Statistical analyses were performed using SPSS version 25 (IBM Corp., Armonk, NY, USA). Data are expressed as the mean±standard deviation (SD) or number (percentage). Differences in parameters between responders and non-responders were analyzed using Student’st-test for continuous variables and Fisher’s exact test for categorical variables. The Mann-Whitney U test was used for continuous variables that were highly skewed. Survival curves were constructed using the Kaplan–Meier method and compared using the log-rank test. The association between potential predictors of the recurrence of AF after bepridil discontinuation was assessed by a univariate Cox regression analysis. The following variables were selected for the univariate analysis: age, sex, body mass index, AF history, presence of hypertension, diabetes mellitus, CHADS₂ score, duration of bepridil use, LA volume index, LA reverse remodeling, and the recurrence of AF during the blanking period. Predictive factors with P values of <0.05 in a univariate analysis were entered into the multivariate Cox regression analysis. Two-sided P values of <0.05 were considered statistically significant.