Background: Many previous studies explore inflammation factors have been associated with atrial fibrillation (AF). And it also has been demonstrated that B-type natriuretic peptide (BNP) was elevated in patients with AF. We hypothesized that these biochemical markers can predict the recurrence and clinical outcome after radiofrequency catheter ablation (RFCA) of AF. Methods and Results: In 81 patients with AF (paroxysmal AF (PAF) 45; persistent AF (PeAF) 36; male: female = 66:15; mean age 54.2 짹 10.9 years old), we measured the plasma levels of BNP, C-reactive protein (CRP), and troponin I (TpI) immediately before and 24 hours after RFCA. Results: 1. CRP (2.9 짹 5.2 mg/L to 20.1 짹 15.9 mg/L, p<0.0001) and TpI (0.02 짹 0.01 ng/mL to 1.88 짹 0.96 ng/mL; p<0.0001) significantly increased after RFCA, whereas BNP decreased (71.8 짹 80.0 pg/mL to 52.4 짹 46.6 pg/mL, p<0.05). 2. Patients with PeAF who underwent RFCA with higher number of RF energy (162.1 짹 62.8 times vs. 115.6 짹 39.6 times, p<0.0001) had significantly lower BNP (��BNP:-47.6 짹 80.3 pg/mL vs. 3.12 짹 80.7 pg/mL, p<0.01) and higher TpI (��TpI: 2.2 짹 1.1 ng/mL vs. 1.6 짹 0.7 ng/mL, p<0.05) than those with PAF. 3. During 3.3 짹 1.3 months of follow-up, AF recurred in 8 out of 81 patients (PAF 3/45 (6.7%) vs. PeAF 5/36 (13.9%); p=NS). The magnitude of the changes in CRP, TpI, and BNP after RFCA had no predictive value of AF recurrence. Conclusion: RFCA for AF significantly increased CRP and TpI, and decreased BNP. However, these biochemical markers are not reliable parameters to predict recurrence of AF after RFCA.