title: Atrial defibrillation threshold as a novel predictor of clinical outcome of catheter ablation for persistent atrial fibrillation.
abstract: OBJECTIVE
  Catheter ablation for persistent atrial fibrillation (AF) is currently performed with different procedural endpoints. When AF did not terminate during ablation procedure, electrical cardioversion was performed at different defibrillation threshold (DFT) according to AF characteristics and atrial electrophysiologic substrates. We sought to evaluate the impact of atrial DFT after catheter ablation for persistent AF on clinical outcome.
  
  
  RESULTS
  We studied 128 patients with persistent AF (age 63±9 years, 106 men). After completion of circumferential pulmonary vein isolation, the left atrial substrate ablation was performed until AF terminated or all identified complex fractionated electrograms were eliminated. If AF did not terminate during ablation, an internal cardioversion protocol was started at 5J and was increased incrementally in 5 J steps until successful cardioversion was accomplished. Procedural AF termination was achieved in 50 patients (Group A). Atrial fibrillation was terminated by cardioversion with DFT≤10 J in 47 patients (Group B) and with DFT>10 J in 31 patients (Group C). At 14±7 follow-up months after 1.3±0.5 sessions, 47 (94%) Group A patients, 42 (89%) Group B patients, and 14 (45%) Group C patients remained in sinus rhythm. In multivariate analysis of Group B and Group C, DFT (hazard ratio 5.54, P<0.001) and AF duration (hazard ratio 3.74, P=0.011) were independent predictors of recurrent arrhythmia.
  
  
  CONCLUSIONS
  When AF does not terminate after the completion of predetermined stepwise ablation, further extensive ablation to terminate AF might be unnecessary if the AF can be successfully terminated by electrical cardioversion at low DFT.
authors.affiliation: Division of Cardiology, Cardiovascular Center, Tsuchiura Kyodo Hospital, 11-7 Manabe-Shinmachi, Tsuchiura, Ibaraki, Japan. yk.komat@gmail.com
authors.forename: Yuki
authors.initials: Y
authors.lastname: Komatsu
authors.forename: Kikuya
authors.initials: K
authors.lastname: Uno
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Otomo
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Nagata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ogura
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Egami
authors.forename: Kei
authors.initials: K
authors.lastname: Takayama
authors.forename: Ken
authors.initials: K
authors.lastname: Kakita
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Iesaka
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000517:prevention & control / Q000628:therapy*; D017115:Catheter Ablation / Q000379:methods*; D004554:Electric Countershock / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055502:Secondary Prevention; D016896:Treatment Outcome