What is cardiomyopathy?

Cardiomyopathy is any disease of the heart muscle in which the heart loses its ability to pump blood effectively. In some instances, heart rhythm is disturbed, leading to irregular heartbeats, or arrhythmias. There may be multiple causes of cardiomyopathy, including viral infections. Sometimes, the exact cause of the muscle disease is never found.

How does cardiomyopathy differ from other heart disorders?

Cardiomyopathy differs from many of the other disorders of the heart in several ways, including the following:

• Cardiomyopathy can, and often does, occur in the young.
  
  
• The condition is fairly uncommon, affecting only about 50,000 Americans (adults and children).
  
  
• Cardiomyopathy is a leading cause for heart transplantation.
  
  
• The condition tends to be progressive and sometimes worsens fairly quickly.
  
  
• It may be associated with diseases involving other organs, as well as the heart.
  

Why is cardiomyopathy a concern?

Cardiomyopathy prevents the heart muscle from pumping enough blood to meet the body's needs.

What causes cardiomyopathy?

Viral infections that infect the heart are a major cause of cardiomyopathy. In some instances, cardiomyopathy is a result of another disease or its treatment, such as complex congenital (present at birth) heart disease, nutritional deficiencies, uncontrollable, fast heart rhythms, or certain types of chemotherapy for childhood cancers. Sometimes, cardiomyopathy can be linked to a genetic abnormality. Other times, the cause is unknown. Three types of cardiomyopathy affect both adults and children.

What types of cardiomyopathy commonly affect children?

The following types of cardiomyopathy commonly affect children:

• dilated (congestive) cardiomyopathy
  This is the most common form of cardiomyopathy. The heart muscle is enlarged and stretched (dilated), causing the heart to become weak and pump inefficiently. Other problems that may occur with dilated cardiomyopathy include the following:
  
  
  • irregular heart rhythms
  • risk of blood clots
  • congestive heart failure
    
    

  Various infections (including viral) which lead to an inflammation of the heart muscle (myocarditis) can cause this type of cardiomyopathy.

  Contact with toxins or very powerful therapeutic drugs, such as certain types of chemotherapy given to fight cancer, have been known to cause dilated cardiomyopathy. Heredity can also be a factor. Twenty percent of people with dilated cardiomyopathy have a parent or sibling with the disease. In many cases, a specific cause for this type of the disease is never identified.

  Because the heart muscle is weak and unable to pump enough blood to meet the body's demands, the body tries to preserve blood flow to essential organs such as the brain and kidneys by reducing blood flow to other areas of the body, such as the skin and muscles.

  The following are the most common symptoms of dilated cardiomyopathy. However, each child may experience symptoms differently. Symptoms may include:

  • pale or ashen skin color
  • cool, sweaty skin
  • rapid heart rate
  • rapid breathing rate
  • shortness of breath
  • fatigue
  • irritability
  • chest pain
  • poor appetite
  • slow growth
    
    

  Specific treatment for dilated cardiomyopathy will be determined by your child's physician based on:

  • your child's age, overall health, and medical history
  • extent of the disease
  • your child's tolerance for specific medications, procedures, or therapies
  • expectations for the course of the disease
  • your opinion or preference
    
    

  Your child's physician may recommend medications to accomplish the following:

  • help the heart beat more effectively
  • decrease the workload of the heart
  • decrease the oxygen requirements of the heart
  • prevent clots from forming
  • decrease inflammation of the heart
  • regulate irregular heartbeats
    
    

  In some cases, d ilated cardiomyopathy due to viral causes improves. In other cases, the condition worsens and transplantation of the heart may be considered. Consult your child's physician for more information regarding the specific outlook for your child.

• hypertrophic cardiomyopathy (Also known as hypertrophic obstructive cardiomyopathy, HOCM; asymmetric septal hypertrophy, ASH; or idiopathic hypertrophic subaortic stenosis, IHSS.)
  In this type of cardiomyopathy, the muscle mass of the left ventricle of the heart is larger than normal, or the wall between the two ventricles (septum) becomes enlarged. These abnormalities obstruct the blood flow from the left ventricle.

  The thickened muscle or septal wall can also affect one of the leaflets of the mitral valve, which separates the left atrium and the left ventricle. The valve leaflet becomes leaky, allowing blood to move backwards from the left ventricle into the left atrium, instead of forward to the body.

  Hypertrophic cardiomyopathy is often hereditary. One-half of children with the disease have a parent or sibling with varying degrees of left ventricular muscle or ventricular wall enlargement, although relatives may or may not have symptoms.

  Children with hypertrophic cardiomyopathy may have symptoms that increase with exertion or symptoms may be unpredictable.

  The following are the most common symptoms of hypertrophic cardiomyopathy. However, each child may experience symptoms differently. Symptoms may include:

  • shortness of breath on exertion
  • dizziness
  • fainting
  • chest pain
  • abnormal heart rhythms
    
    

  Specific treatment for hypertrophic cardiomyopathy will be determined by your child's physician based on:

  • your child's age, overall health, and medical history
  • extent of the disease
  • your child's tolerance for specific medications, procedures, or therapies
  • expectations for the course of the disease
  • your opinion or preference
    
    

  Your child's physician may recommend medications to accomplish the following:

  • decrease the workload of the heart
  • decrease the oxygen requirements of the heart
  • regulate irregular heartbeats
    
    

  Surgical treatment may include:

  • removal of part of the enlarged muscle
  • artificial pacemaker
  • heart transplantation
    
    

  Consult your child's physician for more information regarding the specific outlook for your child.

What is restrictive cardiomyopathy?

Restrictive cardiomyopathy, the least common type of cardiomyopathy in the US, occurs when the myocardium of the ventricles becomes excessively rigid, and the filling of the ventricles with blood between heart beats is impaired. This condition occurs rarely in children.

Restrictive cardiomyopathy usually results from another disease, which occurs elsewhere in the body. However, there are idiopathic (cause unknown) occurrences as well. Restrictive cardiomyopathy does not appear to be inherited, but some of the diseases that lead to the condition are genetically transmitted.

Conditions that may be associated with the development of restrictive cardiomyopathy include, but are not limited to, the following:

• scleroderma (a chronic, degenerative disease that affects the joints, skin, and internal organs)
• amyloidosis (a rare disease which causes the buildup of amyloid, a protein and starch, in tissues and organs)
• sarcoidosis (a rare inflammation of the lymph nodes and other tissues throughout the body)
• mucopolysaccharidosis (a condition in which mucopolysaccharides, or carbohydrates that bond with water to form a thick, jelly-like substance, accumulate in body organs)
• cancer

Radiation therapy for cancer treatment has also been associated with restrictive cardiomyopathy.

The following are the most common symptoms of restrictive cardiomyopathy. However, each child may experience symptoms differently. Symptoms may include:

• shortness of breath on exertion
• chest pain
• weakness
• swelling of the extremities

Specific treatment for restrictive cardiomyopathy will be determined by your child's physician based on:

• your child's age, overall health, and medical history
• extent of the disease
• your child's tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

Your child's physician may recommend medications to accomplish the following:

• decrease the workload of the heart
• decrease the oxygen requirements of the heart
• prevent blood clots from forming
• regulate irregular heartbeats

Surgical treatment may include:

• removal of part of the enlarged muscle
• artificial pacemaker insertion
• heart transplantation

Consult your child's physician for more information regarding the specific outlook for your child.