NPPB and chronic kidney disease: In the multivariate Cox proportional hazard model, adjusted for age, sex, duration after AF diagnosis, beta-blocker use before ablation, LAVI, BNP, Class III AAD use after ablation, as well as eGFR or CKD stage, an IS level ≥ 0.65 μg/mL remained as an independent predictor of AF recurrence (HR 3.60, 95% CI: 1.12–11.0, P = 0.032; and HR 3.67, 95% CI: 1.13–11.7, P = 0.031, respectively; Table 3).