Introduction: The aim of this study was to identify if there is a threshold of AF burden during the first months post-ablation obtained through continuous subcutaneous monitoring that can identify patients at risk of subsequent AF recurrences.
Methods: 613 patients with symptomatic drug refractory AF (17% with persistent AF) were enrolled in this retrospective analysis. All patients underwent circumferential pulmunary vein isolation (PVI) and were implanted with an ILR for collecting data on AF burden during 12-month follow-up. AF freedom (Responders) was defined as AF%<0.5% during follow-up period. A ROC curve analysis was performed to identify the value of AF burden during the first 2 months post ablation (Blanking Period, BP) that was predictive of late recurrence of AF.
Results: After the first ablation procedure, 396 (65%) of the 613 patients were AF-free at 12-month: 346 out of 508 (68%) in the paroxysmal AF group and 50 out of 105 (47%) in the persistent AF group. Using the ROC curve (Fig 1), the specificity corresponding to 90% sensitivity was 75%. The corresponding threshold in the AF burden during the blanking period able to identify patients at risk of late recurrences was 7.1%, corresponding to 102h (= 4.25 days) in AF during the 2 months BP. At the multivariate analysis, a threshold in the AF burden <7.1% during BP was still highly significant (p<0.0001) and the odds of responders/non-responders was 21.5 (10.8 - 42.9).
Conclusions: The BP AF pattern predicted response to catheter ablation. An AF burden ?7.1% assessed by continuous monitoring was a powerful predictor of subsequent AF recurrence after initial ablation, and thus be an appropriate guide for early re-intervention.