Open window mapping with extended early meets late algorithm vs. conventional mapping for accessory pathway ablation

Catheter ablation of accessory pathway is the treatment of choice for patients with symptomatic Wolff-Parkinson-White (WPW) syndrome. Accessory pathway (AP) identification relies on point-by-point mapping, raising the need for more precise and efficient methods. High-density open window mapping (OWM) combined with the extended early meets late (EEML) algorithm, utilizing 3D electroanatomic mapping systems, is a promising alternative. However, its role in clinical practice lacks comprehensive investigation, necessitating a comparison with conventional mapping.

A prospective cohort study of patients referred for AP ablation evaluated the OWM strategy, comparing it with a retrospective cohort using conventional mapping. Procedure variables, including radiofrequency (RF), fluoroscopy, mapping and procedure times along with total mapping points were compared. Long-term recurrence rates were assessed.

42 patients in the OWM group and 34 in the conventional group were included. The OWM strategy exhibited a significantly lower total mapping time (p = 0.030) despite acquiring more points (p < 0.001) than the conventional group. OWM was associated with reduced fluoroscopy time (12.0 (9.0-16) vs. 19 (11-30) minutes, p = 0.009) and RF time (p = 0.021). Long-term recurrence rates were comparable between groups (7.1% OWM vs. 17.7% conventional mapping, p = 0.284). At a median follow-up of 16.2 (4.6-39.4) months there were not significant differences in recurrence-free survival (p = 0.509).

OWM with the EEML algorithm is a feasible tool for precise AP location and ablation, associated with less fluoroscopy time, RF time, and total mapping time. Long-term recurrence rates were similar to conventional mapping. Prospective studies are warranted for further validation.