title: Randomised comparison of electrode positions for cardioversion of atrial fibrillation.
abstract: OBJECTIVE
  To compare the relative efficacy of anteroanterior v anteroposterior electrode pad positions for external cardioversion of atrial fibrillation.
  
  
  METHODS
  Prospective randomised trial.
  
  
  METHODS
  Tertiary referral cardiology centre in the United Kingdom.
  
  
  METHODS
  90 patients undergoing elective cardioversion for atrial fibrillation.
  
  
  METHODS
  Cardioversion was attempted with self adhesive electrode pads with an area of 106 cm2 placed either in the anteroanterior (AA) or anteroposterior (AP) positions. Initial shock was 100 J which, if unsuccessful, was followed by 200 J, 300 J, and 360 J if required. Peak current and transthoracic impedance were measured.
  
  
  METHODS
  Cardioversion success rate and energy requirements.
  
  
  RESULTS
  Cardioversion was successful in 81% of the patients (73/90). There was no statistically significant difference in the cardioversion success rate (AA 84%, 38/45 patients; AP 78%, 35/45 patients; p = 0.42) or mean (SD) energy requirement for all patients (AA 223 (96.1) J; AP 232 (110) J) or for patients who were successfully cardioverted (AA 197.9 (82.4) J; AP 195.4 (97.2) J; p = 0.9) between the two pad positions. The mean transthoracic impedance (TTI) for the first shock (AA 77.5 (18.4) ohms; AP 73.7 (18.7) ohms; p = 0.34) was not significantly different between the two groups. TTI correlated significantly with body mass index, percentage body fat, and chest AP diameter. There was a progressive decrease in TTI with serial shocks. While aetiology and TTI were the two independent significant predictive factors for energy requirement, duration of atrial fibrillation was the only independent predictor of cardioversion success in a multivariate analysis.
  
  
  CONCLUSIONS
  Electrode pad position is not a determinant of cardioversion success rate or energy requirement.
authors.affiliation: Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast BT12 6BA, Northern Ireland, UK. rmcc@pipex.dial.com
authors.forename: T P
authors.initials: TP
authors.lastname: Mathew
authors.forename: A
authors.initials: A
authors.lastname: Moore
authors.forename: M
authors.initials: M
authors.lastname: McIntyre
authors.forename: M T
authors.initials: MT
authors.lastname: Harbinson
authors.forename: N P
authors.initials: NP
authors.lastname: Campbell
authors.forename: A A
authors.initials: AA
authors.lastname: Adgey
authors.forename: G W
authors.initials: GW
authors.lastname: Dalzell
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology / Q000628:therapy*; D002307:Cardiography, Impedance; D004554:Electric Countershock / Q000379:methods*; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome