title: Atrial fibrillation induced by applying acetylcholine to subadventitial layer of pulmonary vein in normal canine heart.
abstract: OBJECTIVE
  We determined whether acetylcholine (Ach) application to the pulmonary vein (PV) wall could induce AF and clarified its mechanisms, and determined whether circumferential PV radiofrequency ablation (CPVA) could prevent Ach-induced AF in canine hearts.
  
  
  METHODS
  Thirty seven beagle dogs were used for the study. Ach was injected into the subadventitial layer of the left superior PV (LSPV), at different distance from the LSPV-left atrium junction (LSPV-LA-J) to locate AF initiation. When AF was not induced by Ach alone, programmed electrical stimulation (S1-S2 method) was added to elicit AF. Atropine was injected at the same site of Ach injection to determine whether muscarine-receptor blockade suppressed AF, and CPVA at the LSPV-LA-J was performed using a newly devised basket electrode-catheter.
  
  
  RESULTS
  AF was reproducibly induced by Ach injection in 19 of the 26 dogs (73%). S1-S2 method after Ach initiated AF in 5 of the remaining 7 dogs. Ach into the subadventitial layer of the LSPV, especially the distal portion, could elicit AF, which was preceded by pause (sinus arrest) ≥ 2.0 sec (37%) (pause-AF group), sinus bradycardia (32%) (brady-AF group) and sinus tachycardia (32%) (tachy-AF group). The time from Ach injection to AF initiation and AF duration were not significantly different between pause-AF, brady-AF and tachy-AF groups. AF was not initiated by injecting Ach after atropine pretreatment. To eliminate AF, 1-6 (average 4.1 ﾂｱ 1.2) CPVAs at the LSPV-LA-J were required.
  
  
  CONCLUSIONS
  Our observations suggest that local Ach application can initiate AF in PVs, preceded by a variety of modes such as pause, bradycardia or tachycardia, and an increase in vagal tone at the LSPV plays a critical role in eliciting AF in structurally normal heart.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Adachi
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Tanabe
authors.forename: Eri
authors.initials: E
authors.lastname: Toda
authors.forename: Makiyoshi
authors.initials: M
authors.lastname: Shima
authors.forename: Seiji
authors.initials: S
authors.lastname: Tamiya
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Fujii
authors.forename: Shigetaka
authors.initials: S
authors.lastname: Kanda
authors.forename: Mari
authors.initials: M
authors.lastname: Amino
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yoshikawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikari
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001281:Atrial Fibrillation / Q000139:chemically induced* / Q000517:prevention & control; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D017115:Catheter Ablation; D004285:Dogs; D004558:Electric Stimulation; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D011667:Pulmonary Veins / Q000033:anatomy & histology* / Q000187:drug effects*
chemical_list: D000109:Acetylcholine