What Is Cardiomyopathy?

Cardiomyopathy is disease of the heart muscle. It is a serious condition. Treatments can help with symptoms and sometimes stop cardiomyopathy (KAR-dee-oh-my-OP-ah-thee) from getting worse, but there is no cure.

What Are the Types of Cardiomyopathy?

The main types of cardiomyopathy are:

Dilated cardiomyopathy: The heart muscle gets thinner. This is the most common type in children. The chamber becomes too big and squeezes poorly, which means the heart can’t pump blood the way it should. If the blood gets backed up (“congested”) in the heart, it is called congestive heart failure (CHF). It leads to fluid in the lungs (pulmonary edema) and sometimes liver enlargement and swelling of the legs (peripheral edema).

Hypertrophic cardiomyopathy: The heart muscle, or myocardium (my-oh-KAR-dee-um), is too thick. So blood might not be able to leave the heart and may not be delivered to the body normally (obstruction). The heart may also be more likely to beat too fast. As with other types of cardiomyopathy, the heart can become weak or stiff.

Restrictive cardiomyopathy: The heart muscle gets stiff. Kids rarely get this type.

All types happen because the heart muscle changes. But their symptoms, treatments, and outlooks are different.

Cardiomyopathy also can lead to a life-threatening arrhythmia (abnormal heartbeat), heart valve problems, and blood clots.

What Are the Signs & Symptoms of Cardiomyopathy?

Some people with cardiomyopathy don’t have any symptoms. Others only notice signs when the condition gets worse.

Cardiomyopathy symptoms get worse over time. If heart failure develops, these can include:

• feeling very tired after normal activity
• inability to lie flat (orthopnea)
• a fast heart rate
• shortness of breath, breathing fast, or trouble breathing
• chest pain
• swelling in the legs, ankles, and feet
• belly bloating
• in infants, trouble feeding and poor weight gain (failure to thrive)

Other symptoms can include heart palpitations; and dizziness, lightheadedness, or fainting.

What Causes Cardiomyopathy?

Hypertrophic cardiomyopathy: Most children with hypertrophic cardiomyopathy have a genetic mutation that changes the structure of an important muscle cell protein.

Dilated cardiomyopathy: Genetic mutations may cause dilated cardiomyopathy. But it also can happen because of:

• infection of the heart muscle (myocarditis)
• nutritional deficiencies (in children)
• drug and alcohol abuse and coronary artery disease (in adults)
• metabolic disorders
• exposure to toxins
• some chemotherapy medicines

Restrictive cardiomyopathy: Genetic mutations can cause this type, as can scarring of the heart muscle, tumors of the heart muscle, and other problems.

People of any age can have cardiomyopathy. Some types run in families. When someone is diagnosed with cardiomyopathy, their close family members might need to get tests to see if they also have it.

How Is Cardiomyopathy Diagnosed?

Cardiomyopathy may be diagnosed at any age. Doctors may suspect the condition if someone has:

• symptoms of heart failure
• a new heart murmur
• a family history of cardiomyopathy or early or sudden death

Tests to check for cardiomyopathy include:

• a chest X-ray
• an electrocardiogram (EKG)
• blood tests
• an echocardiogram (ECHO)
• imaging tests, such as an MRI or CT scan
• a cardiac catheterization

How Is Cardiomyopathy Treated?

Depending on the type of cardiomyopathy and how sick a child is, treatment may include:

• medicines to:
  • improve how the heart beats
  • lower blood pressure (so the heart doesn’t have to work as hard to pump blood)
  • get rid of extra fluid in the lungs or body
  • treat arrythmias
• surgeries to improve blood flow or prevent arrythmias
• an implantable device to support improved blood flow or prevent arrythmias

Some kids will need care in a cardiac intensive care unit.

Some children may require ventricular assist device support or a heart transplant. Depending on how sick a child is when they are diagnosed, a heart transplant is often the best option for treating heart failure due to cardiomyopathy. Cardiomyopathy is the most common reason for heart transplants in children and teens.

How Can Parents Help?

Although cardiomyopathy is a chronic (ongoing) condition. But with the help of a cardiology care team, many children can find a way to be active and live a full life. 

To help your child get the best care possible:

• Give medicines as directed by the doctor.
• Go to all follow-up doctor visits.
• Help your child do activities the care team told you are safe and avoid those that are risky.

If your child has a long-term heart condition, it can feel overwhelming. But you're not alone. To find support, talk to anyone on the care team. Resources are available to help you and your child. You can also find help and support online at:

• The American Heart Association
• Children’s Cardiomyopathy Foundation