title: Botulinum toxin injection in epicardial autonomic ganglia temporarily suppresses vagally mediated atrial fibrillation.
abstract: BACKGROUND
  Autonomic denervation may suppress atrial fibrillation (AF) vulnerability. This study was designed to assess the short- to mid-term effects of botulinum toxin, a cholinergic neurotransmission blocker, on AF inducibility.
  
  
  RESULTS
  A total of 23 mongrel dogs were studied. The sinus node and atrioventricular node epicardial fat pads were exposed through a right lateral thoracotomy. Botulinum toxin (Botox, 50 U per fat pad) or 0.9% normal saline (control) was injected into the center of each of the 2 fat pads. The electrophysiological effects were evaluated at 1, 2, and 3 weeks (7 to 8 animals at each time point) with and without cervical vagal stimulation. The vagal stimulation effects on the sinus and atrioventricular nodes were inhibited, and dispersion of atrial effective refractory period was lower at 1 week in the Botox group. Significant suppression of AF inducibility was observed at 1 week but disappeared at 2 and 3 weeks. These changes were not observed in the control group.
  
  
  CONCLUSIONS
  Temporary suppression of vagally mediated AF, for at least 1 week, was achieved with botulinum toxin injection in this canine model. This effect might be associated with reduced dispersion of effective refractory period. A temporary autonomic block using botulinum toxin might be a novel therapeutic option for several clinical conditions such as post-cardiac surgery AF.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. seil@snu.ac.kr
authors.forename: Seil
authors.initials: S
authors.lastname: Oh
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.forename: Youhua
authors.initials: Y
authors.lastname: Zhang
authors.forename: Todor N
authors.initials: TN
authors.lastname: Mazgalev
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000187:drug effects / Q000503:physiopathology; D001905:Botulinum Toxins / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018680:Cholinergic Antagonists / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D004285:Dogs; D004558:Electric Stimulation; D022062:Electrophysiologic Techniques, Cardiac; D005725:Ganglia, Autonomic / Q000187:drug effects* / Q000503:physiopathology; D007267:Injections; D008297:Male; D010496:Pericardium / Q000294:innervation*; D012032:Refractory Period, Electrophysiological / Q000187:drug effects / Q000502:physiology; D012849:Sinoatrial Node / Q000187:drug effects / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000187:drug effects* / Q000503:physiopathology
chemical_list: D018680:Cholinergic Antagonists; D001905:Botulinum Toxins