring and treatment plan to reduce the risk of serious complications.

Our team is at the forefront of research and guidance for hypertrophic management in children, with leading experts in this field. It is important that children with suspected HCM be seen and properly evaluated by a pediatric expert in the field, as it is very different in children than adults.

Cardiomyopathy Diagnosis

Your child’s doctor starts by taking a family history and performing a physical exam. The doctor listens to your child’s heart and lungs and looks for any physical symptoms like swelling. Then, the doctor may order diagnostic tests.

Diagnostic tests

The main way to diagnose dilated or hypertrophic cardiomyopathy is with an echocardiogram. An echocardiogram uses sound waves to create pictures of the heart. The doctor looks for dilated chambers and slower pumping for DCM or thickened heart walls for HCM.

Doctors often use an electrocardiogram (EKG) and echocardiogram to diagnose restrictive cardiomyopathy. An EKG measures the heart’s electrical activity. It can also show signs of enlarged chambers or thickened heart muscle.

Your child’s doctor may also order other tests or procedures to confirm the diagnosis, including:

Cardiomyopathy Treatment

Children who have cardiomyopathy but don’t have symptoms may not need treatment. For those who do need treatment, options vary based on the type of cardiomyopathy and severity of symptoms.

The goals of cardiomyopathy treatment are to:

  • Prevent the disease from getting worse
  • Control symptoms to improve health and quality of life
  • Manage any other conditions or risk factors that may lead to complications

Lifestyle changes

Lifestyle changes may help manage symptoms and reduce the risk of complications. They include:

  • Eating a healthy diet
  • Getting regular exercise
  • Getting enough sleep
  • Managing any other health conditions
  • Reducing stress
  • Avoiding alcohol, cigarettes and drug use


When lifestyle changes aren’t enough, the doctor may recommend medication to treat cardiomyopathy symptoms. These medications include:

  • Antiarrhythmics to prevent irregular heartbeat
  • Anticoagulants to prevent blood clots
  • Corticosteroids to reduce inflammation
  • Diuretics to reduce excess fluid retention and balance electrolytes
  • Specific heart failure drugs to improve the contraction of heart muscle.

Surgeries and procedures

If medication and lifestyle changes aren’t enough, the doctor may suggest:

  • Surgically implanted device: A surgeon inserts a pacemaker or implantable cardioverter defibrillator into the body to help your child’s heart function better. These devices can help regulate your child’s heartbeat to prevent arrhythmias. For severe cardiomyopathy, a left ventricular assist device (LVAD) can help the heart pump blood to the body.
  • Septal myectomy: Specifically, in older children or adolescents with Hypertrophic Cardiomyopathy, a surgical procedure removes part of the thickened heart wall to improve blood flow leaving the left ventricle. Expert pediatric heart surgeons perform this open-heart surgery to treat severe obstructive hypertrophic cardiomyopathy that hasn’t responded well to medication.
  • Heart transplant: Your child receives a new, healthy heart from a donor. This treatment is a last resort if cardiomyopathy has progressed to end-stage heart failure. Pediatric cardiomyopathy is the primary reason for pediatric heart transplants.

Cardiomyopathy Care at Children’s Hospital Los Angeles

At CHLA, your child receives excellent care from world-class experts. Learn more about our Cardiomyopathy and Heart Failure Program.