What is cardiomyopathy?
Cardiomyopathy is a disease of the heart muscle which impairs the heart's ability to pump blood to the rest of the body. Children with cardiomyopathy usually have a normal heart structure, but have a disease that is either primary (in the heart itself) or secondary (affecting the heart as a result of a toxin or infection in the body).
There are three types of cardiomyopathy:
1. Dilated cardiomyopathy: This is the most common type. It is characterized by an enlargement of the main pumping chamber of the heart and a weakened, thin heart muscle. Dilated cardiomyopathy can cause congestive heart failure (an inability of the heart to pump blood normally), abnormal heart rhythms, electrical disturbances in the heart, and the formation of blood clots.
2. Hypertrophic cardiomyopathy: This type of cardiomyopathy causes thickening in the wall separating the chambers of the heart. This thickening can obstruct blood flow, cause a leaky heart valve, and result in irregular heart rhythms. Hypertrophic cardiomyopathy is also known as idiopathic hypertrophic subaortic stenosis (IHSS) or asymmetric septal hypertrophy (ASH).
3. Restrictive cardiomyopathy: This is the least common type of cardiomyopathy in children. It is characterized by an inflexible heart muscle that does not allow blood to fill the pumping chambers normally in between heartbeats.
What causes cardiomyopathy?
In many cases, the exact cause of cardiomyopathy is unknown and the disease cannot be prevented. However, one common cause of cardiomyopathy is myocarditis, a viral infection of the heart that weakens the heart muscle. Some other conditions or factors that may contribute to the development of cardiomyopathy are:
- Viral infections
- Metabolic disorders (such as thyroid disease or diabetes)
- Heart valve problems or heart tissue damage
- Nutritional deficiency
- Abuse of alcohol, cocaine or antidepressant medications
- Certain toxins or chemotherapy drugs used to treat cancer
Additionally, if your child has Barth syndrome, an uncommon genetic disorder, it may cause dilated cardiomyopathy—usually in male children and in the first year of life. In these cases, the condition may be associated with skeletal muscle changes, short stature, an increased chance of bacterial infection, and a decrease in the white blood cells that fight illness.
Cardiomyopathy may be hereditary, and children with cardiomyopathy often have a parent or sibling with the disease, even if no symptoms are present.
What are the signs and symptoms of cardiomyopathy?
The symptoms of cardiomyopathy vary for each child, but may include:
- Dizziness, lightheadedness or fainting
- Difficulty breathing (especially with exertion)
- Swelling in the hands and feet
- Fatigue and irritability
- Pale, cool, or sweaty skin
- Dangerous heart rhythms that can cause fainting or cardiac arrest
Signs and symptoms tend to progress over time. Symptoms may progress quickly or they may level off for a period of time before progressing further. In some cases, a child with cardiomyopathy may show no symptoms at all in the early stage of the disease.
How is cardiomyopathy diagnosed?
A clear diagnosis is the first step to treatment. A pediatric cardiologist (a children's heart doctor) can use several tests to confirm your child's diagnosis. These tests may include:
- Chest X-ray: A beam of electromagnetic energy creates images on film that show the inside structures of your baby's body. A chest X-ray doesn't provide a definitive diagnosis, but it helps the doctor determine your baby's heart size and structure.
- Electrocardiogram (ECG or EKG): This test, conducted by attaching patches with wires (electrodes) to the baby's skin, records the heart's electrical activity. It will show if there are abnormal heart rhythms (arrhythmias or dysrhythmias) and heart muscle stress.
- Echocardiogram: (Echo): This test uses high-pitched sound waves to produce a moving image of the heart on a video screen. It is similar to an ultrasound, and can be used to assess the structure and position of the parts of the heart, as well as related heart defects.
- Cardiac catheterization: During this procedure, your doctor inserts a thin flexible tube (a catheter) into a blood vessel in the groin, then guides it up to the inside of the heart. A dye may be injected through the catheter to make your baby's heart structures visible on X-ray pictures. The catheter also measures blood pressure and oxygen levels.
- Biopsy: A biopsy means that a tiny sample of heart tissue is taken for laboratory analysis.
- Blood tests: Blood tests can reveal the levels of iron, or of a protein called brain natriuretic peptide (BNP), which may be higher if your child's heart is weakened.
How is cardiomyopathy treated?
Once diagnosed, your child's specific treatment may vary, depending on his or her individual needs and on the type of cardiomyopathy that is diagnosed:
- If your child has dilated cardiomyopathy, the doctor may prescribe medications to regulate and improve the heart's pumping ability, prevent clots, and reduce fluid retention and inflammation. In some cases, a pacemaker or an implantable cardioverter-defibrillator (ICD) may be surgically placed in the chest to monitor and control an irregular heartbeat. Cardiac transplantation is needed in some cases.
- If your child has hypertrophic cardiomyopathy, the doctor may prescribe medications to relax and stabilize heart function. In some cases, a pacemaker or ICD may be recommended. Surgery, catheter techniques and pacing therapies may be suggested to reduce the thickened heart wall and restore unobstructed blood flow. Cardiac transplantation is needed in some cases.
- If your child has restrictive cardiomyopathy, the doctor may prescribe medications to reduce fluid retention, lower blood pressure, and regulate the heartbeat. In some cases, the doctor may discuss the option of a heart or lung tansplant.
The outlook for children with cardiomyopathy varies greatly from case to case, depending on the cause and severity of your child's illness and heart condition. Generally speaking, about one third of cardiomyopathy patients have persistently poor heart function, one third have mild to moderate dysfunction and one third make varying degrees of recovery.
About treatment for cardiomyopathy at Children's
Cardiomyopathy is treated through Children's cardiovascular program one of the largest and oldest pediatric cardiovascular programs in the region. Team members consistently achieve treatment results that are among the best in the nation. Each year, care is provided for thousands of the region¹s sickest children with heart conditions, including fetuses, newborns, infants, children, adolescents, and adult, long-term patients with pediatric cardiovascular conditions.
For more information, please call Children's Heart Clinic at 1-800-938-0301.