Limitations
Several limitations of our study warrant mention. The main limitation is the study’s retrospective design, which meant that procedures were not standardized but rather at the discretion of the operator. Although prospective studies are necessary to solve these problems, standardization of procedures and long-term observation in an era of constantly improving strategies is not easy. Second, our follow up did not include routine continuous monitoring with implanted devices or transtelephonic electrocardiographic monitoring, and our AF-recurrence-free rate might therefore be underestimated. Third, since we performed voltage mapping using either bipolar 3.5-mm tip catheters or multi-electrode mapping catheters, the distribution of LVAs might have changed, given that multielectrode catheters produce smaller LVA measurements than ablation catheters. 34 Fourth, our conduct of voltage mapping after the completion of PV isolation and in the left atrium only might have influenced the prevalence of LVAs. Fifth, patients with the worst prognosis, namely those in whom a voltage map could not be obtained after the first PVI, were excluded. Sixth, the cut-off values (5 cm2 and 20 cm2) used for grouping were arbitrary. Finally, statistical analyses were limited by the relatively small size of the study population.