Cardiomyopathy | Symptoms & Causes

What are the symptoms of cardiomyopathy?

Some children with cardiomyopathy have few to no signs of illness at first, while others may be seriously affected by shortness of breath, dizziness and other symptoms shortly after birth.

Dilated cardiomyopathy symptoms

Many children with dilated cardiomyopathy (DCM) don’t have any symptoms. Those who do may have one or more of the following symptoms, which may vary depending on the age of the child:

  • abdominal pain
  • chest pain
  • chronic fatigue
  • chronic loss of appetite or inability to feed
  • frequent irritability without a visible cause
  • frequent vomiting
  • pale or clammy skin
  • rapid breathing
  • rapid or “racing” heartbeat
  • shortness of breath
  • slow or delayed growth

Hypertrophic cardiomyopathy symptoms

Children with hypertrophic cardiomyopathy (HCM) may have symptoms during physical activity, or their symptoms may come on suddenly and unpredictably. Common symptoms signs include:

  • abnormal heart rhythm
  • chest pain
  • dizziness
  • fainting

Restrictive cardiomyopathy symptoms

Symptoms of restrictive cardiomyopathy can vary greatly from child to child. Many children have no noticeable symptoms, others have very mild symptoms, while others have clear warning signs that become progressively worse if the disease is not treated.

Symptoms can include:

  • fatigue
  • persistent coughing
  • shortness of breath during exercise or right after exercise
  • shortness of breath at night (while resting or sleeping)
  • shortness of breath while lying flat
  • swelling in the abdomen
  • swelling in the feet or ankles
  • poor growth or failure to gain weight

Arrhythmogenic right ventricular cardiomyopathy symptoms

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is often difficult to diagnose because many people never have symptoms or develop symptoms suddenly after not having any problems.

Symptoms can include:

  • abnormal heart rhythm
  • fainting
  • lightheadedness or dizziness
  • racing heartbeat
  • shortness of breath
  • swelling in the abdomen
  • swelling in the legs

What are the causes of cardiomyopathy?

Some forms of cardiomyopathy run in families. Anyone with a family history of cardiomyopathy, heart attack or arrhythmias should be screened. Genetic testing can detect about 50 about percent of cases. In other cases, cardiomyopathy develops because of another medical condition. In many cases, however, there is no clear cause for cardiomyopathy (idiopathic cardiomyopathy).

Dilated cardiomyopathy causes

In many cases, DCM occurs without a known reason.

When the cause can be determined, reasons include:

  • myocarditis, an inflammation of the heart muscle that usually stems from a
  • viral infection
  • certain metabolic diseases
  • certain genetic disorders, like muscular dystrophy
  • inheriting the condition from a parent

Some less common causes of DCM are:

  • connective tissue disorders, such as rheumatoid arthritis
  • coronary artery disease
  • diabetes that is not properly controlled
  • obesity
  • substance abuse
  • thyroid disease

Hypertrophic cardiomyopathy causes

Hypertrophic cardiomyopathy (HCM) has a strong inherited component. At least half of all children with HCM have a parent or sibling with some enlargement in their heart muscle, although these family members may not have any symptoms themselves.

HCM is caused by a defect in the genes that control the manufacture of the proteins of the heart muscle.

Restrictive cardiomyopathy causes

Restrictive cardiomyopathy is not typically inherited, and many children have no identifiable cause for their disease.

When there is known cause, these may include:

  • chemotherapy treatments for certain cancers
  • radiation treatments to the chest for certain cancers
  • sarcoidosis
  • scleroderma
  • diseases of the heart lining, including endomyocardial fibrosis and Loeffler’s
  • syndrome
  • too much iron in the heart (hemochromatosis)
  • an abnormal protein buildup in the muscle of the heart (amyloidosis) 
  • tumors in the heart
  • a buildup of scar tissue in the heart

Arrhythmogenic right ventricular cardiomyopathy causes

ARVC often runs in families. At least 30 to 50 percent of all people with ARVC have family members with the disease. Researchers are working to identify precisely which gene mutations and chromosomes are involved in the onset of ARVC.