Background Although radiofrequency catheter ablation(RFCA) of atrial fibrillation(AF) is an effective rhythm control strategy in selective patients, there is still a substantial number of recurrences. We explored the predictors for the recurrence of AF after RFCA. Methods and Results 77 patients(59males,54.9짹11.3years old) with AF (42paroxysmal AF(PAF),35persistent AF(PeAF))who underwent RFCA were included. We evaluated the clinical and electrophysiologic parameters and quantified the multiple serologic markers related to the matrix remodeling, fibrosis, and chemotaxis. Results: 1. During 13.7짹3.1months of follow-up, 79.2% of patients remained in sinus rhythm(SR) and 36.1% of them took anti-arrhythmic drugs. 20.8% developed recurrences 3months after RFCA. 2. The patients with recurrence had larger left atrium(LA)(46.5짹8.2mm vs. 40.9짹6.7mm, p<0.01), bigger anterior part volumes of LA measured by CT (65.7짹7.5% vs. 70.7짹5.0%, p<0.03), lower mean LA voltage quantified by NavX voltage mapping (4.85짹2.35mV vs. 7.70짹2.92mV, p<0.02), longer durations of RF energy application (94.6짹28.1min vs. 75.3짹27.6min, p<0.01), and higher post-RFCA levels of tissue inhibitor of metalloproteinase(TIMP)-1 (0.99짹0.24ng/mL vs. 0.77짹0.37ng/mL, p<0.03) than those without recurrence. 3. Pre-RFCA levels of pro-atrial natriuretic peptide(ANP) were significantly lower in patients with recurrence after PAF ablation (0.17짹0.37nmol/L vs. 1.55짹1.43nmol/L, p<0.03), but pro-ANP (2.70짹2.55nmol/L vs. 1.07짹1.31nmol/L, p<0.03)and matrix metalloproteinase(MMP)-2 (100.48짹2.71ng/mL vs. 81.91짹12.34ng/mL, p<0.04) were more pronounced in those with recurrence after PeAF ablation. 3. Among the patients with LA>42mm, pre-RFCA levels of E-selectin were significantly higher (28.6짹7.9ng/mL vs. 19.9짹9.9ng/mL, p<0.02) in patients with recurrence compared with those without recurrence. Conclusion The patients with bigger LA, especially with enlarged anterior LA, low LA voltages, and higher post-ablation TIMP-1 levels, were more likely to be susceptible to recurrences after RFCA of AF. The chronicity of AF and the LA size also influenced whether pro-ANP, MMP-2, or E-selectin could predict the recurrence of AF after RFCA.