Study limitations
This was a retrospective study with a limited sample size that was
performed at a single center. The choice of ablation strategy was
dependent on operator discretion, and we did not apply ablation to all
DFAs based on the mapping results. In particular, an analysis focused on
elimination of DFAs and their outcomes should be performed
prospectively. However, the issue persists regarding selection of the
appropriate method for eliminating DFAs. Indeed, although point-by-point
ablation was often performed, our data showed that most DFAs in LAA were
not targeted due to the possible risk of electrical isolation of LAA.
There may be some debate regarding whether aggressive ablation should be
adopted for this sensitive region. DFAs were not observed in nine of the
35 patients. Indeed, DFAs were absent in these cases; however, we may
have overlooked DFAs for the following reasons: 1) it is difficult to
evaluate electrograms in some locations such as in the LA anteroseptal
region or inner portion of the luminal structure due to inadequate
deployment of the mapping catheter; 2) number of acquisition points in
this study may be insufficient to assess the entire LA; and 3) the DFAs
may be located outside the LA, since previous studies demonstrated the
presence of AF drivers in regions outside the LA such as the right
atrium or epicardium.3,10,18,19 Furthermore, DFAs were
determined based on the map created prior to catheter ablation; thus,
there is the possibility that the distribution of DCL could change and
de novo DFAs may emerge after ablation. In some cases, it is preferable
to perform further mapping outside of the LA and repetitive mapping. The
composite endpoint of our study consisted of the acute success of the
procedure, requiring further evaluation of the long-term outcomes after
ablation. Further prospective, large-scale, multicenter studies with
sufficient accumulated samples are necessary to evaluate the efficiency
of the specific ablation strategy targeting DFAs.