Clinical features of emergency electrocardiography in patients with acute myocardial infarction caused by left main trunk obstruction.
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.
Hirano
Tomohisa
T
Department of Regenerative and Cardiovascular Medicine, Gifu University Graduate School of Medicine, Gifu, Japan.
Tsuchiya
Kunihiko
K
Nishigaki
Kazuhiko
K
Sou
Kenji
K
Kubota
Tomoki
T
Ojio
Shinsuke
S
Kawasaki
Masanori
M
Minatoguchi
Shinya
S
Fujiwara
Hisayoshi
H
Ueno
Katsumi
K
Hosokawa
Hiroaki
H
Morita
Norihiko
N
Nagano
Toshihiko
T
Suzuki
Takahiko
T
Watanabe
Sachirou
S
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*