**4.4 Brain natriuretic peptide**

Zyng et al. reported that high brain natriuretic peptide (BNP) levels were associated with AF recurrence after catheter ablation [28]. In contrast, we studied postprocedural ablation predictors of AF recurrence after univariate and multivariate analyses in 82 patients, which found no relationship between BNP level and AF recurrence. This might be attributed to the policy of the institute, in which AF ablation is performed after adequate medical treatment for heart failure is administered. Thus, the relationship between BNP level and AF recurrence after catheter ablation requires further investigation.
