Statistical analysis
All continuous variables were expressed as means ± standard deviations
and compared using independent-sample Student t-tests or Mann-WhitneyU test. Categorical variables were expressed as frequencies and
percentages and compared using Pearson’s chi-square test or Fisher’s
exact tests. Univariate and multivariate logistic regression models with
backward elimination processes were performed to identify independent
risk factors associated with the occurrence of ERAT after surgical AF
ablation. The p - value for variables to enter and stay in the
prediction models was set at 0.05.
Time to first LR was computed and plotted using the Kaplan-Meier method
and compared using log-rank test. Cox proportional hazards regression
analyses were used to estimate hazard ratio (HRs) with 95% confidence
intervals (CIs). Variables reported in Tables 1 and 2 with a p -
value of ≤ 0.05 in the univariate analyses were candidates for the
multivariable Cox proportional hazards models. The final models were
determined using backward elimination processes. To redefine an ideal
cut-off value for the blanking periods, a receiver operating
characteristic (ROC) analysis was performed, the area under the curve
(AUC) was calculated, and the possible cut-off points were selected. All
statistical analyses were performed using R software version 3.5.3
(https://cran.r-project.org/).