Reference values for atrial size and function in children and young adults by cardiac MR: a study of the German competence network congenital heart defects.

PURPOSE: To provide reference data for atrial size and function during childhood and adolescence by cardiac MR (CMR).
MATERIALS AND METHODS: We prospectively examined 115 healthy children and adolescents (mean age, 12.4 ± 4.1 years; range, 4.4-20.3 years) by CMR using a stack of standard two-dimensional steady-state free-precession slices acquisition covering the whole heart in transverse plane. Maximal and minimal volumes of both atria and their respective calculated cyclic volume change (CVC) and emptying fraction (EMF) were determined and reference centile curves were computed (lambda-mu-sigma [LMS]-method).
RESULTS: Gender differences were noted for atrial volumes and derived parameters. Maximal right atrial (RA) volume for girls was 53.3 ± 11.8 mL/m(2) and 58.1 ± 15.7 for boys (P = 0.064), minimal RA volume for girls/boys was 23.2 ± 6.2/27.0 ± 7.9 mL/m(2) (P = 0.004). Maximal left atrial (LA) volume for girls/boys was 44.2 ± 8.7/46.7 ± 10.1 mL/m(2) (P = 0.143) and minimal LA volume for girls/boys was 19.2 ± 3.9/21.5 ± 5.1 mL/m(2) (P = 0.009). For both atria, CVC was higher for boys, but EMF higher for girls. Percentiles of RA/LA volumes showed steeper increase in boys than in girls, who in fact showed a plateau after age 14.
CONCLUSION: Pediatric sex-specific reference centiles are provided to improve clinical interpretation and facilitate future research involving CMR-derived atrial function.