Normal Ranges of Global Left Ventricular Myocardial Work Indices in Adults: A Meta-Analysis

Abstract Background Recent studies have demonstrated left ventricular myocardial work (MW) is incremental in diagnosis and prognostication when compared to left ventricular ejection fraction and myocardial strain. We performed a meta-analysis of normal ranges of non-invasive MW indices including global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) and to determine confounder that may contribute to variance in reported values. Methods Four databases including Pubmed, Scopus, Embase, and Cochrane Library were searched through January 2021 using the key terms “myocardial work", "global constructive work", "global wasted work", “global work index", "global work efficiency”. Studies were included if the articles reported LV myocardial work using 2D transthoracic echocardiography in healthy normal subjects, either in control group or comprising of the entire study cohort. The weighted mean was estimated by using the random effect model with a 95% confidence interval. Heterogeneity across included studies was assessed using the I2 test. Funnel plot and Egger’s regression test were used to assess potential publication bias Results The search yielded 476 articles. After abstract and full-text screening, we included 13 datasets with 1665 patients for the meta-analysis. The reported normal mean values of GWI and GCW among the studies were 2010 mmHg% (95% CI, 1907 to 2113), and 2278 mmHg% (95% CI, 2186 to 2369) respectively. The mean GWW was 80 mmHg% (95% CI, 73 to 87), and the mean GWE was 96.0% (95% CI, 96% to 96%). Furthermore, gender significantly contributed to variations in normal values of GWI, GWW, and GWE. No evidence of significant publication bias was observed. Conclusion In this meta-analysis, we provide echocardiographic reference ranges for non-invasive indices of MW. These normal values could be served as a reference for clinical and research use.