title: Performance of an implantable automatic atrial fibrillation detection device: impact of software adjustments and relevance of manual episode analysis.
abstract: OBJECTIVE
  Implantable loop recorders (ILRs) with specific atrial fibrillation (AF) detection algorithms (ILR-AF) have been developed for continuous AF monitoring. We sought to analyse the clinical value of a new AF monitoring device and to compare it to serial 7-day Holter.
  
  
  RESULTS
  Sixty-four consecutive patients suffering from paroxysmal AF were included in this prospective analysis and received an ILR-AF. Manual electrogram analysis was performed for each automatically detected episode and each was categorized into one of three possible diagnoses: 'no AF', 'definite AF', and 'possible AF' (non-diagnostic). Analysis was performed separately before and after a software upgrade that was introduced during the course of the study. A subgroup of patients (51 of 64) underwent AF catheter ablation with subsequent serial 7-day Holter in comparison with the ILR-AF. A total of 333 interrogations were performed (203 before and 130 after software upgrade). The number of patients with AF misdetection was significantly reduced from 72 to 44% following the software upgrade (P = 0.001). The number of patients with non-diagnostic interrogations went from 38 to 16% (P = 0.001). Compared with serial 7-day Holter, the ILR-AF had a tendency to detect a higher number of patients with AF recurrences (31 vs. 24%; P = 0.125).
  
  
  CONCLUSIONS
  The rate of AF detection on ILR-AF may be higher compared with standard AF monitoring. However, false-positive AF recordings hamper the clinical value. Developments in device technology and device handling are necessary to minimize non-diagnostic interrogations.
authors.affiliation: Heart Center, Department of Electrophysiology, University of Leipzig, Strümpellstrasse 39, 04289 Leipzig, Germany.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Eitel
authors.forename: Daniela
authors.initials: D
authors.lastname: Husser
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hindricks
authors.forename: Manuela
authors.initials: M
authors.lastname: Frühauf
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hilbert
authors.forename: Arash
authors.initials: A
authors.lastname: Arya
authors.forename: Thomas
authors.initials: T
authors.lastname: Gaspar
authors.forename: Ulrike
authors.initials: U
authors.lastname: Wetzel
authors.forename: Andreas
authors.initials: A
authors.lastname: Bollmann
authors.forename: Christopher
authors.initials: C
authors.lastname: Piorkowski
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D012984:Software; D013997:Time Factors