Pediatric reference values for myocardial contraction fraction and global function index of the left ventricle: A cardiovascular magnetic resonance study

Abstract

BackgroundCardiovascular magnetic resonance (CMR) derived global function index (GFI) and myocardial contraction fraction (MCF) were identified as useful imaging markers to assess left ventricular (LV) cardiac performance and can provide prognostic information for several cardiac diseases. As pediatric reference values are lacking, the aim of this retrospective study was to establish these values. Methods154 CMR examinations of healthy children and adolescents (4–18 years) were included. LV end-diastolic, end-systolic and stroke volumes, ejection fraction (LVEF) and myocardial mass were measured using short axis stacks. Results were used to calculate LVGFI and LVMCF. Statistically, the Lambda-Mu-Sigma (LMS)-method was applied to create percentile curves and tables. ResultsThe mean age (standard deviation) of the subjects was 13.8 (2.8) years, 102 were male (66%). Mean LVGFI was 46.3 (6.0)% and mean LVMCF was 110.6 (19.9) %. Both, LVGFI and LVMCF decreased significantly with age (LVGFI: r = −0.30, p < 0.001; LVMCF: −0.30, p < 0.001). There was no statistical difference between girls and boys (p all >0.05). Strong correlations between LVGFI and LVMCF (r = 0.78, p < 0.001) as well as between LVGFI and LVEF (r = 0.80, p < 0.001) were documented whereas the correlation of LVMCF and LVEF was weaker (r = 0.32, p < 0.001). Univariable and multivariable regression analysis demonstrated that LVGFI was strongly associated with age whereas LVMCF was associated with weight. Percentile curves and tables were created accordingly. ConclusionWe provide pediatric CMR reference values for the new cardiac functional markers LVGFI and LVMCF. These may improve the interpretation of clinical CMR studies and can be used for future research studies.