Cardiomyopathy in Children and Adolescents
Cardiomyopathy is a very general term that means only that there is a problem with the muscle of the heart. There are many different types of cardiomyopathy. Although most people with CM have either dilated cardiomyopathy or hypertrophic cardiomyopathy, there are other very rare types of CM including ischemic CM (related to coronary artery disease and heart attacks), peripartum CM (following childbirth), restrictive CM (caused by stiff heart muscle making the heart difficult to fill), and arrhythmogenic right ventricle (a very thin right pumping chamber associated with irregular heart rhythms). For the more rare types of CM, please check the links listed below.
Dilated cardiomyopathy (DCM) is a disorder in which the heart muscle is weak and thin, and the heart is quite enlarged. About half the time no cause is identified for DCM, and in most other cases it is thought to be the result of a prior virus infection. Some rare disorders of the metabolism can also result in DCM, such as carnatine deficiency and muscular dystrophy. DCM does not generally run in families. The heart can become quite enlarged in DCM. If CM is severe enough, heart can become quite enlarged. In advanced cases, a patient can develop a syndrome called "congestive heart failure". Signs and symptoms of CHF can include poor exercise tolerance, shortness of breath, poor feeding and poor weight gain, or even weight loss. In addition, the liver can become enlarged and there can be swelling of the legs, feet or other areas (edema). Advanced CHF can lead to dizziness, fainting or even death. DCM can also be associated with abnormal rhythms of the heart, resulting in palpitations or even sudden death. Medications are often used for patients with CHF to relieve symptoms, and in advanced cases heart transplant may even be necessary.
Hypertrophic cardiomyopathy (HCM) is a disorder in which the heart muscle is very thick, and can even create tight areas that make it hard for the heart to pump the blood out to the body (subaortic stenosis). Other names for HCM include "idiopathic hypertrophic subaortic stenosis (IHSS) and hypertrophic obstructive cardiomyopathy (HOCM). Most cases of HCM are inherited from an affected parent (autosomal dominant inheritance), although in many cases it occurs randomly when neither parent is affected. HCM can be treated with medications (which are very different from those used in DCM), and there is some evidence that medical treatment, particularly with a type of medication called "calcium channel blockers", may slow the progression of the disease. There are also surgical procedures to relieve the subaortic stenosis. Patients with HCM may also develop CHF and are at risk of sudden death, presumably because of irregular heart rhythms. It is sometimes necessary to consider heart transplant, or implantation of a device to protect against irregular heart rhythms (defibrillator). Children of a parent with HCM are at risk to develop the disease as they get older, and should be screened about every three years. Although there is some understanding of the genetics of HCM, there are not yet easy tests that will consistently show whether a child is at risk of developing HCM later in life.
Any patient who is interested in pursuing the possibility of genetic testing for HCM could contact one of the researchers doing work in this area. I can recommend:
Dr. Christine Seidman, MD
Department of Genetics
Harvard Medical School
Alpert Room 533
200 Longwood Avenue
Boston, MA 02115
Please have a look as some of the web sites below. As always with the web, consider who wrote the material before you take it too seriously.
Information about cardiomyopathy
Hypertrophic cardiomyopathy (including IHSS and HOCM)
Arrhythmogenic right ventricle cardiomyopathy