Background: Pulmonary vein isolation is the cornerstone of most AF ablation procedures. Wide antral circumferential ablation (WACA) has been attributed more effective than ostial pulmonary vein isolation (PVI) in achieving freedom from atrial fibrillation (AF) recurrence. Pulsed field ablation (PFA) is a novel energy source with promising safety and efficacy advantages over existing ablation methods due to its unique myocardial tissue specificity, especially when applied on the posterior left atrial (LA) wall.

Objective: To evaluate feasibility and lesion formation during very wide antral circumferential PVI in comparison to ostial PVI using the PFA system.

Methods: Eighteen consecutive AF patients underwent first-time PFA under deep sedation. Patients eighter received ostial (ostial group: 89% paroxysmal AF; age: 61 years; 89% male) or wide antral (WACA group: 67% paroxysmal AF; age: 64 years; 56% male) PFA. Pre and post ablation LA voltage maps were acquired using a 20-pole spiral catheter together with a 3-dimensional electroanatomic mapping system (EnsiteX, Abbott, voltage cutoff ≤0.5 mV). On post ablation maps, lesion size by encircling the ablated area was measured. In all patients, 8 pulse trains (2kV/2.5 sec, bipolar, biphasic, 4x basket/flower configuration each) were delivered to each pulmonary vein (PV). In the WACA-group, extra pulse trains in flower configuration were added for to each PV in a wide antral position. Continuous intraluminal esophageal temperature (TESO) was monitored with an S-shaped esophageal temperature probe.

Results: A median of 8 (IQR 8;8) and 10 (IQR 9;12) pulse trains per PV for ostial and WACA PVI were applied. WACA PFA resulted in significant larger lesion formation (43.8 cm² [IQR 37.9; 50.6]) in comparison to ostial PFA (30.9 cm² [IQR 26.1; 33.7], p=0.002) with consecutive posterior LA wall isolation in 7/9 patients (Figure 1). No relevant TESO changes occurred (TESO_min 35.0 °C; TESO_max 37.0 °C).  

Conclusion: Wide antral circumferential PFA of the PVs is feasible and was associated with significant larger lesion formation in comparison to conventional ostial PFA. Concomitant posterior LA wall isolation occurred in the majority of patient and did not result in an increase on intraluminal esophageal temperatures.