title: DC cardioversion of persistent atrial fibrillation: a comparison of two protocols.
abstract: BACKGROUND
  Current guidelines for transthoracic direct-current cardioversion (DCCV) of atrial fibrillation (AF) recommend a step-up energy protocol. The aim of this study was to compare such a protocol with a protocol involving a high initial energy shock, anteroposterior paddle position and reversal of shock polarity, on cardioversion efficacy, total energy delivery, use of sedation and patient tolerability.
  
  
  METHODS
  261 patients (mean age 71+/-10 years, 62% male) referred for elective DCCV of persistent AF were enrolled. Patients were randomised to either protocol A: (1) 200 J anteroapical, (2) 360 J anteroapical, (3) 360 J anteroposterior; or protocol B: (1) 360 J anteroapical, (2) 360 J anteroposterior, and (3) 360 J posteroanterior. All procedures were performed under sedation with intravenous diazepam.
  
  
  RESULTS
  Protocol B improved shock success rates (protocol A first shock success rate=42%, protocol B=68%, p<0.001; protocol A second shock success rate=72%, protocol B 86%, p=0.006; protocol A third shock success rate=83%, protocol B=92%, p=0.03) and required fewer shocks to achieve sinus rhythm (1.3+/-0.6) compared with protocol A (1.6+/-0.7, p<0.001). There were no differences in cumulative energy used (protocol A 473+/-286 J, protocol B 436+/-273 J, p=0.24) or sedation requirements (protocol A diazepam 22.1+/-9.0 mg, protocol B 21.7+/-8.9 mg, p=0.75). Both protocols were equally well tolerated by patients.
  
  
  CONCLUSIONS
  High initial energy increased success rates and decreased the number of shocks but resulted in similar cumulative energy delivery, sedation use and patient tolerability compared with a conventional step-up protocol.
authors.affiliation: Department of Cardiology, Eastbourne General Hospital, Eastbourne, UK. LBoodhoo@aol.com
authors.forename: Lana
authors.initials: L
authors.lastname: Boodhoo
authors.forename: Andrew R J
authors.initials: AR
authors.lastname: Mitchell
authors.forename: George
authors.initials: G
authors.lastname: Bordoli
authors.forename: Guy
authors.initials: G
authors.lastname: Lloyd
authors.forename: Nikhil
authors.initials: N
authors.lastname: Patel
authors.forename: Neil
authors.initials: N
authors.lastname: Sulke
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy*; D002985:Clinical Protocols; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male