Impact of an LCPV in balloon based PVI procedures
There have been several prior reports on a CB guided PVI in patients of an LCPV. In the past, CB was considered technically challenging to achieve a PVI in patients with an LCPV, because the balloon size and lack of an appropriate balloon compliance made the complete occlusion of the PVs difficult. A previous study showed that atrial tachyarrhythmias were apt to recur after the ablation procedure using the first and second generation CBs5,11,12). A point by point RF energy application may be suitable for the isolation of an LCPV, because it can isolate the PV at the LCPV ostium regardless of the size, length, or configuration of the LCPV. However, prior studies comparing the 2nd generation CB and RF in patients with an LCPV reported no significant difference in the atrial tachyarrhythmia recurrence13,14). Moreover, a recent randomized clinical trial (CIRCA‐DOSE study) revealed the presence of an LCPV was associated with a trend towards higher rates of atrial tachyarrhythmia recurrence following the PVI15). In this study, no significant difference in the atrial tachyarrhythmia recurrence was observed in the patients with an LCPV randomized to those undergoing a CB ablation and those undergoing an RF ablation15).
On the other hand, Nakamura et al. investigated the efficacy and long-term outcome of a Hot-balloon guided PVI16). Of the patients in this study with an LCPV diameter of < 34 mm, 75% of the LCPVs were isolated at the ostium and 25% needed an individual isolation of the superior and inferior branches16). Nakamura et al. revealed that the presence of an LCPV was not associated with recurrent AF, and significantly fewer Hot-balloon applications were sufficient for accomplishing the PVI16).
An LCPV is generally defined as having a length of 5 mm or more from the PV ostium to the bifurcation point (a short common trunk is 5-15mm and a long common trunk more than 15mm6,7), but we defined the LCPV length between the PV ostium and bifurcation point as longer than 15mm on the MDCT findings. In the present study, a short LCPV was found in 21 patients. Since each short LCPV could not be isolated at the ostium, the superior and inferior branches of the LCPV had to be isolated individually. Therefore, those short LCPV cases were excluded from the present study analysis. There was no difference with regard to the total procedure time, ablation time for accomplishing the PVI, and atrial tachyarrhythmia recurrence between the patients with a short LCPV and those without an LCPV.
To the best of our knowledge, the present study was the first report to evaluate the efficacy of a VGLA guided PVI for an LCPV. The LB is so compliant that it can be inflated to any pressure and size change, which enables a maximum balloon/tissue contact regardless of the size or shape of each PV ostium. In the present study, we achieved a successful electrical isolation at the LCPV ostium in the majority of the patients with an LCPV. In addition, a comparable clinical result of atrial tachyarrhythmia recurrence could be observed in our study between the patients with and without an LCPV. Moreover, the ablation procedure time was shorter in the patients with an LCPV because the superior and inferior branches were isolated simultaneously with the VGLA as a result, which presumably attributed to a shorter catheter manipulation time. Although an electrical isolation at the LCPV ostium is difficult in cases with a large LCPV, VGLA could be selected as the first-line therapy in terms of the acute success and long-term clinical outcome.