Cardiomyopathy

A cardiomyopathy is a disease of the heart muscle that reduces the heart's ability to pump blood effectively. Different kinds of cardiomyopathy cause the heart to enlarge (dilated cardiomyopathy), thicken (hypertrophic cardiomyopathy) or become stiff (restrictive cardiomyopathy). Cardiomyopathies can result from a number of causes, including viral infections, exposure to certain medicines and treatments, and symptoms of other medical conditions. They may also be inherited as an isolated problem. Sometimes, the exact cause of the muscle disease is never found. In addition to cardiomyopathies making the pumping function of the heart weaker, they may also lead to irregular heart rhythms, which can be life threatening.

How does a cardiomyopathy differ from other heart conditions?

A cardiomyopathy differs from many of the other disorders of the heart in several ways:

• A cardiomyopathy can, and often does, occur in children.
• The disease tends to be progressive and can worsen fairly quickly.
• It may be associated with diseases involving other organs as well as the heart.
• Cardiomyopathies are the leading cause for pediatric heart transplants.
• Cardiomyopathies may be clinically undetectable for some time and then suddenly present dramatically.

What causes cardiomyopathy?

Viral infections that infect the heart are a major cause of cardiomyopathy. In some cases, cardiomyopathy is a result of another disease or its treatment, such as a complex congenital heart defect, nutritional deficiencies, very fast and sustained abnormal heart rhythms or certain types of chemotherapy used to treat cancer. Frequently, cardiomyopathies are the result of a genetic problem abnormality passed down through families.

What are the different types of cardiomyopathy?

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

• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy
• Arrhythmic right ventricular dysplasia (ARVD)
  • ARVD is a rare type of cardiomyopathy affecting only 1 in 5,000 people. It occurs if the muscle tissue in the right ventricle is infiltrated by scar tissue. This process disrupts the heart's electrical system, causing arrhythmias.

Dilated cardiomyopathy is the most common form of cardiomyopathy. The heart muscle becomes enlarged and stretched, or dilated. This causes the heart to become weak and pump inefficiently. Problems that may occur with dilated cardiomyopathy include:

• Irregular heart rhythms
• Risk of blood clots
• Heart failure
• Leaky mitral valve

What causes dilated cardiomyopathy?

Various infections, including viral, that lead to 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 terminate cancer, have been known to cause dilated cardiomyopathy. Dilated cardiomyopathy can also be “familial” and is the result of an abnormality in one's DNA. About 20 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, though it is likely due to an abnormality in the DNA, is never found.

What are symptoms of dilated cardiomyopathy?

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

The most common symptoms of dilated cardiomyopathy 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
• Diminished ability to exercise or keep up with peers

How is dilated cardiomyopathy treated?

Your child's healthcare provider may recommend medication to:

• Help the heart beat more effectively.
• Decrease the workload of the heart.
• Decrease the oxygen requirements of the heart.
• Prevent blood clots from forming.
• Decrease inflammation of the heart.
• Regulate irregular heartbeats.

Dilated cardiomyopathy may also be treated by using a pacemaker or an implanted defibrillator (ICD) if patients are at risk for arrhythmia. We work closely with our Advanced Cardiac Therapies team within our Heart Center. This program provides innovative technologies for advanced heart failure, including medical therapies, mechanical support and heart transplantation.

In some cases, dilated cardiomyopathy due to viral causes improves over time. In other cases, the condition worsens, and a heart transplant may be considered. Talk to your child's healthcare provider for more information about his specific outlook.

Restrictive cardiomyopathy, the least common type of cardiomyopathy in the U.S., occurs when the myocardium (heart muscle) of the ventricles becomes excessively stiff. When this happens, the ventricles do not relax normally, preventing blood from filling the pumping chambers of the heart between heartbeats. This condition occurs rarely in children.

What causes restrictive cardiomyopathy?

Restrictive cardiomyopathy usually results from an underlying condition that affects the rest of the body. However, the cause is unknown (idiopathic) in some cases. Restrictive cardiomyopathy does not appear to be inherited, but some of the diseases that lead to the condition may be genetic.

Conditions that may be associated with the development of restrictive cardiomyopathy include:

• Scleroderma: A chronic, degenerative disease that affects the joints, skin and internal organs.
• Amyloidosis: A rare disease that 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 been associated with restrictive cardiomyopathy.

What are symptoms of restrictive cardiomyopathy?

Symptoms of restrictive cardiomyopathy may include:

• Shortness of breath after exertion
• Chest pain
• Weakness
• Swelling of the extremities
• Exercise intolerance
• Heart failure

How is restrictive cardiomyopathy treated?

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 from forming.
• Regulate irregular heartbeats.

If surgery is recommended, it may include:

• Pacemaker or defibrillator insertion
• Heart transplant

Talk to your child’s healthcare provider for more information about his specific outlook.

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease and affects 1 in 500 people. The disease sometimes runs in families and is the leading cause of sudden cardiac arrest in kids, particularly during and immediately following exercise. If your child has HCM, it means that his heart's ability to pump blood effectively has been reduced, and he will need comprehensive care and monitoring as he grows.

What causes HCM?

HCM is most often caused by abnormal genes (DNA) in your child's heart muscle that cause the walls of his heart chamber (left ventricle) to become thicker than normal and can impede the blood from leaving the heart, in addition to causing certain types of arrhythmias. 

What are symptoms of HCM?

Signs that your child may have HCM could include one or more of the following:

• Chest pain that occurs most often during exercise
• Fainting, especially after exercise or exertion
• Heart murmur
• Exercise intolerance
• Wheezing or coughing during exercise

How is HCM treated?

The Hypertrophic Cardiomyopathy Program at the Children’s Healthcare of Atlanta Heart Center provides an individualized treatment plan for your child. We provide comprehensive services, including:

• Echocardiogram
• EKG
• Exercise testing and stress echocardiography
• Specialized cardiac MRI
• Extended ambulatory ECG monitoring
• Lab work
• Comprehensive genetic counseling and genetic testing
• Physical examination
• Implantation and monitoring of implanted cardiac devices, including pacemakers and ICDs
• Surgery to remove parts of the muscle that may be impeding blood flow

If a genetic case is identified, our team provides genetic screening to determine if other family members are at risk for developing the disease. And if adult family members are determined to be at risk, or are diagnosed, our team will coordinate care with an adult provider in your community who is specialized in caring for adults with HCM.

What is the Hypertrophic Cardiomyopathy Program at the Children's Heart Center?

• Cardiologists specializing in HCM and stress echocardiography
• Cardiologist specializing in cardiac MRIs
• Cardiac genetic counselors who evaluate your family history
• Nurses and sonographers who perform echocardiograms
• Pediatric cardiothoracic surgeons with expertise in ventricular septal reduction surgeries
• Seamless integration with the adult hypertrophic cardiomyopathy clinic at the Emory University School of Medicine to provide a smooth transition from pediatric to adult care at 21 years of age.

• Arene Butto, MD
• Paul Chai, MD, Chief of Cardiothoracic Surgery and Co-Chief of the Heart Center
• Peter Fischbach, MD
• William Mahle, MD
• Chad Mao, MD
• Robert Whitehill, MD
• Jessica Posey, MSN, FNP-C
• Patricia Simpson, MSN, FNP-C, RN
• Erin Demo, MS, CGC
• Linda Knight, MS, CGC