Statistical Analysis
Continuous variables were described with measures of central tendency and dispersion (mean and standard deviation). Categorical variables were described as frequencies or mode when appropriate. Continuous variables were evaluated by t -test, and categorical variables compared withχ 2 or Fisher’s exact test. The cumulative probability of survival free from atrial arrhythmia was displayed according to the Kaplan–Meier method, with comparisons of cumulative event rates by the log-rank test. Follow-up for all patients was censored at one year after repeat ablation. A p-value of < 0.05 was considered statistically significant. All analyses were performed using SPSS Statistics Software for Windows version 23.0 (IBM Corporation, Armonk, New York).