2.3 Statistical analyses
To evaluate the change in LVEF and QRS duration over time, means,
standard deviations, and sample sizes were extracted from articles to
estimate the overall average values and confidence intervals (CIs).
Statistical heterogeneity was conducted by calculating Higgins
I2; I2 >50% was
considered to indicate significant heterogeneity.22After confirming heterogeneity, we used a random effects model because
the populations included in the individual studies were from different
populations.23 Potential publication bias was assessed
by visual inspection of the funnel plot and the Egger regression
asymmetry test. If the P for bias was >0.05, it was judged
that there was no publication bias.24 All tests with
P-values <0.05 were considered to be statistically
significant. Statistical analyses were performed using R programming
version 4.0.3 (The R Foundation for Statistical Computing, Vienna,
Austria).