title: Does atrial fibrillation burden measured by continuous monitoring during the blanking period predict the response to ablation at 12-month follow-up?
abstract: BACKGROUND
  Recurrences are common within the first months following atrial fibrillation (AF) ablation. However, prior studies using only intermittent ECG recording have not shown a powerful correlation with ultimate response.
  
  
  OBJECTIVE
  The purpose of this study was to use continuous AF monitoring with an implanted monitor to assess the AF burden measured continuously during the first months postablation and the relationship to subsequent AF recurrences.
  
  
  METHODS
  Six hundred thirteen 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 <.001), and the odds ratio of responders/nonresponders was 39.8 (95% CI, 19.1-82.9).
  
  
  CONCLUSIONS
  The AF burden measured during the blanking period can predict the response to catheter ablation at 12 months. AF% ≥4.5% at 2 months assessed by continuous monitoring is a powerful predictor of subsequent AF recurrences after initial ablation, thus providing relevant clinical information to select patients for early reintervention.
authors.affiliation: State Research Institute of Circulation Pathology, Novosibirsk, Russia. E.Pokushalov@gmail.com
authors.forename: Evgeny
authors.initials: E
authors.lastname: Pokushalov
authors.forename: Alexander
authors.initials: A
authors.lastname: Romanov
authors.forename: Giorgio
authors.initials: G
authors.lastname: Corbucci
authors.forename: Sevda
authors.initials: S
authors.lastname: Bairamova
authors.forename: Denis
authors.initials: D
authors.lastname: Losik
authors.forename: Alex
authors.initials: A
authors.lastname: Turov
authors.forename: Natalya
authors.initials: N
authors.lastname: Shirokova
authors.forename: Alexander
authors.initials: A
authors.lastname: Karaskov
authors.forename: Suneet
authors.initials: S
authors.lastname: Mittal
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Steinberg
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D017115:Catheter Ablation; D018450:Disease Progression; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000473:pathology / Q000601:surgery*; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome