NPPB and atrial fibrillation: In the multivariate Cox proportional hazards regression analysis, ln BNP remained significantly associated with the recurrence of AF (adjusted HR = 1.286, 96% CI = 1.000–1.655, P = 0.049) when tested with the use of β-blocker and ln sTM, P values of which were < 0.10 in the univariate Cox regression analysis (Table 2).