WHAT IS RESTRICTIVE CARDIOMYOPATHY (RCM)?
With RCM, the walls of the lower chambers of the heart (ventricles) are abnormally stiff but not necessarily thickened or enlarged. The heart’s rigid walls fail to relax and expand adequately, “restricting” the ability of the heart to fill with blood. While the heart pumps normally, it is still unable to supply enough blood to the body. This puts pressure on the upper chambers of the heart (atria), and they become enlarged and out of proportion to the size of the lower chambers of the heart (ventricles). In advanced stages of the disease, the heart may not pump blood efficiently and blood may back up into the liver and lungs as a result of congestive heart failure.
Cardiomyopathy is nondiscriminatory in that it can affect any adult or child at any stage of their life. It is not gender, geographic, race or age specific. It is a particularly rare disease when diagnosed in infants and young children. A diagnosis at a young age usually, but not always, signifies a serious heart condition that requires aggressive treatment. The concern lies in the uncertainty of how the heart muscle will respond with each additional growth spurt. In severe cases, small children may experience progressive symptoms quickly leading to heart failure. Cardiomyopathy continues to be the #1 reason for heart transplants in children.
Currently there are no published reports specifying the total number of children affected but it is roughly estimated to be in the hundreds of thousands when all forms of cardiomyopathy are taken into account. According to the national pediatric cardiomyopathy registry, 1 in every 100,000 children in the U.S. under the age of 18 is diagnosed with primary cardiomyopathy. This annual incidence rate, however, is extremely conservative. This number excludes the increasing number of children with secondary cardiomyopathy and the large pool of undiagnosed, asymptomatic cases.
Restrictive cardiomyopathy (RCM) is less common affecting 3 to 5 percent of children with cardiomyopathy. According to the Pediatric Cardio- myopathy Registry, RCM occurs at a rate of less than 1 per million children.
There are numerous causes for a complex disease such as cardiomyopathy. For the majority of diagnosed children, the exact cause remains unknown (termed “idiopathic”). In some cases, it may be related to an inherited condition such as a family history of cardiomyopathy or a genetic disorder such as fatty acid oxidation, Barth syndrome, or Noonan syndrome.