title: Performance of an external transtelephonic loop recorder for automated detection of paroxysmal atrial fibrillation.
abstract: BACKGROUND
  Although atrial fibrillation (AF) is the most commonly encountered arrhythmia, some of the properties make its detection challenging. In daily practice, underdiagnosis can lead to less effective treatment in prevention of stroke. Based on data from studies on treatment of AF, more intensive follow-up strategies, including 7-day Holter recording, 30-day event recording, and even implantable cardiac monitoring devices, are suggested. The study purpose is to evaluate the performance of a continuous single-channel loop recorder with automatic AF detection and transtelephonic electrocardiogram (ECG) transmission capabilities.
  
  
  RESULTS
  A consecutive cohort of 153 patients admitted to the stroke unit with a presumptive diagnosis of ischemic cerebrovascular accident was screened for AF. Twenty-four-hour rhythm observation was performed using a single-channel external loop recorder (ELR) configured for automated AF detection. A total of 45 patients with a known history of AF, AF on the admission ECG, or incomplete registrations were excluded. Extensive additional frequency-based settings were used to establish a reference registration. In total, 2923 recordings were transmitted. We evaluated all events, of which 1190 were designated by the device as AF. The sensitivity, specificity, PPV, and NPV for identifying AF using the ELR were, respectively, 93%, 51%, 5%, and 99%.
  
  
  CONCLUSIONS
  In this ELR validation study, the dedicated AF detection algorithm showed to be highly sensitive but not specific for AF. Applicability of an ELR might be limited for efficacious detection of AF, as manual verification is mandatory for a vast amount of recordings.
authors.affiliation: Thoraxcenter, Medisch Spectrum Twente, Enschede, The Netherlands.
authors.forename: Bob Oude
authors.initials: BO
authors.lastname: Velthuis
authors.forename: Jorieke
authors.initials: J
authors.lastname: Bos
authors.forename: Karin
authors.initials: K
authors.lastname: Kraaier
authors.forename: Jeroen
authors.initials: J
authors.lastname: Stevenhagen
authors.forename: Jurren M
authors.initials: JM
authors.lastname: van Opstal
authors.forename: Job
authors.initials: J
authors.lastname: van der Palen
authors.forename: Marcoen F
authors.initials: MF
authors.lastname: Scholten
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation* / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013686:Telemetry / Q000379:methods*
keywords: atrial fibrillation; monitoring; stroke; validation