The predicament of an electrophysiologist: Ablating the left common pulmonary vein

Two randomized, prospective, multicenter studies, the Fire and Ice trial and the CIRCA‐DOSE study confirmed no difference in 1‐year efficacy between point‐by‐point radiofrequency (RF) and cryoballoon (CB) ablation for pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, variations in pulmonary vein (PV) anatomy may negatively impact the acute and long‐term outcomes. A left common pulmonary vein (LCPV) is frequently encountered during catheter ablation of AF. An LCPV is defined by a common trunk measuring ≥5mm in length. The incidence of an LCPV varies by imaging modality. In patients undergoing cardiac computed tomography (CT) or magnetic resonance imaging (MRI), an LCPV is diagnosed in 8%–83%, while intraprocedural PV venography reveals an LCPV in 10%–30% of patients. An LCPV with a short common trunk is three times more common than a narrow, long (>15mm) common trunk. Conceptually, the larger geometry of the LCPV may limit the extent of ostial sealing using a fixed diameter 28‐mm CB. Nonetheless, two retrospective studies demonstrated equivalence in clinical outcomes in patients with and without LCPV undergoing CB ablation. Heeger et al. evaluated 670 patients undergoing second‐ generation 28‐mm CB PVI. The presence of an LCPV defined as a common trunk ≥5mm was established in 74 of 670 (11%) of patients using intraprocedural PV venography. Single‐shot antral isolation or sequential isolation of the superior and inferior LCPV branches was performed using a 240‐s freeze cycle with or without bonus freeze or alternatively a time‐to‐isolation protocol. All LCPVs were acutely isolated. During 1.9 ± 0.9 years of follow‐up rate of freedom from recurrent atrial arrhythmia was not significantly different compared to a matched cohort of 74 patients without LCPV (64% vs. 66%, p = .82). The approach to LCPV electrical isolation, antral, or sequential, had no impact on clinical outcomes. Stroeker et al. reported clinical outcomes in 433 patients undergoing second‐generation CB PVI. An LCPV was detected in 146 of 433 (34%) of patients during preprocedural CT imaging with a short common trunk defined as 5–10mm in length present in 75% of patients. Ablation targeted the LCPV ostium using a 180‐s freeze application. In the presence of a large‐diameter LCPV, superior and inferior segmental ablation was performed. All LCPVs were acutely isolated. After a 19 ±10‐month follow‐up, patients with an LCPV demonstrated similar outcomes compared with a propensity score‐matched cohort of 146 patients with conventional PV anatomy. Furthermore, no difference in outcome was seen between patients with the short or long common trunk, although single‐shot PVI was more commonly accomplished targeting an LCPV with a long common trunk due to its overall smaller vein diameter. By contrast, Shigeta et al. reported outcomes in 324 patients referred for second‐generation CB PVI, demonstrating a lower rate of freedom from recurrent atrial arrhythmia in patients with an LCPV during 15‐month follow‐up (74% vs. 88%, p = .02). Acute electrical isolation was not accomplished targeting 4 of 27 (15%) LCPVs, highlighting potential technical difficulties targeting this anatomical variant. A higher rate of arrhythmia recurrence amongst patients with an LCPV was also reported in a retrospective study by Beiert et al. Compared with the potential disadvantage of a fixed‐diameter CB, point‐by‐point RF ablation should allow flexible lesion delivery at the most antral aspect of the LCPV. However, retrospective studies comparing second‐generation CB to RF PVI in patients with an LCPV reported no significant difference in arrhythmia recurrence during follow‐up. In this issue of the Journal of Cardiovascular Electrophysiology, Larsen et al. report the results of a prespecified subanalysis based on data from the randomized, prospective, multicenter CIRCA‐DOSE trial comparing point‐by‐point contact force–guided RF ablation in combination with a three‐dimensional mapping system to second‐ generation 23‐ or 28‐mm CB PVI in patients with paroxysmal AF. An LCPV was observed during preprocedural cardiac CT or MRI or