Okada M, Tanaka N, Tanaka K, et al. - Among patients with atrial fibrillation (AF) and reduced left ventricular ejection fraction (LVEF), this inquiry was performed to assess the pre-procedural and post-procedural correlations between brain natriuretic peptide (BNP) concentrations and cardiac function as well as the links between the BNP concentrations and recurrence post-catheter ablation (CA). This study involved 217 patients with LVEF < 50% who underwent first-time CA of AF. At 3 months post-CA, a significant reduction in BNP levels and improvement in LVEF were evident. Following adjustment for cardiac measures significant in univariate analysis, it was shown in Cox proportional hazard regression analysis that significant predictors of AF recurrence were: early recurrence within the blanking period and increased post-procedural BNP levels but not pre-procedural BNP. Overall, experts identified post-procedural BNP concentrations at the end of the blanking period as a predictor of subsequent AF recurrence in patients exhibiting reduced LVEF, independent of early recurrence.