Statistical analysis:
Patient characteristics were expressed as the mean ± standard deviation
or as percentages. Continuous variables in two groups were compared by
student t test or Man Whitney U test. Distribution of categorical
variables were analyzed by using χ2 or Fisher’s exact test when
appropriate. Pearson’s correlation was used to test the relationship
between the continuous variables. Significant parameters in the
univariate analysis (p= < 0.05) were included in the
multivariate analysis. Multivariate Cox regression analysis (enter
models) was used to determine independent predictors of AF. Receiver
operating characteristic (ROC) curves were plotted and area under the
curve (AUC) was calculated for the prediction of occurrence of atrial
fibrillation. All statistical analyses were performed with SPSS version
24.0 (SPSS, Inc, Chicago, IL), and P values of <0.05 were
considered as statistically significant.