Significance of left circumflex artery-related acute myocardial infarction without ST-T changes.
BACKGROUND
Left circumflex (LC)-related acute myocardial infarction (AMI) presenting without ST-T changes has been underdiagnosed in the emergency department. There is little information on its clinical features and significance.


OBJECTIVE
The aims of the study were to investigate the clinical characteristics and outcomes of LC-related AMI without ST-T changes.


METHODS
Ninety-six patients were admitted for LC-related AMI. Comparisons between those with and without ST-T changes were analyzed.


RESULTS
Twenty-two patients (23%) did not have ST-T changes, whereas 74 patients (77%) had them. Patients without ST-T changes had younger age (55.6 + or - 16.8 vs 62.6 + or - 12.0 years, P = .03), fewer presented as Killip III/IV (4.5% vs 27.4%, P = .02) and with lower creatine kinase (1647.3 + or - 1602.2 vs 2778.2 + or - 2343.3 IU/L, P = .037) and creatine kinase-MB (136.8 + or - 130.3 vs 247.7 + or - 200.0 IU/L, P = .017), and more were with concurrent culprit lesion in the middle or distal LC and right- or balanced-dominant coronary circulation (86.4% vs 44.6%, P < .001). During follow-up, the need for repeat percutaneous coronary intervention (48.6% vs 45.5%, P = .40) and recurrent infarction (13.5% vs 13.6%, P = .62) were similar between the 2 groups. The 30-day mortality (0% vs 5.4%, P = .35) and overall mortality rate (4.5% vs 12.2%, P = .28) between them were not different statistically.


CONCLUSIONS
The relatively lower prevalence of LC-related AMI without ST-T changes in the study might be underestimated. These patients have smaller infarct size than patients with ST-T changes without differences in the short- and long-term outcomes between them.
Chua
Su-Kiat
SK
Section of Cardiology, Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan.
Shyu
Kou-Gi
KG
Cheng
Jun-Jack
JJ
Liou
Jer-Young
JY
Lin
Sheng-Chang
SC
Hung
Huei-Fong
HF
Lee
Shih-Huang
SH
Chiu
Chiung-Zuan
CZ
Lo
Huey-Ming
HM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D003951:Diagnostic Errors / Q000517:prevention & control*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D016896:Treatment Outcome