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.