title: Transvenous internal cardioversion for atrial fibrillation: a randomized comparison between catheters with different coil length.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of 2 different right atrial electrode coil lengths on energy and voltage requirements for transvenous atrial cardioversion.
  
  
  METHODS
  Twenty-six patients (mean age 61 +/- 11 years) with chronic persistent atrial fibrillation (AF) (mean duration 11 +/- 10 months) underwent transvenous cardioversion. A 6F catheter with a 5.5-cm coil was positioned in the coronary sinus. Another catheter with either a 5.5-cm or an 8-cm coil was positioned along the lateral wall of the right atrium, according to a randomized allocation. R wave-synchronized biphasic shocks were delivered according to a step-up protocol. After cardioversion of baseline AF, AF was reinduced, the right atrial catheter was substituted, and cardioversion was repeated with the alternative right atrial coil.
  
  
  RESULTS
  Successful cardioversion was obtained in all of the patients. Leading edge voltage of effective shocks was significantly lower when catheters with an 8-cm coil in right atrium were used compared with the alternative 5-cm coil catheters (301 +/- 80 volts vs 340 +/- 78 volts, P <.001), and delivered energy (6.75 +/- 4.25 joules vs 7.86 +/- 4.29 joules, P =.043) and shock impedance (60 +/- 9 ohm vs 66 +/- 10 ohm, P <.001) were lower. Moreover, shock-induced discomfort, evaluated by assessment of pain score, was reduced (3.69 +/- 1.09 vs 4.12 +/- 0.99, P =.035).
  
  
  CONCLUSIONS
  The use of a longer right atrial coil results in lower shock impedance, lower energy and voltage requirements, and lower discomfort during transvenous atrial cardioversion. The results of the current study are of value either for transvenous internal cardioversion of chronic persistent AF or for implantable atrial defibrillators.
authors.affiliation: Institute of Cardiology, University of Bologna, Azienda Ospedaliera S. Orsola-Malpighi, Bologna, Italy. cardio1@almadns.unibo.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffi
authors.forename: Claudia
authors.initials: C
authors.lastname: Camanini
authors.forename: Antonio
authors.initials: A
authors.lastname: Sammali
authors.forename: Letizia
authors.initials: L
authors.lastname: Bacchi
authors.forename: Peter
authors.initials: P
authors.lastname: Accorti
authors.forename: Richard
authors.initials: R
authors.lastname: Luceri
authors.forename: Romano
authors.initials: R
authors.lastname: Zannoli
authors.forename: Angelo
authors.initials: A
authors.lastname: Branzi
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D002908:Chronic Disease; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged