title: R-wave detection by subcutaneous ECG. Possible use for analyzing R-R variability.
abstract: BACKGROUND
  Atrial arrhythmia (AA) discrimination remains a technological challenge for implanted cardiac devices. We examined the feasibility of R-wave detection by a subcutaneous far field ECG (SFFECG) and analysis of these signals for R to R variability as an indicator of atrial arrhythmia (AA).
  
  
  METHODS
  Surface ECG and SFFECG (from the pacemaker pocket) were recorded in sixteen patients (61.5 +/- 11.4 years) with AA. The SFFECG was recorded with a pacemaker sized four electrode array acutely placed in the pacemaker pocket during implantation. The signals were analyzed to obtain peak-to-peak R wave amplitude and R to R interval variability (indicative of AAs).
  
  
  RESULTS
  In sixteen patients R waves were visually discernible in all recordings. The percentage over and under detection for automatic R wave recognition SFFECG was 3 and 9%, respectively. R to R variability analysis using the SFFECG produced results concordant to those using the surface ECG.
  
  
  CONCLUSIONS
  SFFECG might be a helpful adjunct in implantable device systems for detection of R waves and may be used for measurement of R to R variability.
authors.affiliation: Medical Clinic I, Charité Hospital, Schumannstr. 20-21, 10089 Berlin, Germany. parwis.fotuhi@charite.de
authors.forename: P
authors.initials: P
authors.lastname: Fotuhi
authors.forename: W
authors.initials: W
authors.lastname: Combs
authors.forename: C
authors.initials: C
authors.lastname: Condie
authors.forename: H
authors.initials: H
authors.lastname: Theres
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.forename: K
authors.initials: K
authors.lastname: Stangl
authors.forename: G
authors.initials: G
authors.lastname: Baumann
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial