Introduction: Pulsed-field ablation (PFA) and the multi‐electrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). Lesion extension and lesion formation of both systems are not yet assessed.

Purpose: We compared the acute lesion extent by measuring low-voltage areas before and after ablation in high-density maps and the release of biomolecules reflecting cardiac injury.

Methods: PVI was performed with a pentaspline catheter (FARAPULSE) or with the compliant multi‐electrode radiofrequency balloon (HELIOSTAR). Before and after PVI high-density mapping with CARTO3 (Biosense) was performed. In addition, blood samples were taken before transseptal puncture and after post-PVI remapping. Serum concentrations of high-sensitive Troponin I (hsTropI) were quantified by Immunoassay (Architect i2000SR).

Results: 50 patients undergoing PVI by PFA (n=26, age 71±10 y, 58% males, 58% persistent AF) or RFB (n=24, age 64±13 y, 54% males, 25% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses were n=34±5 and mean number RFB applications were n=8±3 per patient. Total posterior ablation area was larger after PFA (19.0±6.2 cm²) than after RFB (9.0±2.2 cm²; p<0.001). The posterior distance between septal and lateral lesions was shorter after PFA (23.7±10.5 mm) than after RFB (30.0±7.3 mm; p=0.021). In a total of 38 patients increase of hsTropI was higher after PFA (625±138 pg/ml, n=28) vs. RFB (148±36 pg/ml; n=10; p=0.049) indicating larger lesion extent by PFA.

Conclusion: PFA induces larger acute lesion areas and higher troponin release upon successful PVI than RFB-based PVI in this single-center series.