What is cardiomyopathy?

Cardiomyopathy is a disease where the heart muscle, or myocardium, becomes too thick, stiff or enlarged. This affects the heart’s ability to pump blood and maintain its rhythm.

There are different types of cardiomyopathies. These include:

Dilated cardiomyopathy is the most common type in adults and children. This is when the pumping chambers (called ventricles) of the heart become weak and enlarged. Some children with a dilated heart have no symptoms, while others develop heart failure. The symptoms of heart failure can include difficulty breathing and eating, excessive sweating and not growing properly. There are many different causes of dilated cardiomyopathy. When cardiomyopathy occurs in many family members through many generations, it is known as familial dilated cardiomyopathy.

Hypertrophic cardiomyopathy is when one or more of the pumping chambers (or ventricles) in your child's heart become unusually thickened, or "muscle-bound." This condition can affect the left ventricle, which pumps blood to the body, or both the right ventricle (which pumps blood to the lungs) and the left. Hypertrophic cardiomyopathy is often associated with abnormal heart rhythms, which can lead to sudden death. This condition may also run in families. If anyone in your family has hypertrophic cardiomyopathy, it’s recommended that all family members are screened for the condition.

Restrictive cardiomyopathy: The rarest type of cardiomyopathy in children. The chambers of the heart become stiff, resulting in improper heart muscle relaxation, so that your child's heart cannot fill with blood adequately. Abnormal heart rhythms may also occur with this disease. There are no medicines that are known to improve patients with restrictive cardiomyopathy, and a heart transplant is often recommended for children with this condition.

Noncompaction cardiomyopathy is when the heart muscle appears spongy on an echocardiogram. Noncompaction cardiomyopathy may be caused by abnormal development of the heart muscle cells. Normally, extra muscle bundles (called trabeculations) in the left ventricle become smooth as the heart develops. In noncompaction cardiomyopathy, there are easily noticeably muscle bundles in the left ventricle. This form of cardiomyopathy can exist alone or with another type of structural heart disease. Noncompaction cardiomyopathy can also be part of an underlying syndrome or even have no identifiable cause (which is referred to as idiopathic noncompaction cardiomyopathy). 

In noncompaction cardiomyopathy, the heart muscle can become dilated, like in dilated cardiomyopathy, or too thick, like in hypertrophic cardiomyopathy. Some children can have trabeculations in the left ventricle of a normal-sized heart that functions normally. This is referred to as hypertrabeculation. 

Noncompaction is the most unpredictable type of cardiomyopathy. In young children, it can cause a poorly functioning heart and symptoms of illness, while in older children and adults, it may not cause any symptoms.

Causes of cardiomyopathy

Cardiomyopathy can have no known cause (idiopathic), be inherited (passed down through families because of genetic differences), or occur as result of a mitochondrial or metabolic disorder. 

Rarely, children can also develop cardiomyopathy due to chemotherapy drugs or hypertension. The causes of cardiomyopathy differ in adults and can include long standing diabetes and previous heart attack.

With improvements in genetic testing, doctors are more often able to identify the cause of cardiomyopathy.

Signs and symptoms of cardiomyopathy

Symptoms of cardiomyopathy vary widely in type and severity.

Sometimes infants have symptoms of cardiomyopathy shortly after birth. These symptoms can include:

• Difficulty breathing
• Sweating while feeding or difficulty with feeding
• Poor weight gain
• Irritability, lethargy, unresponsiveness or seeming “out of it” 

Sometimes symptoms don’t appear until the child is older. These symptoms can include:

• Heart murmur, or abnormal heart sound when a doctor listens with a stethoscope
• Difficulty exercising, difficulty breathing and/or chest pains with exercise
• Dizziness or fainting
• Unusual fatigue
• Heart palpitations
• Vomiting or decreased appetite
• Unexplained weight gain

Testing and diagnosis for cardiomyopathy

Diagnosis of cardiomyopathy may include:

• Chest x-ray
• Echocardiogram (also called echo or ultrasound), which is when sound waves create an image of the heart
• Electrocardiogram (ECG or EKG), which is a record of the electrical activity of the heart
• Cardiac magnetic resonance imaging (MRI), which is a 3-D image that shows the heart’s structures in detail
• Cardiac catheterization, which is when a thin tube is inserted into the heart through a vein and/or artery in the leg to provide detailed information about the structure and function of the heart 

If one person in a family is diagnosed with a cardiomyopathy, it may be important that a cardiologist evaluates other family members to assess their risk of cardiomyopathy, even if they don’t have symptoms of heart disease. Children’s Hospital of Philadelphia (CHOP) and the University of Pennsylvania Health System (Penn) have created the Familial Cardiomyopathy Program to ensure that family members of patients with cardiomyopathies have the proper cardiac screening and genetic testing.

Treatments for cardiomyopathy

There are many treatment options for cardiomyopathy, depending on the type and severity.

Medicines

Depending on the type of cardiomyopathy, doctors may prescribe medicines that help decrease the size of a dilated heart, relax the heart, increase the pumping strength, regulate the rhythm of the heart, or help in some other way. Often, several medications are used at the same time to meet these goals.

Pacemakers and implantable defibrillators

These devices help control the heart rhythm, so the heart doesn’t beat too slowly or in an irregular rhythm. The devices are implanted under the skin and connected to the heart with tiny wires called leads.

Ventricular assist devices

These devices are used to pump blood when the heart is too weak to do it on its own. The device pumps blood from the left ventricle to the body through the aorta, the largest artery in the body. Sometimes these devices can stay in for months or even years and can be used as a bridge to recovery of heart function or as a bridge to heart transplant. With some ventricular assist devices, children can even live at home. 

Septal myectomy

In patients with hypertrophic cardiomyopathy, sometimes the tissue that divides the two sides of the heart (called the septum) bulges into the left ventricle, which can block blood flow to the body. If symptoms are not helped by medications, a surgeon can remove the bulging portion of the septum through a surgery called septal myectomy. This surgery is rarely used.

Heart transplant

Heart transplantation can be considered in children with symptoms of heart failure that interfere with daily activities and growth.

Follow-up care for cardiomyopathy

Children and teenagers with cardiomyopathies will continue to see a pediatric cardiologist regularly. The level of care needed will depend on the severity of the cardiomyopathy. Many people with cardiomyopathy see a specialist and may be referred to doctors in genetics, metabolism, or neurology if an inherited or related disorder is suspected.

Our pediatric cardiologists follow patients until they are young adults. The Philadelphia Adult Congenital Heart Center, a joint program of CHOP and Penn Medicine, meets the unique needs of adults who were born with heart defects. 

At CHOP’s Cardiac Center, we support our adolescent and young adult patients through a smooth and seamless transition to adult cardiology care at the Philadelphia Adult Congenital Heart Center or, if desired, to a cardiologist with congenital heart disease expertise in another location.