Hypertrophic Cardiomyopathy
Hypertrophic Cardiomyopathy (HCM)Also known as hypertrophic obstructive cardiomyopathy (HOCM), idiopathic hypertrophic subaortic stenosis (IHSS) and asymmetrical septal hypertrophy (ASH), non-obstructive hypertrophic cardiomyopathy (HCM)
The second most common form of heart muscle disease is hypertrophic cardiomyopathy. This disease is characterized by the abnormal growth and arrangement of muscle fibers in the heart (myocardial disarray), leading to excessive thickening of the heart walls. Typically, the portion of muscle mass that is thickest is in the heart's main pumping chamber (left ventricle) with the muscle wall that separates the heart's chambers (septum) affected most often. This condition is referred to as asymmetric septal hypertrophy. Although this is the more common form, the distribution of muscle thickness (hypertrophy), location, and degree of wall thickness may vary greatly among patients. Other forms of hypertrophy are symmetric ventricular hypertrophy (thickening is evenly distributed throughout the ventricle including the septum and wall) and apical hypertrophy (thickening is localized at the bottom portion of the heart).
In all three cases, the thickening of the muscle walls cause the heart chamber to be stiffer and smaller, making it difficult for blood to flow into and out of the heart effectively. This hypertrophy or thickening can progress to severe problems with obstruction of blood flow and relaxation of the left ventricle. Children with HCM are also at an increased risk of arrhythmias and sudden cardiac arrest. In advanced HCM (seen in less than 10% of patients), the disease may progress to a "dilated" form of cardiomyopathy where the heart muscle stretches to compensate for the enlarged muscle wall and poor pumping action.
HCM affects up to 500,000 people in the U.S. with children under 12 accounting for less than 10% of all cases. According to the Pediatric Cardiomyopathy Registry, HCM occurs at a rate of 5 per million children. The cause of HCM is largely unknown but most cases appear to be genetic in origin
The second most common form of heart muscle disease is hypertrophic cardiomyopathy. This disease is characterized by the abnormal growth and arrangement of muscle fibers in the heart (myocardial disarray), leading to excessive thickening of the heart walls. Typically, the portion of muscle mass that is thickest is in the heart's main pumping chamber (left ventricle) with the muscle wall that separates the heart's chambers (septum) affected most often. This condition is referred to as asymmetric septal hypertrophy. Although this is the more common form, the distribution of muscle thickness (hypertrophy), location, and degree of wall thickness may vary greatly among patients. Other forms of hypertrophy are symmetric ventricular hypertrophy (thickening is evenly distributed throughout the ventricle including the septum and wall) and apical hypertrophy (thickening is localized at the bottom portion of the heart).
In all three cases, the thickening of the muscle walls cause the heart chamber to be stiffer and smaller, making it difficult for blood to flow into and out of the heart effectively. This hypertrophy or thickening can progress to severe problems with obstruction of blood flow and relaxation of the left ventricle. Children with HCM are also at an increased risk of arrhythmias and sudden cardiac arrest. In advanced HCM (seen in less than 10% of patients), the disease may progress to a "dilated" form of cardiomyopathy where the heart muscle stretches to compensate for the enlarged muscle wall and poor pumping action.
HCM affects up to 500,000 people in the U.S. with children under 12 accounting for less than 10% of all cases. According to the Pediatric Cardiomyopathy Registry, HCM occurs at a rate of 5 per million children. The cause of HCM is largely unknown but most cases appear to be genetic in origin
