Pulmonary Vein Stenosis After Catheter Ablation Electroporation Versus Radiofrequency

Background-Radiofrequency ablation inside pulmonary vein (PV) ostia can cause PV stenosis. A novel alternative method of ablation is irreversible electroporation, but the long-term response of PVs to electroporation ablation is unknown. Methods and Results-In ten 6-month-old pigs (60-75 kg), the response of PVs to circular electroporation and radiofrequency ablation was compared. Ten consecutive, nonarcing, electroporation applications of 200 J were delivered 5 to 10 mm inside 1 of the 2 main PVs, using a custom-deflectable, 18-mm circular decapolar catheter. Inside the other PV, circular radiofrequency ablation was performed using 30 W radiofrequency applications via an irrigated 4-mm ablation catheter. PV angiograms were made before ablation, immediately after ablation, and after 3-month survival. PV diameters and heart size were measured. With electroporation ablation, PV ostial diameter decreased 11 +/- 10% directly after ablation, but had increased 19 +/- 11% after 3 months. With radiofrequency ablation, PV ostial diameter decreased 23 +/- 15% directly after ablation and remained 7 +/- 17% smaller after 3 months compared with preablation diameter despite a 21 +/- 7% increase in heart size during aging from 6 to 9 months. Conclusions-In this porcine model, multiple circumferential 200-J electroporation applications inside the PV ostia do not affect PV diameter at 3-month follow-up. Radiofrequency ablation inside PV ostia causes considerable PV stenosis directly after ablation, which persists after 3 months.