Impact of pre-existent areas of complex fractionated atrial electrograms on outcome after pulmonary vein isolation

Background: Atrial fibrillation (AF) drivers outside pulmonary veins (PV) may account for failure after PV isolation. The aim of this study was to characterize pre-existent areas of complex fractionated atrial electrograms (CFAEs) recorded in right atrium (RA) and in coronary sinus (CS) during catheter-based PV isolation and to assess their relation to outcome. Methods and results: With a tricuspid annulus and CS mapping, CFAEs were retrospectively identified in consecutive patients who underwent PV isolation. Of 224 patients, 161 were found to have CFAEs (81%). No clinical variable was found to be predictive of CFAEs presence. By Kaplan-Meier analysis, following a median follow-up of 23.7 months after a single ablation procedure, 62.8% of patients in the CFAEs(+) group and 85.4% of those in the CFAEs(-) group were free from recurrent atrial tachyarrhythmias (p=0.013). Multivariable Cox regression analysis showed that CFAEs evidence was an independent predictor of recurrence (p=0.007). Conclusions: Pre-existent CFAEs, that can be easily identified in RA and CS during PV isolation, are a powerful independent predictor for AF recurrence. This finding may be helpful for refining AF ablation strategies.