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Meta analysis of left ventricular normal reference value in echocardiographic measurements for racial heterogeneity

Objective 
To investigate the heterogeneity of the left ventricular reference value in echocardiography mesurements by Meta analysis. 
 
 
Methods 
A literature retrieval in PubMed, Embase, Medline and other databases from January 2005 to September 2017 related to left ventricular normal reference value in healthy adults was performed. Cohrane′s Q test was used to test the heterogeneity, and I2 was used as a statistic for the description of heterogeneity. Subgroup analysis, sensitivity analysis and Meta regression were used to analyze the sources of heterogeneity. 
 
 
Results 
The Meta analysis enrolled 9 studies including 5 933 normal cases. The heterogeneity test showed that the left ventricular normal reference value of echocardiography was highly heterogeneous among the studies. In subgroup analysis, some measurements′ heterogeneity were significantly reduced. Meta regression analysis showed that the contribution of racial specificity to heterogeneity was relatively high in some measurements. 
 
 
Conclusions 
The heterogeneity of left ventricle is mainly related to racial specificity, but it cannot fully explain the heterogeneity between studies. Further studies are needed to demonstrate the involved factors of heterogeneity of left ventricular normal reference values. 
 
 
Key words: 
Echocardiography; Ventricular function, left; Reference values; Heterogeneity; Meta-analysis