TWOSOME trial: Randomized comparison of single-shot vs single-tip pulsed field ablation for pulmonary vein isolation

Pulsed field ablation (PFA) is an emerging technology to perform pulmonary vein isolation (PVI) in atrial fibrillation. Comparative data between different PFA systems are scarce.

This study aimed to provide the first head-to-head evaluation of 2 PFA technologies for index PVI.

Patients with paroxysmal atrial fibrillation were 1:1 randomized to single-shot (pentaspline catheter) or single-tip PFA (focal contact force-sensing ablation catheter). The primary endpoint was arrhythmia-free survival at 12 months; secondary endpoints included procedural characteristics, safety, and biomarker assessments.

100 patients were assigned to the single-shot or the single-tip PFA group. Baseline characteristics were comparable. Acute PVI was achieved in 100%. Single-shot PFA reduced total procedure time (44 ± 11 minutes vs 119 ± 30 minutes; P < .001) but required longer fluoroscopy time (14 ± 5 minutes vs 4 ± 2 minutes; P < .001). New-onset arrhythmias (6%) could only be treated in the single-tip PFA group. Major complications included 1 non-PFA-related stroke (single-shot group) and 1 pericardial tamponade during single-tip PFA. No permanent sequelae occurred. Troponin levels were higher with single-tip PFA. At 12 months, arrhythmia-free survival was 76% (single-shot group) and 82% (single-tip group), respectively (P = .46).

Both PFA systems achieved high acute PVI rates with favorable 1-year clinical outcomes. Single-shot PFA was associated with shorter procedure times and longer fluoroscopy times, whereas single-tip PFA allowed adjunctive ablation when required and was associated with higher postprocedural troponin T levels.