Frequency and severity of endocardial fibroelastosis in dilated hearts from children—endocardial thickness is inversely correlated to age

Abstract

SummaryDiffuse endocardial thickening in dilated hearts has been considered as a distinct pathological entity, usually being termed endocardial fibroelastosis. It is common in infants and children and rare in adults. Current opinion holds that the endocardial thickening is a non-specific reaction to stress in the ventricular wall. Our personal observations point to the most severe forms occurring in young infants. To determine the frequency and severity of endocardial fibroelastosis in children with dilated cardiomyopathy, we studied 21 necropsy hearts, both grossly and microscopically. Ages of the patients ranged from two to 175 months (mean 46.5, median 23 months). Using a graduated eyepiece, we measured the endocardial thickness in samples from three sites in the left ventricle and one from the right ventricle. The values were compared to those obtained from similar measurements of the endocardium in hearts from four children presenting with tetralogy of Fallot. All the dilated hearts presented some degree of endocardial thickening. The gross detection of fibroelastosis depended on the degree of thickening. There was a negative but linear correlation between age and the mean endocardial thickness (r=0.70; p>0.001). Our findings support the concept that endocardial cells have greater replicative and secretory potentials in young patients, and that endocardial fibroelastosis is a secondary phenomenon in dilated hearts.