Pulmonary vein isolation (PVI) is the most effective means of maintaining sinus rhythm in atrial fibrillation (AF), while a widely used approach to PVI is point-by-point radiofrequency (RF) catheter ablation. High power short duration (HPSD) and very high power short duration e.g., 90W and 4 sec) are increasingly popular technologies, featuring higher power and shorter application durations compared to previous methods. vHPSD offers similar efficacy to HPSD, while further reducing procedure times. Atrioesophageal fistula (AEF) is a rare but deadly complication of PVI, while endoscopically detected esophageal lesions are surrogate markers for the risk of AEF. Furthermore, thermal complications include vagal lesions leading to gastroparesis. While there is considerable data on the thermal safety of HPSD technology, most studies of vHPSD focus on efficacy and a direct comparison in terms of esophageal safety is lacking. In this randomized, single-center study, we aim to compare the thermal safety of vHPSD to HPSD. Furthermore, we aimed to determine the anatomical and biophysical factors that predict thermal injury. Patients undergoing their first PVI for AF are randomized to either HPSD or vHPSD power setting. The primary endpoint of the study is the composite of esophageal mucosal lesion and gastroparesis, as assessed at the post-procedural endoscopy within 15 days after the PVI.

Inclusion Criteria:

- Patients with paroxysmal or persistent atrial fibrillation undergoing their first pulmonary vein isolation procedure

Exclusion Criteria:

• Additional ablation performed outside PVI
• Contraindications to postoperative upper endoscopy