title: Elevated platelet activating factor level in ischemia-related arrhythmia and its electrophysiological effect on myocardium.
abstract: OBJECTIVE
  The mechanism through which platelet activating factor (PAF) induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction (AMI) and the underlying mechanism.
  
  
  METHODS
  (1) Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram (ECG) was recorded continuously. (2) Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. (3) PAF perfusion and standard microelectrode recording were performed on guinea pig papillary muscles.
  
  
  RESULTS
  In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization (APD90)under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions.
  
  
  CONCLUSIONS
  AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.
authors.affiliation: Emergency Department, China-Japan Friendship Hospital, Ministry of Health, Beijing 100029, China. taoyongkang@163.com
authors.forename: Yong Kang
authors.initials: YK
authors.lastname: Tao
authors.forename: Shui Ping
authors.initials: SP
authors.lastname: Zhao
authors.forename: Pu Lin
authors.initials: PL
authors.lastname: Yu
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
authors.forename: Cheng Dong
authors.initials: CD
authors.lastname: Gu
authors.forename: Hong Tao
authors.initials: HT
authors.lastname: Sun
authors.forename: Guo Qiang
authors.initials: GQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D010972:Platelet Activating Factor / Q000378:metabolism*; D013552:Swine
chemical_list: D010972:Platelet Activating Factor
keywords: Acute myocardial infarction; Fatal arrhythmia; Ischemia; Platelet activating factor (PAF)