Aims: The aim of this study was to investigate the change in plasma brain natriuretic peptide (BNP) level after pulmonary vein isolation (PVI) in paroxysmal (PAF), persistent (Pers-AF), and permanent atrial fibrillation (AF) (Perm-AF) patients. Methods and results: In 96 lone AF patients (PAF = 65, Pers-AF = 17, and Perm-AF = 14), BNP was measured before and 3 months after successful PVIs. At baseline, in all patients, BNP was elevated and was significantly greater in Pers-AF and Perm-AF patients than PAF patients (P < 0.05). After 3 months of follow-up following multiple PVIs, AF recurred in 12 (18%) PAF, 7 (41%) Pers-AF, and 8 (57%) Perm-AF patients. In Pers-AF and Perm-AF patients, BNP at baseline did not predict AF recurrence. After the PVIs, BNP significantly decreased in PAF and Pers-AF patients (P = 0.005) but not in Perm-AF patients. An elevated BNP at baseline decreased to within-normal limits in all Pers-AF and Perm-AF patients without AF recurrences. In all seven (23%) patients, whose AF type improved after the PVIs, BNP decreased. Conclusion: The reduction in the BNP level after the PVI seemed to be a marker for a good outcome in AF post-ablation patients. © The European Society of Cardiology 2007. All rights reserved.