Development and Progression of Left Ventricular Hypertrophy in Children with Hypertrophic Cardiomyopathy

Abstract

Whether the magnitude and distribution of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy are established at birth, or whether they evolve during the first years of life, is unknown. Accordingly, we conducted serial echocardiographic studies in 39 children with a family history or morphologic evidence of hypertrophic cardiomyopathy. The patients were initially evaluated at 4 to 15 years of age (mean, 11) and most recently at 9 to 20 years (mean, 16). During a follow-up period of 2.5 to 6.8 years (mean, 4), the magnitude and extent of preexisting left ventricular hypertrophy markedly increased in 17 patients and the morphologic appearance of the heart evolved from normal to hypertrophic in 5 others. In these 22 patients the left ventricular wall thickness increased strikingly (by 6 to 23 mm, a change of 101±62 percent); these increases significantly exceeded those expected as a consequence of normal growth (13±10 percent; P<0.001) and were not associated with symptomatic deterioration or related to subaortic obstruction.