Incidence and Predictors of Very Late Recurrence of Atrial Fibrillation Following Cryoballoon Pulmonary Vein Isolation.

Background: A very late recurrence (VLR) of atrial fibrillation (AF) is considered present when the first recurrence of AF occurs ≥12 months following ablation. Prior studies characterizing VLR have not used an implantable loop recorder for ECG monitoring. Thus, it is unknown whether VLR truly occurs or whether these patients have simply had unrecognized AF. Our objective was to assess the incidence and predictors of VLR in patients who underwent cryoballoon pulmonary vein isolation alone, had an implantable loop recorder, and were confirmed AF free for at least 1 year.

Methods: We enrolled consecutive patients with paroxysmal or persistent AF who underwent cryoballoon pulmonary vein isolation and had an implantable loop recorder implanted <3 months post-ablation. Patients free of AF 1 year post-ablation were followed prospectively for recurrent AF. All AF episodes were adjudicated.

Results: We included 188 patients (66±10 years; 116 [62%] men; 102 [54%] paroxysmal AF; CHADS-VASc, 2.6±1.7). After 1 year post-pulmonary vein isolation, 93 (49%) patients remained AF free. During subsequent follow-up, 30 (32%) patients had VLR of AF. The only independent risk factor for VLR was an elevated CHADS-VASc score (hazard ratio, 1.317 [95% CI, 1.033-1.6979]; =0.026). Patients with CHADS-VASc score ≥4 represented a quarter of the population and were at the highest risk.

Conclusions: Our data using implantable loop recorders for continuous ECG monitoring post-AF ablation show that VLR occurs in a third of patients after an apparently successful cryoballoon pulmonary vein isolation procedure. Additional strategies are needed to ensure long-term freedom from AF recurrences in these high-risk patients.