title: Pulmonary vein region ablation in experimental vagal atrial fibrillation: role of pulmonary veins versus autonomic ganglia.
abstract: BACKGROUND
  Pulmonary vein (PV) -encircling radiofrequency ablation frequently is effective in vagal atrial fibrillation (AF), and there is evidence that PVs may be particularly prone to cholinergically induced arrhythmia mechanisms. However, PV ablation procedures also can affect intracardiac autonomic ganglia. The present study examined the relative role of PVs versus peri-PV autonomic ganglia in an experimental vagal AF model.
  
  
  RESULTS
  Cholinergic AF was studied under carbachol infusion in coronary perfused canine left atrial PV preparations in vitro and with cervical vagal stimulation in vivo. Carbachol caused dose-dependent AF promotion in vitro, which was not affected by excision of all PVs. Sustained AF could be induced easily in all dogs during vagal nerve stimulation in vivo both before and after isolation of all PVs with encircling lesions created by a bipolar radiofrequency ablation clamp device. PV elimination had no effect on atrial effective refractory period or its responses to cholinergic stimulation. Autonomic ganglia were identified by bradycardic and/or tachycardic responses to high-frequency subthreshold local stimulation. Ablation of the autonomic ganglia overlying all PV ostia suppressed the effective refractory period-abbreviating and AF-promoting effects of cervical vagal stimulation, whereas ablation of only left- or right-sided PV ostial ganglia failed to suppress AF. Dominant-frequency analysis suggested that the success of ablation in suppressing vagal AF depended on the elimination of high-frequency driver regions.
  
  
  CONCLUSIONS
  Intact PVs are not needed for maintenance of experimental cholinergic AF. Ablation of the autonomic ganglia at the base of the PVs suppresses vagal responses and may contribute to the effectiveness of PV-directed ablation procedures in vagal AF.
authors.affiliation: Department of Medicine, Montreal Heart Institute, Montreal, Quebec, Canada.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lemola
authors.forename: Denis
authors.initials: D
authors.lastname: Chartier
authors.forename: Yung-Hsin
authors.initials: YH
authors.lastname: Yeh
authors.forename: Marc
authors.initials: M
authors.lastname: Dubuc
authors.forename: Raymond
authors.initials: R
authors.lastname: Cartier
authors.forename: Andrew
authors.initials: A
authors.lastname: Armour
authors.forename: Michael
authors.initials: M
authors.lastname: Ting
authors.forename: Masao
authors.initials: M
authors.lastname: Sakabe
authors.forename: Akiko
authors.initials: A
authors.lastname: Shiroshita-Takeshita
authors.forename: Philippe
authors.initials: P
authors.lastname: Comtois
authors.forename: Stanley
authors.initials: S
authors.lastname: Nattel
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000628:therapy*; D002217:Carbachol; D017115:Catheter Ablation / Q000379:methods*; D018679:Cholinergic Agonists; D004195:Disease Models, Animal; D004285:Dogs; D005725:Ganglia, Autonomic / Q000601:surgery*; D011667:Pulmonary Veins / Q000503:physiopathology*; D014630:Vagus Nerve / Q000503:physiopathology*
chemical_list: D018679:Cholinergic Agonists; D002217:Carbachol