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.