title: P-wave evidence as a method for improving algorithm to detect atrial fibrillation in insertable cardiac monitors.
abstract: BACKGROUND
  Frequent premature atrial contractions and sick sinus syndrome are primary causes of inappropriate atrial fibrillation (AF) detection in insertable cardiac monitors (ICMs).
  
  
  OBJECTIVE
  The study aimed to validate an algorithm designed to reduce inappropriate AF detection on the basis of the identification of a single P wave during the cardiac cycle.
  
  
  METHODS
  The original detection algorithm looks for evidence of AF based on differences in the pattern of R-R intervals over a 2-minute period. The improved algorithm reduces evidence for AF detection if P waves are detected. The algorithm was validated by using Holter data, which collected 2 leads of surface electrocardiogram and continuously uplinked ICM electrocardiogram over a 46-hour period. ICM detections were compared with Holter annotations to compute episode and duration detection performance.
  
  
  RESULTS
  Valid Holter recordings (8442 hours) were analyzed from 206 patients. True AF was observed in 76 patients, yielding 482 true AF episodes ≥2 minutes in duration and 1191 hours of AF. The algorithm correctly identified 97.8% of the total AF duration and 99.3% of the total sinus or non-AF rhythm duration. The algorithm detected 85% (90% per-patient average) of all AF episodes ≥2 minutes in duration, and 55% (78% per-patient average) of the detected episodes had AF. AF was found in 95% of the detected episodes >1 hour. The improved algorithm reduced inappropriate episodes and duration by 46% and 55%, respectively, while also reducing appropriate episodes and duration by 2% and 0.1%, respectively.
  
  
  CONCLUSIONS
  An improvement in the ICM algorithm for AF detection incorporating P-wave information substantially reduced inappropriately detected episodes and duration, with minimal reduction in sensitivity for detecting AF.
authors.affiliation: Department of Cardiology, Krankenhaus der Elisabethinen, Linz, Austria. Electronic address: helmut.puererfellner@elisabethinen.or.at.
authors.forename: Helmut
authors.initials: H
authors.lastname: Pürerfellner
authors.affiliation: State Research Institute of Circulation Pathology, Novosibirsk, Russia.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Pokushalov
authors.affiliation: Medtronic Incorporated, Mounds View, Minnesota.
authors.forename: Shantanu
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: Medtronic Incorporated, Mounds View, Minnesota.
authors.forename: Jodi
authors.initials: J
authors.lastname: Koehler
authors.affiliation: Medtronic Incorporated, Mounds View, Minnesota.
authors.forename: Ren
authors.initials: R
authors.lastname: Zhou
authors.affiliation: The National Institute of Cardiovascular Diseases, Bratislava, Slovakia.
authors.forename: Lubos
authors.initials: L
authors.lastname: Urban
authors.affiliation: Heart Center, University of Leipzig, Leipzig, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hindricks
mesh_terms: D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D003199:Computer Systems; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation*; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: Atrial fibrillation; Diagnosis; Insertable cardiac monitors; Monitoring