What is cardiomyopathy?

Cardiomyopathy is disease of the heart muscle. It makes it harder for the heart to pump blood. There are different types of the disease. Each of these cause the heart muscle to get larger, thicken, or become stiff. Cardiomyopathy keeps the heart muscle from pumping enough blood to meet the body's needs.

There are 4 types of cardiomyopathy that can affect both adults and children:

• Dilated cardiomyopathy (DCM)
• Hypertrophic cardiomyopathy (HCM)
• Restrictive cardiomyopathy (RCM)
• Arrhythmic right ventricular cardiomyopathy (ARVC)

How does cardiomyopathy differ from other heart problems?

Cardiomyopathy differs from many other heart problems in several ways:

• It often happens in children.

• It tends to get worse. It sometimes gets worse quickly.

• It may be linked to diseases of other organs besides the heart.

• It's a leading cause of the need for heart transplants.

What causes cardiomyopathy?

Cardiomyopathy can have a number of causes. These include: 

• Genes
• Viral infections
• High blood pressure
• Heart rhythm problems
• Congenital heart defects
• Certain medicines

Often, the exact cause is never found. This is called idiopathic. Cardiomyopathy can lead to heart rhythm problems (arrhythmias) or heart failure.

Viral infections in the heart are a common cause of cardiomyopathy. In some cases, it's a result of another disease or its treatment. For example, it might be caused by a heart problem a child is born with (congenital). Or it might be caused by nutrition problems, very fast heart rhythms, or certain types of chemotherapy. Cardiomyopathy can sometimes be linked to a gene change. But the exact cause is often unknown. 

What is dilated cardiomyopathy (DCM)?

DCM is the most common form of cardiomyopathy. The heart muscle becomes enlarged and stretched (dilated). This causes the heart to become weak. It can't pump well. Problems that may occur with DCM include:

• Heart rhythm problems

• Blood clots

• Heart failure

• Leaky mitral valve (mitral valve regurgitation)

Infections lead to inflammation of the heart muscle (myocarditis). The infections are often from viruses. This is the most common cause of DCM.

DCM can also be caused by having contact with toxins or very strong medicines such as some types of chemo. Genes can also play a role. About 1 in 5 people with DCM have a parent or sibling with the disease. In many cases, the cause for this type of the disease is not found.

When the heart muscle is weak and can't pump enough blood to meet the body's demands, the body may try to reduce blood flow to some areas of the body. This keeps blood flow to vital organs such as the brain and kidneys. Areas that may get less blood include the skin and muscles.

These are the most common symptoms of DCM:

• Pale or gray skin color

• Cool, sweaty skin

• Rapid heart rate

• Rapid breathing rate

• Shortness of breath

• Tiredness (fatigue)

• Irritability

• Chest pain

• Loss of appetite

• Slow growth

Your child's healthcare provider may recommend medicines to:

• Help the heart beat better

• Decrease the workload of the heart

• Decrease the oxygen needs of the heart

• Prevent blood clots

• Decrease inflammation of the heart

• Control heartbeat problems

In some cases, DCM caused by a virus gets better over time. In other cases, the condition gets worse. Your child may need a heart transplant. Talk with your child's healthcare provider for more information about your child's case.

What is hypertrophic cardiomyopathy (HCM)?

In HCM, the muscle of the heart becomes thicker than normal. This blocks some blood flow to the rest of the body.

The thickened muscle may also affect the mitral valve. This valve separates the left atrium and the left ventricle. The valve may become leaky. This lets blood flow backwards from the left ventricle into the left atrium, instead of forward to the rest of the body.

HCM is often inherited. About 1/2 of children with the disease have a parent or sibling with some thickening of the left ventricular muscle or ventricular wall. These relatives may or may not have symptoms.

Children with HCM may have symptoms that get worse with exertion. But symptoms may often be hard to predict.

These are the most common symptoms of HCM:

• Shortness of breath with exertion

• Dizziness

• Fainting

• Chest pain

• Abnormal heart rhythms

Your child's healthcare provider may recommend medicine to:

• Decrease the workload of the heart

• Decrease the oxygen needs of the heart

• Control irregular heartbeats

Surgery may include:

• Removal of part of the enlarged muscle

• Implantation of a pacemaker or defibrillator

• Heart transplant

Talk to your child's healthcare provider for more information about your child's case.

What is restrictive cardiomyopathy (RCM)?

RCM is an uncommon type of cardiomyopathy in the U.S. It occurs when the heart muscle of the ventricles becomes too stiff. Then the ventricles don't relax to fill with blood between heartbeats. This condition rarely occurs in children.

RCM is often caused by a condition that affects the rest of the body. But in some cases the cause is unknown (idiopathic). RCM doesn't appear to be inherited. But some of the diseases that lead to the condition may be genetic.

Health conditions that may be linked with RCM include:

• Scleroderma, a chronic, degenerative disease that affects the joints, skin, and internal organs

• Amyloidosis, a rare disease which causes the buildup of a protein and starch called amyloid in tissues and organs

• Sarcoidosis, a rare inflammation of the lymph nodes and other tissues throughout the body

• Mucopolysaccharidosis, a condition in which carbohydrates that bond with water to form a thick, jelly-like substance (mucopolysaccharides) build up in body organs

• Cancer

Radiation therapy for cancer treatment has also been linked with RCM.

These are the most common symptoms of RCM:

• Shortness of breath with exertion

• Chest pain

• Weakness

• Swelling of the arms or legs

Your child's healthcare provider may recommend medicines to:

• Decrease the workload of the heart

• Decrease the oxygen requirements of the heart

• Prevent blood clots

• Control irregular heartbeats

Surgery may include:

• Pacemaker or defibrillator insertion

• Heart transplant

Talk to your child's healthcare provider for more information about your child's case.

What is arrhythmic right ventricular cardiomyopathy (ARVC)?  

ARVC is a rare type of inherited cardiomyopathy. It occurs if the muscle tissue in the right ventricle has scar tissue. The scar tissue disrupts the heart's electrical system. This causes arrhythmias.  ARVC usually affects teens and young adults. Symptoms include heart palpitations and fainting after physical activity.  It can cause sudden cardiac arrest in young athletes. 

Treatment often includes:

• Activity restriction

• Medicines that slow the heart rate and treat symptoms of heart failure

• Implantable defibrillators

• Heart transplant in severe cases