Echocardiographic reference ranges of myocardial work in children and adolescents: A meta-analysis

Background: Establishing reference values for LV myocardial work (MW) is essential before its widespread implementation in pediatrics. This study aims to provide normal LV MW ranges, encompassing global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Methods: Databases were searched through February 1st, 2024, for studies reporting MW indices in healthy children across pediatric age categories. Weighted means were obtained from random-effect models with corresponding 95 % confidence intervals (CI). Subgroup analyses were conducted to identify sex or geographic differences. Meta-regression analysis was used to identify modulating effects of demographic, clinical, and echocardiographic variables. Results: The search yielded 104 articles, of which, 12 articles with 1037 patients (age 10.7 +/- 0.7 years, 47.5 % female) were eligible for inclusion. The reported normal overall pooled mean values of GWI and GCW were 1525.4 (95 % CI, 1328.1-1722.6) mmHg% and 1880.3 (95 % CI, 1683.6-2077.0) mmHg%, respectively. Pooled mean GWW was 57.2 (95 % CI, 51.9-62.5) mmHg%, and pooled mean GWE was 96.8 (95 % CI, 96.6-97.0) %. Subgroup analysis found no sex differences (P > 0.050), but significant regional variations: GCW and GWW differed in European or US cohorts versus East Asian cohorts (P = 0.033 and P = 0.039, respectively). Meta- regression identified age, blood pressure, and heart rate as significant modulators. Pooled inter-observer intraclass correlation coefficients (ICCs) ranged from 0.86 to 0.96, while pooled intra-observer ICCs ranged from 0.81 to 0.93, indicating excellent reproducibility. Conclusions: We provide age-specific MW reference ranges for children, valuable for both clinical and research purposes, and confirm the reproducibility of MW.