title: [Impact of magnetic field exposure on cardiac autonomic tone and inducibility of atrial fibrillation in dogs].
abstract: OBJECTIVE
  To observe the maximal heart rate changes, atrioventricular (A-V) conduction block and atrial fibrillation (AF) inducibility in dogs with vagosympathetic trunk exposed to electromagnetic fields (EMFs).
  
  
  METHODS
  The vagosympathetic trunk of adult dogs was separated and exposed to EMFs 0.043 kHz (2.87 microG, n = 5) and to EMFs 2 kHz (0.34 microG, n = 6) for two to three hours. Simultaneously, the vagosympathetic trunk was stimulated with 20 Hz frequency and 1 - 8 V intensity for 0.1 ms. Heart rate, presence of A-V conduction block and AF inducibility were determined.
  
  
  RESULTS
  After 5-minutes exposure to EMFs 0.043 kHz (2.87 microG), the maximal heart rate decreased 29%, the voltage applied to vagosympathetic trunk required to induce A-V conduction block decreased by 60% in experimental group versus 5% increase in control group. This effect lasted 2 to 3 hours. While vagosympathetic trunk exposure to EMFs 2 kHz (0.34 microG) was associated with significant increase in the incidence of atrial premature beats, atrial tachycardia and AF, these effects could be blocked by propranolol and atropine.
  
  
  CONCLUSIONS
  Our results showed that 0.043 kHz (2.87 microG) EMFs exposure might reduce while 2 kHz (0.34 microG) EMFs exposure might increase AF inducibility. Our study thus suggested autonomic nervous system of dogs could be affected by EMFs exposure and 0.043 kHz (2.87 microG) EMFs exposure might be a novel option for AF prevention.
authors.affiliation: Laboratory of Arrhythmia, First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Hong-Bin
authors.initials: HB
authors.lastname: Wang
authors.forename: Qi-Na
authors.initials: QN
authors.lastname: Zhou
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.forename: Ming
authors.initials: M
authors.lastname: Zuo
authors.forename: Mei
authors.initials: M
authors.lastname: Zhuo
authors.forename: Shang-Lei
authors.initials: SL
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: Yue-Mei
authors.initials: YM
authors.lastname: Hou
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology* / Q000503:physiopathology*; D004285:Dogs; D006339:Heart Rate; D008280:Magnetics; D014630:Vagus Nerve / Q000503:physiopathology*