The sites overlapping with LVAs
In the previous study, 77% of the high-DF sites overlapped with LVAs in
the LA13 using conventional mapping catheters, while
only 2.6% (22 sites out of 835) overlapped using the HDG in this study.
However, there was a significant difference in the number of high-DF
sites overlapping with LVAs between the patients with and without
recurrent AF/AT. The HDG might drastically exclude false LVAs, which
would help detect the AF substrate more accurately.
Furthermore, though the number of %NP≧50% sites overlapping with LVAs
in the LA was greater, there was no significant difference in that
number between the patients with and without recurrent AF/AT. The %NP
indicated the frequency of the presence of rotors within a relatively
large mapping area (diameter of 2.5 cm), and the area overlapping with
LVAs may not always reflect the exact overlapping sites between the
rotors and LVAs.
High-DF areas change spatiotemporally and the DF based ablation is still
controversial.12 However, drivers are harbored
within/in the vicinity of LVAs, and fractionated activity, rotational
activity, and discrete rapid local activity during AF in LVAs may
contribute to the formation of high-DFs.7,15 The
selection of high-DF sites overlapping with LVAs as targets may correct
the shortcoming of an ablation based on the DF.13 In
this study, a combination of frequency mapping and LVA mapping using the
HDG could detect the critical selective atrial substrate necessary to
maintain AF. Therefore, this strategy using the HDG could avoid any
excessive RF applications as compared to that using conventional
mapping.