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.