Abstract 17752: Does a Three-month “Blanking Period” Also Exist After the Second Session of Atrial Fibrillation Ablation?

Abstract

Background: The concept of a blanking period within three months after the first session of radiofrequency (RF) catheter ablation for atrial fibrillation (AF) is widely accepted, but it remains unclear whether this phenomenon is also observed after the second session. We tried to examine the presence of a post second session blanking period, and the factors related to this phenomenon. Methods: Among 549 consecutive patients who underwent an initial AF ablation, 134 (96 males, 63 ± 10 years) received a second ablation procedure, and were followed for 634 ± 421 days thereafter. The patient clinical background, laboratory data, ablation procedures during the second session, and arrhythmia recurrences defined as any episodes of atrial tachyarrhythmias lasting ≥30 seconds were analyzed. Arrhythmia recurrences were classified into two categories: those seen within and after the first three months post ablation, which were defined as early period recurrences (EPRs), and late period recurrences (LPRs), respectively. Results: EPRs and LPRs developed in 28 (21%) and 25 (19%) patients, respectively. Although an EPR was an independent predictor of an LPR (hazard ratio, 8.17; 95% confidence interval 2.97-22.48), 13 of the 28 patients with EPRs (46%) did not experience LPRs, supporting the concept of a blanking period. Compared to the patients with both EPRs and LPRs, those who experienced only EPRs had a higher left ventricular ejection fraction (LVEF) (63.1 ± 2.3 vs. 71.3 ± 1.5%, P=0.006) and lower serum brain natriuretic peptide (BNP) level before the ablation session (169 ± 47 vs. 55 ± 12 pg/ml, P=0.015). There were no significant differences in the clinical background, left atrial diameter, amount of RF energy delivered, ablation procedures, and serum C-reactive protein (CRP) concentration after the session between these two groups. Conclusion: A three-month blanking period was also recognized after the second session of AF ablation. This phenomenon was related to the better patient cardiac function indicated by the LVEF and serum BNP, but was not associated with other clinical and laboratory parameters, including CRP, and ablation procedures.