Statistical analysis:
Descriptive statistics were summarized as mean ± standard deviation or
number with percentage. Statistically relevant correlations between the
Doppler echocardiographic parameters and RVEF by CMR were achieved by
linear regression analysis. Receiver operating characteristics (ROC)
curves were obtained by analyzing the variables of echocardiography as
the sample factors and RVEF by CMR as the state variable. Shapiro-Wilk
test was made use to determine the normal distribution of data, whereas
an analysis of variance (ANOVA) was used to compare amongst the groups
of Doppler echocardiographic variables and other demographic variables.
As mentioned above, the standard error of estimate of the mean percent
signifies inter-observer variability. We used R 3.4.1 (Foundation for
Statistical Computing, Vienna, Austria) to run our analysis.