Cardiomyopathy is not a single, isolated disease; it’s a term used to classify several separate diseases that affect the heart muscle. The primary forms of cardiomyopathy are:
- dilated cardiomyopathy, also called congestive cardiomyopathy. This is the most common type and occurs when the main pumping chamber of the child’s heart muscle becomes too dilated or “stretched out.” Dilated cardiomyopathy renders the heart unable to pump blood effectively.
- hypertrophic cardiomyopathy, also called hypertrophic obstructive cardiomyopathy, asymmetric septal hypertrophy or idiopathic hypertrophic subaortic stenosis. All of these names describe the same problem: Unlike dilated cardiomyopathy, which makes the heart muscle stretched out, hypertrophic cardiomyopathy makes the heart muscle too thick. Usually, the thickening occurs in the muscle of the left ventricle in the heart, often involving the wall between the heart’s two ventricles.
- arrhythmogenic right ventricular cardiomyopathy, also called arrhythmogenic right ventricular dysplasia, is a rare form of cardiomyopathy that affects only one in 5,000 people. This type of cardiomyopathy occurs when the muscle of the heart’s right ventricle is replaced by thick or fatty scar tissue. The scarring “scrambles” electrical signals within the heart and can impair the heart’s ability to pump blood.
- A fourth, rare type of cardiomyopathy is restrictive cardiomyopathy, which causes the heart muscle to become excessively rigid or stiff. This makes it difficult for the ventricles of the heart to properly fill with blood.
Other facts about cardiomyopathy you may not have known:
- Some forms of cardiomyopathy run in families.
- 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 need a heart transplant to manage their cardiomyopathy.
What causes dilated cardiomyopathy?
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
- substance abuse
- thyroid disease
What causes hypertrophic cardiomyopathy?
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.
What causes arrhythmogenic right ventricular cardiomyopathy?
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.
What causes restrictive cardiomyopathy?
Causes of restrictive cardiomyopathy may include:
- chemotherapy treatments for certain cancers
- radiation treatments to the chest for certain cancers
- 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.
Signs and symptoms
What are the symptoms of dilated cardiomyopathy?
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
What are the symptoms of hypertrophic cardiomyopathy?
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
What are the symptoms of arrhythmogenic right ventricular cardiomyopathy?
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
- light-headedness or dizziness
- “racing” heartbeat
- shortness of breath
- swelling in the abdomen
- swelling in the legs
What are the symptoms of restrictive cardiomyopathy?
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:
- 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
Q: Will my child be OK?
A: Cardiomyopathy is very often a “time will tell” disease; every child has different circumstances, and in each case, the progression of the disease can be unpredictable. Your child’s course of treatment and long-term outlook will depend greatly upon:
- his age
- the severity of the disease at the time of diagnosis
- his tolerance for specific medications or procedures
- your family’s preferences for treatment
Q: What makes cardiomyopathy different from other heart diseases?
A: Unlike other forms of heart disease, cardiomyopathy:
- can occur at the same time as other diseases that affect other parts of the body—not just the heart
- commonly affects children, adolescents and young adults—not just older people
- can be progressive, meaning symptoms worsen over time
- can run in families
- is relatively rare, affecting about 50,000 Americans of all ages at any given time
- may necessitate a heart transplant
Q: Does my child have to cut back on physical activities?
A: Whether your child needs to cut back significantly on activities—or cut back at all—depends greatly on the type of cardiomyopathy she has and her circumstances and symptoms:
Children with dilated cardiomyopathy generally do not have to restrict their physical exercise, although older children involved in certain sports (especially high-impact sports) may not be able to perform at their prior level of competition. Symptoms usually dictate a child’s ability to participate in physical activities. Your child’s treating clinician must make a specific determination as to which, and to what extent, activities are allowed.
Children with hypertrophic cardiomyopathy often need to restrict their physical activities—including sports. Your child’s treating clinician must make a specific determination as to which, and to what extent, activities are allowed.
In general, children with arrhythmogenic right ventricular cardiomyopathy should not engage in strenuous exercise. Your child’s treating clinician will evaluate her individual situation and inform you how much, and which types of, exercise is acceptable.
Children with restrictive cardiomyopathy may need to curtail or stop certain physical activities. Your child’s treating clinician should make the determination about which—and to what extent—physical exertion is allowed.
Q: Can changes to my child’s diet help manage his cardiomyopathy?
A: While diet changes should not be considered substitutes for more involved medical care, children with cardiomyopathy—particularly the restrictive form—can benefit from maintaining a healthy weight and restricting their salt and caffeine intake. Your treating clinician can give you more specific recommendations.
Q: Can some cancer treatments cause cardiomyopathy?
A: It’s an unfortunate fact that many of the chemotherapy agents that are so beneficial in treating childhood cancers have long-term side effects. Certain chemotherapy drugs—particularly a class of drugs called anthracyclines—have been linked to later development of cardiomyopathy, while restrictive cardiomyopathy has been tied to radiation treatments of the chest for some cancers.
Nonetheless, many children undergoing chemotherapy or radiation treatment do not develop cardiomyopathy.
Q: What do I need to look out for once my child has been diagnosed with cardiomyopathy?
A: Parents of children with cardiomyopathy should always be watchful of changes in behavior, appearance, appetite, activity level and respiration.
You should seek medical help immediately if your child experiences any of the following:
- chest pain
- clammy skin or the feeling of a “cold sweat”
- heart palpitations
- irregular heartbeat
- pale, ashen color in the face
- racing heartbeat
- rapid breathing
- shallow breathing
- shortness of breath
- swollen feet, ankles or legs
Q: Does Boston Children’s offer genetic testing for cardiomyopathy?
A: Yes, Boston Children’s Cardiovascular Genetics Program provides several clinical services to test for heart conditions including cardiomyopathy. The program also offers genetic counseling.
Q: Will my child need a heart transplant?
A: While a heart transplant may become a necessary treatment option for some children with any of the common forms of cardiomyopathy, not every child with cardiomyopathy will need one.
Q: Is there a cure for cardiomyopathy?
A: Unfortunately, cardiomyopathy is a chronic condition. There is no treatment that can cure the disease in any of its forms, nor guarantee long-term recovery.
Depending upon how advanced the disease is at the time of diagnosis, some degree of heart function may be irreversibly lost. The good news is that, when diagnosed early, many forms of cardiomyopathy respond very well to long-term medication use, pacemaker or defibrillator implantation or heart transplant.
Questions to ask your doctor
You and your family play an essential role in your child’s treatment for cardiomyopathy. It’s important that you share your observations and ideas with your child’s treating physician, and that you have all the information you need to fully understand the treatment team’s explanations and recommendations.
You’ve probably thought of many questions to ask about your child’s cardiomyopathy. It’s often very helpful to jot down your thoughts and questions ahead of time and bring them with you, along with a notebook, to your child’s appointment. That way, you will have all of your questions in front of you when you meet with your child’s treating clinician and can make notes to take home with you. (If your child is old enough, you can encourage him or her to write down questions, too.)
Initial questions to ask your doctor might include:
- What type of cardiomyopathy does my child have?
- How did you arrive at this diagnosis?
- Are there any other conditions my child might have instead?
- Does my child require further testing or procedures?
- What is my child’s prognosis?
- What medications will you prescribe?
- What are the possible side effects of these medications?
- Will my child need a pacemaker or defibrillator?
- Will my child need surgery or a heart transplant?
- What role should I play in my child’s treatment?
- How should I talk to my child about this condition and the long-term outlook?
- How should I explain my child’s condition to others?
- Do I need to restrict my child’s physical activity?
- Do I need to make any other changes to my child’s home and school routines?
- What other resources can you point me to for more information?