Impact of the timing of early recurrences during the blanking period in patients after cryoballoon ablation: insights from the COMPARE CRYO study using continuous rhythm monitoring

Abstract

Abstract Background Early recurrences (ER) during the blanking period after pulmonary vein isolation (PVI) are common. While many of those correlate to late recurrences (LR) after the blanking period, some do not. The impact of the timing of ER is difficult to assess with non-invasive Holter monitoring due to under sampling. Purpose To evaluate the impact of the timing of ER after cryoballoon ablation using continuous rhythm monitoring by means of an implantable cardiac monitor (ICM). Methods This is a prespecified sub study of the COMPARE-CRYO study. The trial enrolled patients with paroxysmal atrial fibrillation and compared PVI with the PolarX cryoballoon and the ArcticFront cryoballoon. All patients underwent ICM implantation at the end of the PVI. ER was defined as recurrence of any atrial arrhythmia > 30 seconds between days 0-90 after PVI. LR was defined as recurrence of any atrial arrhythmia > 30 seconds between days 91-365. Results ER occurred in 116 of 201 patients (58%). A total of 5330 episodes occurred, 4210 in patients with LR and 1120 in patients without LR (Figure 1A). Median time to the latest episode of ER in the blanking period was 18 days (IQR 8.5-36.5) in patients with no LR and 80 days (IQR 27-89) in patients with LR (p<0.001). The latest episode of ER occurred between days 0-30, 31-60 and 61-90 in 41%, 13% and 46% of patients respectively. Freedom from recurrence of atrial arrhythmias 1 year after the PVI was 81% in patients without ER and 37% in patients with ER (p<0.001, Figure 1B). When patients were classified according to their latest episode of ER occurring between days 0-30, 31-60 and 61-90, freedom from any atrial arrhythmia at 1 year was 60%, 53% and 11% (p<0.001, Figure 1C) respectively. ROC analyses revealed a strong correlation of LR with the timing of the latest episode of ER in the blanking period (AUC=0.81, p<0.001) with an optimal cutoff value at 61 days (SN 64%, SP 88%). Median AF burden in the blanking period was 0% (IQR 0-0) in patients with ER but no LR and 0.2% (IQR 0-2) in patients with ER and LR (p<0.001). This was similarly true for all individual months (0-30 days: 0% vs. 1.8%, p<0.001, 31-60 days: 0% vs. 0.1%, p<0.001, 61-90 days: 0% vs. 0.1%, p p<0.001). There were no differences in the duration of ER episodes or in clinical characteristics between patients with and without LR Conclusion ER after cryoballoon PVI is common. While ER during the first and second month after PVI disappear in the majority of patients, presence of ER in the third month after PVI are highly predictive for ablation failure.