Baseline BNP Predicts Ablation Outcome in Male AF Patients. Background: Close association between atrial fibrillation (AF) and brain natriuretic peptide (BNP) has been demonstrated by several studies. Important gender differences exist in AF patients including a higher plasma BNP level in women. Therefore, it is imperative to evaluate the relationship between AF and BNP separately in men and women. Objective: This study examined possible gender-specific role of BNP in predicting procedure outcome in AF patients undergoing catheter ablation. Method: The study population included 568 consecutive patients (age 62 +/- 10, male 73%, paroxysmal 25%, persistent 38%, and long-standing persistent AF 37%) undergoing AF ablation, who had structurally normal heart and left ventricular ejection fraction >= 45%. Baseline BNP was measured in all. Patients were grouped into "normal" and "high" BNP based on gender-specific cut-off values (<50 and >= 50 pg/mL in males, <100 and >= 100 pg/mL in females). Result: Baseline BNP was significantly higher among women than men (126 +/- 112 versus 87 +/- 99, P = 0.009). At 12 +/- 6 month follow-up, 304 of 414 (73%) males and 98 of 154 (64%) females were AF/atrial tachycardia-free off antiarrhythmic drugs (log-rank P = 0.018). In multivariable analysis, BNP remained an independent predictor of AF recurrence (BNP = 50: hazard ratio [HR] 2.54, P = 0.006) in males. No such association was observed among females (BNP >= 100: HR 0.79, 95% CI 0.43-1.42; P = 0.426). Conclusion: Baseline BNP was found to be an independent predictor of AF recurrence in male patients undergoing ablation. This correlation between BNP and AF recurrence was not observed in females. Thus, BNP plays a gender-specific prognostic role in AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 858-865, August 2011)