['Oxidative stress is associated with atrial fibrillation (AF). However, little is known about the relationship between serum markers of oxidation and electrical activity in patients with AF.', 'The purpose of this study was to investigate the possible association between serum markers of reactive oxidative metabolism and atrial remodeling in paroxysmal and persistent AF.', 'Derivatives of reactive oxidative metabolites (DROM), an index of oxidative stress, were measured in 306 consecutive patients with AF (225 paroxysmal, 81 persistent) undergoing radiofrequency (RF) catheter ablation. Filtered P-wave duration by P-wave signal-averaged ECG and levels of high-sensitivity C-reactive protein (CRP) as an inflammatory marker also were measured.', 'Patients were followed up for 1.2 +/- 0.8 years. DROM levels in patients with persistent AF were significantly higher than in patients with paroxysmal AF (341.6 +/- 85.5 Carratelli [Carr] units vs 305.0 +/- 77.7 Carr units, P <.001). DROM levels showed a tighter, positive correlation with filtered P-wave duration in persistent AF patients (r = 0.56, P <.001) than in all AF patients (r = 0.13, P <.05). DROM levels also showed a weaker but significant correlation with high-sensitivity CRP in patients with AF. Kaplan-Meier analysis revealed that the highest quartile of basal DROM levels exhibited a significantly higher AF recurrence rate after RF catheter ablation in patients with paroxysmal AF (P <.01).'] Are reactive oxidative metabolites associated with atrial conduction disturbance in patients with atrial fibrillation?