Operator learning curve with a novel dual-energy lattice-tip ablation system

Background: The SPHERE Per-AF trial demonstrated noninferiority for a primary composite effectiveness endpoint in patients with persistent atrial fibrillation (AF) treated with a 9-mm, lattice-tip, pulsed field (PF)/radiofrequency (RF) system (74%) vs conventional contact force-sensing RF (65%). Although operators were highly experienced with the control, the vast majority was new to the investigational system. Objective: The aim of this study was to assess the learning curve using this novel system. Methods: Patients were grouped based on the sequential procedures performed per operator. Operators who performed ≤2 investigational procedures were excluded. The composite effectiveness endpoint was freedom from acute procedural failure, repeat ablation at any time, recurrence of arrhythmia, drug initiation/escalation, or cardioversion each at 1 year excluding a 3-month blanking period. Efficiency endpoints included “skin-to-skin” procedure time. Results: The total cohort included 443 patients (235 investigational [31 roll-in], 208 control). Primary effectiveness in the investigational cohort improved significantly with increased procedural order. Efficacy was 65% (74 of 114) for the first 5 patients per operator, 75% (33 of 44) for patients 6 to 10, and 80% (60 of 75) for patients >10. Kaplan-Meier effectiveness estimates at 1-year follow-up were significantly higher in the investigational cohort after 10 procedures performed, compared with control (80% vs 65%, P <.05). With the investigational system, total procedure time was reduced by 25 minutes (100 vs 125) within the first 5 procedures performed (P <.001). Conclusion: AF ablation with a novel dual-energy, lattice-tip ablation system resulted in greater clinical efficacy compared with conventional RF after a rapid operator learning curve, with superior procedural efficiency noted from the initial procedures onward.