Comparison of acute lesion extent after pulsed field ablation and cryoballoon ablation - Insight from the randomized SINGLE-SHOT CHAMPION trial

The SINGLE SHOT CHAMPION multicenter trial compares the effectiveness of pulsed-field ablation (PFA) versus cryoballoon ablation (CBA) for pulmonary vein isolation (PVI) in patients with symptomatic paroxysmal atrial fibrillation (AF). In a pre-specified substudy, post-ablation 3D electroanatomic mapping (3D-EAM) was used.

To verify the endpoint of PVI and to compare the acute lesion extent after fluoroscopy-guided single-shot PVI with PFA and CBA using adjunctive 3D-EAM at the end of the procedures.

Patients with symptomatic paroxysmal AF were enrolled and randomized 1:1 to fluoroscopy-guided PVI using PFA or CBA. Following PVI, the first 25 patients in each group underwent high-density left atrial 3D-EAM. Data was collected on the PV isolation status and the mini mal width of the posterior wall channel, defined as the shortest distance between low-voltage borders observed on bipolar amplitude voltage maps with thresholds set to 0.05 mV and 0.5 mV (Figure 1).

50 Post-ablation maps were available for analysis. LA size was not different between the groups. In the PFA group, a median number of 40 (IQR 34-44) PFA applications was performed and in the CBA group, a median number of 6 (IQR 5-7) CBA applications was performed. On post-ablation 3D-EAM, residual PV conduction was found in 4 pulmonary veins in 4 cases after CBA (16%, two right inferior, one left inferior, one left superior pulmonary vein). No residual PV conduction was found after PFA (p=.11). Median minimal posterior wall channel width was 19.6 mm (IQR 12.7-25.0 mm). PFA led to wider PVI with lesions extending further into the posterior wall, resulting in narrower median width of the minimal posterior wall channel compared to CBA (14.0 mm, IQR 10.5-20.6 mm vs. 24.0 mm, IQR 19.1-26.9 mm, p<.001). Additionally, unintended posterior wall interruption by connecting lesions occurred in 3 (12%) PFA cases and no CBA cases (p=.23). Patients with inadvertent posterior wall interruptions showed lower left atrial volume compared to patients without (median LAVI 18.5 ml/m2, IQR 14.8-19.2 ml/m2, vs. 35.6 ml/m2, IQR 29.3-41.0 ml/m2, p=.006).

In this randomized comparison, residual PV conduction was found in 16% after CBA and in 0% after PFA when using high-density 3D-EAM after ablation. The level of isolation was wider with PFA compared to CBA, and inadvertent posterior wall interruption occurred in some of the PFA patients, in particular in the presence of small atria.