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Does Atrial Fibrillation Burden Measured by Continuous Monitoring During the Blanking Period Predict the Response to Ablation at 12-Month Follow-Up?
Study Questions:
What is the efficacy of continuous atrial fibrillation (AF) monitoring with an implanted monitor to assess the AF burden measured continuously during the first months postablation, and its relationship to subsequent AF recurrences?
Methods:
A total of 613 patients with symptomatic drug-refractory AF (17% with persistent AF) were part of this retrospective analysis. All patients underwent circumferential pulmonary vein isolation and were implanted with a subcutaneous AF monitor (Reveal XT, Medtronic) for collecting data on AF burden (AF%) during a 12-month follow-up period. AF freedom (responders) was defined as AF% ≤0.5% during each monthly telemetric follow-up. A receiver operating characteristic curve analysis was performed to identify the value in AF% during the first months in the postablation blanking period that was predictive of later recurrence of AF. Sensitivity of 90% was selected as the target value.
Results:
After the first ablation procedure, 396 of the 613 patients (65%) were responders (AF ≤0.5%) at 12 months: 346 of 508 (68%) in the paroxysmal AF group and 50 of 105 (47%) in the persistent AF group. Using the receiver operating characteristic curve, the specificity corresponding to 90% sensitivity was 85% for AF% at 2 months. The corresponding threshold in the AF burden during the blanking period able to identify patients at risk for late recurrences was 4.5%, corresponding to a cumulative 65.9 hours (2.75 days) spent in AF during the first 2 months. In a multivariate analysis, AF% <4.5% during the first 2 months was highly significant (p < 0.001), and the odds ratio of responders/nonresponders was 39.8 (95% confidence interval, 19.1-82.9).
Conclusions:
The authors concluded that the AF burden measured during the blanking period can predict the response to catheter ablation at 12 months.
Perspective:
The study reports that AF% continuously measured by an implanted device during the first 2 months postablation was a powerful predictor of late AF recurrences. Importantly, a threshold of 4.5% in the AF% during these 2 months may be a valuable cutoff for identifying patients at risk for late recurrences. Given the retrospective nature of this analysis, prospective validation is indicated.
Keywords: Recurrence, Follow-Up Studies, Furylfuramide, Pulmonary Veins, Atrial Fibrillation, Heart Rate, Catheter Ablation
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