Limitations
We encountered several limitations in this study. First, this is a retrospective, single-center study. Therefore, it was not randomized. EIVOM was performed in all cases with the amenable VOM as often as possible. Second, the ablation strategy was changed during the research period. During a certain period, linear ablation for the left atrial bottom line was performed less than for the roof line. Therefore, a significant difference was observed between the two groups regarding the bottom line ablation. Third, a total of 23 patients were not followed because of personal reasons. It might have had an effect on the result of the AF/AT- free survival rate. Fourth, the right PV and bottom line reconnections were significantly higher in the EIVOM/RF group than in the RF group. It was possible that these differences had a distinct impact on the AF/AT- free survival rate. Fifth, as was previously mentioned, we determined the first re-ablation site according to the information on the electrogram sequences recorded inside the CS. If we achieved an MI line block through EIVOM or RF ablations in the CS, we would determine that reconnection existed only in the epicardium. However, both EIVOM and RF ablations were possible in the development of a transmural lesion. Sixth, it was impossible to evaluate the pure effect of EIVOM in the subsequent ablation session, because the MI area was already ablated by RF in the first session. Finally, the reconnection rates shown in Table 3 occurred only in AF recurrence or AT cases, which went into a subsequent ablation session. The true reconnection rate was limited due to MI durability when the success cases were unidentified.