Safe and effective delivery of high-power, short-duration radiofrequency ablation lesions with a flexible-tip ablation catheter

BACKGROUND High-power, short-duration (HPSD) radiofrequency ablation (RFA) may reduce ablation time. Concerns that catheter -mounted thermocouples (TCs) can underestimate tissue tempera-ture, resulting in elevated risk of steam pop formation, potentially limit widespread adoption of HPSD ablation.OBJECTIVE The purpose of this study was to compare the safety and efficacy of HPSD and low-power, long-duration (LPLD) RFA in the context of pulmonary vein isolation (PVI).METHODS An open-irrigated ablation catheter with a contact force sensor and a flexible-tip electrode containing a TC at its distal end (TactiFlexTM Ablation Catheter, Sensor EnabledTM, Abbott) was used to isolate the left pulmonary veins (PVs) in 12 canines with HPSD RFA (50 W for 10 seconds) and LPLD RFA (30 W for a maximum of 60 seconds). PVI was assessed at 30 minutes and 28 6 3 days post -ablation. Computed tomographic scans were performed to assess PV stenosis after RFA. Lesions were evaluated with histopathology. RESULTS A total of 545 ablations were delivered: 252 with LPLD (0 steam pops) and 293 with HPSD RFA (2 steam pops) (P = .501).Ablation time required to achieve PVI was >3-fold shorter for HPSD than for LPLD RFA (P = .001). All 24 PVs were isolated 30 mi-nutes after ablation, with 12/12 LPLD-ablated and 11/12 HPSD-ablated PVs still isolated at follow-up. Histopathology revealed transmural ablations for HPSD and LPLD RFA. No major adverse events occurred. CONCLUSION An investigational ablation catheter effectively delivered RFA lesions. Ablation time required to achieve PVI with HPSD with this catheter was >3-fold shorter than with LPLD RFA.