Pulsed field or cryoballoon ablation for paroxysmal atrial fibrillation—insights from acute and chronic electroanatomic remapping in the randomized SINGLE-SHOT CHAMPION trial

The SINGLE SHOT CHAMPION multicentre trial compared the effectiveness of pulsed-field ablation (PFA) and cryoballoon ablation (CBA) for pulmonary-vein isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). In a prespecified substudy, post-ablation three-dimensional electroanatomic mapping (3D-EAM) was performed, and repeat-procedure mapping data were analysed.

Patients were randomized 1:1 to fluoroscopy-guided PVI with PFA or CBA. The first 25 patients in each group underwent high-density 3D-EAM immediately after ablation. Acute PV isolation and lesion geometry were assessed using bipolar voltage thresholds of 0.1, 0.2, and 0.5 mV. Lesion durability was evaluated at clinically indicated repeat ablation. In acute post-ablation mapping, residual PV conduction was seen in 4/25 (16%) CBA patients and 0/25 PFA patients (P = 0.11). Inadvertent posterior wall conduction block occurred after PFA in 3 (12%) patients with small atria (mean LA volume 30.7 mL). PFA created larger left-sided lesions (antral area <0.5 mV: 5.7 mm² [IQR 4.6–6.5] vs. 4.4 mm² [IQR 2.5–5.5], P = 0.026) and narrower posterior wall channels (14.0 mm [IQR 10.5–20.6] vs. 24.0 mm [IQR 19.1–26.9], P < 0.001), indicating wide-antral isolation. At redo (n = 48), durable PVI was seen in 4/26 (15%) PFA and 3/22 (14%) CBA patients and in 63/102 (62%) veins after PFA and 52/82 (63%) after CBA (P = 0.88).

Fluoroscopy- and electrocardiogram-guided PVI can result in incomplete PV isolation after CBA or unintentional posterior wall block after PFA. In the acute mapping cohort, PFA yielded broader left-sided lesions than CBA; in a separate redo cohort, chronic PV durability was similar for both modalities.