Is creation of a fully circumferential lesion set necessary for laser balloon ablation-based pulmonary vein isolation?

Background: Despite reports of remote pulmonary vein (PV) stenosis after visually guided laser balloon (VGLB) ablation, circumferential (360°) lesion sets are routinely performed. This study aimed to determine whether fully circumferential lesion creations are required for all PVs to achieve PV isolations (PVIs) and to determine PV's vulnerability to chronic-phase stenosis.

Methods: Fifty-one patients with paroxysmal atrial fibrillation underwent mapping-guided PVIs using circular mapping catheters. VGLB ablation was performed circumferentially beginning at the 12 o'clock position and continued clockwise or counterclockwise. PVIs obtained within the bounds of the first half of the circumferential lesion (≤ 180°) were defined as "early PVIs."

Results: "Early PVIs" were documented in real time for 39% (80/204) of the PVs and at a significantly greater frequency among lower PVs than upper PVs (60.1% vs. 17.6%; p < 0.0001). The PV sleeve length, PV diameter, and isolation of ipsilateral PVs within a semicircular lesion set were identified as predictors of an "early PVI" phenomenon. The amount of energy delivered to the lower PVs was significantly less than that to the upper PVs (5553 [5089-6188] vs. 3559 [2793-4380] J; p < 0.0001), but the incidence of narrowing of the lower PVs at 6 months was comparable to that of the upper PVs (p = 0.73).

Conclusion: Our study revealed electrical isolations of more than 60% of the lower PVs while creating the first half of the circumferential lesions. Crosstalk via the carina region was presumably involved due to the preceding upper PVI. Further study is needed to determine whether energy delivery adjustments are needed for lower PVs to avoid chronic narrowing.