Understanding Pediatric Cardiomyopathy: Causes, Symptoms and Treatment Options

Up to 5,000 American infants and children are diagnosed with pediatric cardiomyopathy each year. Learn more about this rare but potentially serious condition.

Cardiomyopathy, which is a general term for diseases of the heart muscle, is relatively rare in children, affecting only about 12 out of every 1 million Americans under the age of 18.

Among the approximately 1,000 to 5,000 new cases diagnosed each year, the majority are diagnosed in infants younger than 12 months old, followed by teens between the ages of 12 and 18. Cardiomyopathy that presents in children between the ages of one and 12 is considered very unusual.

One of the issues that makes pediatric cardiomyopathy uniquely complicated is that, unlike adults, children are still growing. It’s difficult to predict how the muscles of the heart will respond to each growth spurt the child experiences.

The good news is that our understanding of pediatric cardiomyopathy is improving every year. Today, there are experienced specialists and clinically proven treatment options available to help children affected by this condition.

What is Pediatric Cardiomyopathy?

Cardiomyopathy involves abnormalities in the muscle fibers of the heart, which contract and relax each time the heart beats. The prevalence and severity of symptoms can vary from patient to patient; however, for many, the condition is progressive, meaning it will make it harder and harder for the heart to pump blood over time. Without treatment, this can lead to more serious complications, including fatigue, irregular heartbeats (arrhythmias) and heart failure.

Pediatric cardiomyopathy can be classified into four broad categories:

Dilated Cardiomyopathy (DCM)

The most common form of pediatric cardiomyopathy, DCM occurs when the heart muscle tissue in one or both pumping chambers (ventricles) is unable to contract normally. Over time, the heart enlarges in an attempt to deliver more blood with each beat, causing it to weaken and potentially fail.

Hypertrophic Cardiomyopathy (HCM)

HCM is the second most common form of pediatric cardiomyopathy, occurring when abnormal muscle tissue growth causes the walls of the ventricles to thicken, making it harder for the heart to fill and contract properly. This thickening can lead to arrhythmias and even obstruct blood flow out of the ventricles.

Restrictive Cardiomyopathy (RCM)

In cases of RCM, it’s the relaxation of the heart that is abnormal rather than the contraction. As the walls of the ventricles stiffen, the heart is unable to fill with an adequate amount of blood, which can lead to extreme fatigue and heart failure over time.

Arrhythmogenic Right Ventricular Dysplasia (ARVD)

This is the least common type of pediatric cardiomyopathy. It is extremely rare in young children, typically presenting in teens and young adults — often in those who are more physically active and athletic. ARVD occurs when healthy heart muscle is replaced with scar tissue and fat and can lead to arrhythmias and serious contraction issues (read Stan’s story).

What Causes Pediatric Cardiomyopathy?

In most cases of pediatric cardiomyopathy, the cause is unknown (idiopathic). Depending on the type of cardiomyopathy, the condition may be “inherited” or “acquired.” Inherited means the condition was passed on genetically by a parent, whereas acquired means the child wasn’t born with the disease, but developed it over time because of another condition or influencing factor.

In other words, for some children, cardiomyopathy will occur because of genetics, whereas others will develop the condition because of an infection or disease, such as myocarditis — a viral infection that causes inflammation in the heart. Researchers also believe that there is a link between some types of cardiomyopathy and excessive exposure to certain toxins and/or drugs, such as alcohol, heavy metals and chemotherapy drugs.

Symptoms and Diagnosis

Unfortunately, pediatric cardiomyopathy often goes undetected until the late stages of the disease when heart failure symptoms appear. When there are no obvious symptoms, such as irregular heartbeats or a heart murmur (an unusual sound heard between heartbeats), or a documented reason for diagnostic testing based on family history, cardiomyopathy can easily be overlooked during a routine check-up.

Early warning signs include:

  • Chest discomfort or pressure
  • Rapid, pounding and/or fluttering heartbeats
  • Dizziness, lightheadedness and fainting spells
  • Extreme fatigue and loss of appetite
  • Loss of breath from mild exertion, or even at rest

As the condition progresses, more serious symptoms may appear, including swelling of the legs, ankles and feet, and bloating and/or fluid buildup in the abdomen.

When a child is suspected of having cardiomyopathy, the first step is to visit a pediatric cardiologist, who will conduct a thorough evaluation of the child’s medical and family history and perform a physical examination. A number of cardiac tests may be used to make a diagnosis, including non-invasive methods such as X-ray, magnetic resonance imaging (MRI), echocardiograms (EKG), electrocardiogram (ECG) and genetic testing, or minimally invasive procedures, such as cardiac catheterization.

Learn more about these diagnostic methods via the Children’s Cardiomyopathy Foundation.

How is Pediatric Cardiomyopathy Treated?

Treating pediatric cardiomyopathy requires the coordinated effort of medical professionals across a range of fields and specializations, such as pediatric cardiology, hematology, pediatric cardiothoracic surgery, physical and occupational therapy and more.

Depending on the type of cardiomyopathy and the symptoms present, standard treatments may include lifestyle and dietary changes, medication, non-surgical procedures, implantable devices and surgery.

In the most severe cases, the condition may continue to progress until medications, surgical treatments and other therapies are no longer effective. At this point, the child may require a heart transplant — a procedure in which the failing heart is removed and replaced with a healthy, matching donor heart. Pediatric cardiomyopathy is the number one cause of heart transplantation in children.

More Information

For in-depth information about pediatric cardiomyopathy, associated conditions, treatment options and more, refer to the websites and resources listed below: