title: Clinical features of emergency electrocardiography in patients with acute myocardial infarction caused by left main trunk obstruction.
abstract: BACKGROUND
  To diagnose left main trunk (LMT) infarction by 12-lead standard electrocardiogram (ECG) is an important emergency technique, but the features in LMT infarctions have not been clarified.
  
  
  RESULTS
  The study enrolled 140 subjects who were divided into 4 groups according to the location of the culprit artery: 35 with LMT, 35 with left anterior descending artery (LAD), 35 with right coronary artery and 35 with left circumflex artery. Various parameters obtained from the ECGs were analyzed. Average QTc interval (0.51 +/- 0.06 s) in LMT group was markedly longer than that in the 3 other groups. Average QRS axis (-10 +/- 77 degrees) in LMT infarction showed a remarkable left deviation. ST-segment elevation in lead aVR occurred in 28 patients (80.0%) in the LMT group. The ECG features of the LMT group could be classified into 2 main groups: right bundle branch block (RBBB) with a marked left axis deviation (RBBB + LADEV type) and ST-segment elevation in leads V2-5, I and aVL without abnormal axis deviation (LAD type).
  
  
  CONCLUSIONS
  Either ST-segment elevation in lead aVR and marked prolongation of both the QRS width and QTc interval with a prominent abnormal axis deviation or ST-segment elevation in the broad anterior precordial lead with a normal QRS axis strongly suggests LMT infarction.
authors.affiliation: Department of Regenerative and Cardiovascular Medicine, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hirano
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishigaki
authors.forename: Kenji
authors.initials: K
authors.lastname: Sou
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kubota
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Ojio
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Shinya
authors.initials: S
authors.lastname: Minatoguchi
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Katsumi
authors.initials: K
authors.lastname: Ueno
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hosokawa
authors.forename: Norihiko
authors.initials: N
authors.lastname: Morita
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Nagano
authors.forename: Takahiko
authors.initials: T
authors.lastname: Suzuki
authors.forename: Sachirou
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000175:diagnosis; D001158:Arteries / Q000473:pathology; D002037:Bundle-Branch Block; D004562:Electrocardiography; D004632:Emergency Medical Services; D005260:Female; D006801:Humans; D008133:Long QT Syndrome; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*