title: Duty-cycled unipolar/bipolar versus conventional radiofrequency ablation in paroxysmal and persistent atrial fibrillation.
abstract: BACKGROUND
  Duty-cycled (DC) radiofrequency ablation (RFA) for atrial fibrillation (AF) has been introduced, however, data on large patient series and comparison to conventional RFA are scarce.
  
  
  METHODS
  Between 2006 and 2008 DC RFA was performed in 209 consecutive patients (143 (68%) paroxysmal and 66 (32%) persistent AF). As controls served 211 patients, 155 (73%) with paroxysmal and 56 (27%) with persistent AF (p=0.3). In DC RFA, the pulmonary veins (PV) were isolated followed by ablation at the septum and left atrium, if AF persisted. Conventional PV isolation was followed by anatomical lines at the roof and mitral isthmus.
  
  
  RESULTS
  Freedom of paroxysmal AF was demonstrated after 1.08 DC RFA procedures per patient in 82% and after 1.19 conventional procedures in 87% after 8.5 ± 6.5 months (ns). In persistent AF, success rates were 79% after 1.35 DC RFA procedures and 80% after 1.34 conventional procedures after 11.5 ± 8.5 months (ns). The subgroup analysis of 119 patients with follow-up ≥ 12 months (17.5 [14.1-23.6] months) showed similar results. Left atrial flutter occurred in 3% and 8% after paroxysmal AF ablation (p < 0.05) and in 12% and 23% after persistent AF ablation (p=0.1). Multivariate predictors for success in both groups were age, left atrial size, presence of persistent vs. paroxysmal AF and previous pacemaker implantation, but not the ablation technique used. Non-fatal complications were seen in 2.8% with no differences between the groups.
  
  
  CONCLUSIONS
  Outcome in DC RFA is similar to conventional RFA with a final success rate exceeding 80% in both paroxysmal and persistent AF in the absence of fatal complications.
authors.affiliation: Cardiovascular Center, Clinic im Park, Seestrasse 220, 8027 Zurich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Tivig
authors.forename: Lam
authors.initials: L
authors.lastname: Dang
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Brunner-La Rocca
authors.forename: Sibel
authors.initials: S
authors.lastname: Özcan
authors.forename: Firat
authors.initials: F
authors.lastname: Duru
authors.forename: Christoph
authors.initials: C
authors.lastname: Scharf
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D016022:Case-Control Studies; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome