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What Is Cardiomyopathy?

Cardiomyopathy is when the heart muscle becomes weak and enlarged. This makes it hard for the heart to pump blood through the body.

Cardiomyopathy (KAR-dee-oh-my-OP-ah-thee) is a serious disease. Treatments can help with the symptoms and sometimes stop it from getting worse, but usually there's no cure. 

What Happens in Cardiomyopathy?

Cardiomyopathy weakens the heart muscle, or myocardium (my-oh-KAR-dee-um). This can lead to heart failure, 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 swelling in the legs and ankles (edema) and fluid in the lungs (pulmonary edema).

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

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.
  • hypertrophic cardiomyopathy: The heart muscle gets thicker.
  • 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.

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
  • 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?

Usually, doctors don’t find the cause of a person’s cardiomyopathy. This is called idiopathic cardiomyopathy.

Things that can cause the condition include:

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

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?

How doctors diagnose cardiomyopathy depends on which type a child has. Sometimes the problem is found early when a child develops a heart murmur.

Tests to check for cardiomyopathy include:

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 improve blood flow or prevent arrythmias

Some kids will need care in a pediatric intensive care unit (PICU).

If medicines don't work after a long time, 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:

Reviewed by: Amy W. Anzilotti, MD
Date Reviewed: 01-06-2021

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