Impact of shortening the blanking period to 8 weeks after PVI: Insights from COMPARE-CRYO using continuous rhythm monitoring.

Background
Early recurrences of atrial tachyarrythmias (ERAT) after pulmonary vein isolation (PVI) are common. While many correlate to late recurrences (LR), some do not. The impact of ERAT timing is difficult to assess with non-invasive holter monitoring due to undersampling. The recommended duration of the blanking period (BP) was recently shortened from 90 days to 8 weeks.Objective
To evaluate the impact of ERAT timing after PVI and the effect of a shorter BP, using implantable cardiac monitors (ICM) for continuous rhythm monitoring.Methods
This is a prespecified substudy of the COMPARE-CRYO study, which enrolled patients with paroxysmal atrial fibrillation undergoing cryoballoon ablation. All patients underwent ICM implantation and the BP duration was 90 days.Results
A total of 5285 ERAT episodes occurred in 117/201 patients (58%). Freedom from LR was 82% vs. 37% in patients without vs. with ERAT (p<0.001). When patients were classified according to their last episode of ERAT occurring between days 0-30, 31-60 and 61-90, freedom from LR was 60%, 56% and 11% (p<0.001). Seven of the 201 patients (3.4%) had AF recurrence in the third month after ablation, but not between days 91-365, which reclassifies them from ablation success to ablation failure with the shortened 8-week BP.Conclusion
ERAT after PVI is common. The presence of ERAT in the third month after PVI was highly predictive for ablation failure, supporting the shortening of the BP duration to 8 weeks, however, the shorter BP reclassifies 3.4% of the patients to ablation failure instead of ablation success.