Oesophageal safety of high and very high power short duration pulmonary vein isolation: a randomized comparison of the 50 W and 90 W power settings-the HPSD oesophagus study.

Aims: Point-by-point radiofrequency catheter ablation is commonly used for pulmonary vein isolation (PVI) in atrial fibrillation (AF). Very high power short duration (vHPSD) technology offers similar efficacy to high power short duration (HPSD) with reduced procedure times. A major complication of thermal ablation is atrio-oesophageal fistula (AEF), with oesophageal lesions and gastroparesis indicating increased risk. A direct comparison of HPSD and vHPSD regarding thermal safety is lacking. This randomized, single-centre study aimed to compare the thermal safety of vHPSD to HPSD and identify anatomical and biophysical predictors of thermal injury (ClinicalTrials.gov ID: NCT06617442). Methods and results: Patients undergoing first-time PVI for AF were randomized to either HPSD (50 W) or vHPSD (90 W). The study followed a non-inferiority design, with the primary endpoint being a composite of oesophageal mucosal lesion and gastroparesis, assessed via endoscopy within 15 days post-procedure. Pre-procedural computed tomography scans were analysed for anatomical risk factors. Among 100 patients (50 per group), the primary endpoint occurred in 7 (14%) of the vHPSD group and 6 (12%) of the HPSD group (estimated mean difference -2%, lower bound of one-sided 95% CI -0.13), confirming non-inferiority. A smaller inter-lesion distance on the posterior wall was associated with increased risk (3.76 mm vs. 4.16 mm, Conclusion: Pulmonary vein isolation using 90 W (vHPSD) applications was non-inferior to the 50 W (HPSD) power setting in terms of oesophageal safety. A smaller inter-lesion distance on the posterior wall was predictive of oesophageal injury.