Acquired Heart Disease

Cardiomyopathy

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Cardiomyopathy is a form of heart disease in which the heart is abnormally enlarged, thickened and/or stiffened. This impairs the heart's ability to pump blood throughout the body effectively and can sometimes lead to heart failure, irregular heartbeats (called arrhythmias) and blood clots. In children, cardiomyopathy is most common in infants under 1 year old.

There are two general types of cardiomyopathy: ischemic cardiomyopathy, which results from coronary artery disease, and nonischemic cardiomyopathy. All cases of cardiomyopathy in children are considered nonischemic, of which there are four main types:

• Dilated Cardiomyopathy (DCM) -- Also know as congestive cardiomyopathy, this is the most common form of the disease and occurs when heart muscle tissue is stretched and enlarged, making it difficult for the heart to function and often causes congestive heart failure. For the most part, the cause of DCM in children remains unknown. It is sometimes caused by viruses (such as Coxsackie B viruses), certain diseases, severe anemia or nutritional deficiencies, and rare pregnancy complications. Other cases may be genetic in nature.

• Hypertrophic Cardiomyopathy (HCM) -- This is the second most common type of cardiomyopathy and results in excessive thickening of the heart walls. Blood flow is restricted as the heart chambers becomes smaller and stiffer. Most HCM is due to genetic factors.

• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) -- This is a very rare condition, especially in children, where fatty tissue replaces heart muscle. ARVC is thought to be inherited and is usually found in teenagers or young adults.

• Restrictive Cardiomyopathy (RCM) -- This is the least common form of cardiomyopathy and is especially rare in children. RCM affects the ventricles (or lower chambers of the heart), restricting blood flow to the heart. The cause of RCM in children is not known.

Acquired Cardiomyopathy

Although many factors are associated with cardiomyopathy, the exact cause of the disease remains unknown. Many cases are genetic in nature, where the condition is inherited, while others are acquired.

The most common cause of acquired cardiomyopathy is a viral infection called myocarditis, which weakens the heart muscle. Other causes include:

• Infectious diseases
• Diseases that affect the immune system, such as HIV
• Nutritional deficiencies or obesity
• Exposure to toxins such as drugs, alcohol and radiation
• Pregnancy-related complications

Symptoms

Symptoms of cardiomyopathy vary. This is further complicated by the fact that infants and young children are often unable to express how they feel. That said, there are a number of symptoms associated with the different forms of cardiomyopathy:

• Dilated Cardiomyopathy (DCM) -- Symptoms in infants include difficulty breathing, poor appetite and slow weight gain. In addition, older children also may have trouble being physically active and become excessively fatigued when exercising.

• Hypertrophic Cardiomyopathy (HCM) -- Infants with HCM often have trouble breathing, may sweat excessively and have a poor appetite. Older children may have shortness of breath, dizziness and chest pain. They also may faint or have trouble being physically active.

• Restrictive Cardiomyopathy (RCM) -- Although the symptoms of RCM tend to be subtle, some children may have a poor appetite, tire easily, and experience chest pain, an upset stomach and a dry cough.

• Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) -- As stated before, ARVC is very rare in children and symptoms usually are not present until the teen years or later.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007