Cardiomyopathy | Symptoms and Causes

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Some forms of cardiomyopathy run in families. Anyone with a family history of cardiomyopathy, heart attack, or arrhythmias should be screened. Today, genetic testing can detect 50 percent of cases. Other times, cardiomyopathy develops because of another medical condition (like undergoing chemotherapy for certain childhood cancers). In many cases, however, there is no clear cause for a child’s cardiomyopathy.

Some children with cardiomyopathy display few to no signs of illness at first, while others may be seriously affected by shortness of breath, dizziness and other symptoms from the beginning. Sometimes, children with cardiomyopathy need a heart transplant. Cardiomyopathy is the No. 1 reason for heart transplants in children. 

Dilated cardiomyopathy symptoms

Many children with dilated cardiomyopathy do not display symptoms; the disease is sometimes diagnosed coincidentally—for example, when the child has an echocardiogram for another reason, such as a heart murmur.

However, when symptoms do emerge, they may include one or more of the following:

  • abdominal pain
  • chest pain
  • chronic fatigue
  • chronic loss of appetite
  • 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

Dilated cardiomyopathy causes

It’s important to note that in many cases, dilated cardiomyopathy occurs without a known reason. If your child’s disease has no identifiable cause, it is called an idiopathic dilated cardiomyopathy.

When the cause can be determined, reasons include:

  • prior 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 dilated cardiomyopathy are:

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

Hypertrophic cardiomyopathy symptoms

Children with hypertrophic cardiomyopathy may experience symptoms during physical exertion, but their symptoms can also come on suddenly and unpredictably. Common warning signs include:

  • abnormal heart rhythm
  • chest pain
  • dizziness
  • fainting

Early detection can widen treatment options significantly, especially medical treatment options.

Hypertrophic cardiomyopathy symptoms

Hypertrophic cardiomyopathy has a strong inherited component. At least half of all children with this form of the disease have a parent or sibling with some degree of enlargement in their heart muscle, although these family members may not experience any symptoms themselves.

Hypertrophic cardiomyopathy results from a defect in the genes that control the manufacture of the proteins of the heart muscle.

Arrhythmogenic right ventricular cardiomyopathy symptoms

Arrhythmogenic right ventricular cardiomyopathy is often difficult to diagnose because many people never display warning signs, and can function with almost no disruption to their daily activities unless or until they have an acute onset of symptoms.

A person will usually show clear signs of having the condition when they are young (either as children, as teens or as adults under the age of 40). Commonly, the diagnosis is made by cardiovascular magnetic resonance imaging (MRI).

When symptoms are noticeable, they can include:

  • abnormal heart rhythm
  • fainting
  • light-headedness or dizziness
  • “racing” heartbeat
  • shortness of breath
  • swelling in the abdomen
  • swelling in the legs

Arrhythmogenic right ventricular cardiomyopathy causes

Arrhythmogenic right ventricular cardiomyopathy frequently runs in families. At least 30 to 50 percent of all people with this form of cardiomyopathy also have family members with the disease. Researchers are working to identify precisely which gene mutations and chromosomes are involved in the onset of arrhythmogenic right ventricular cardiomyopathy.

Restrictive cardiomyopathy symptoms

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

When they are noticeable, restrictive cardiomyopathy symptoms can include:

  • fatigue
  • persistent coughing
  • shortness of breath while or immediately after exercising
  • 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

Restrictive cardiomyopathy causes

Causes of restrictive cardiomyopathy 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 the very rare Loeffler’s syndrome
  • too much iron in the heart—this is known as hemochromatosis
  • an abnormal protein buildup, called amyloidosis, in the muscle of the heart
  • tumors in the heart
  • a buildup of scar tissue in the heart for any reason

Restrictive cardiomyopathy is not typically inherited. Many children have what is called idiopathic restrictive cardiomyopathy, meaning there is no identifiable cause for their disease.

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