Rapid accurate diagnosis of acute myocardial infarction in patients with non-traumatic chest pain within 1 h of admission.
BACKGROUND
Accurate diagnosis of impending acute myocardial infarction (AMI) in patients presenting at an emergency department with acute chest pain is essential for proper triage and treatment. We have developed an algorithm for the early diagnosis of AMI.


METHODS
The diagnostic performances of ECG, creatine kinase (CK) and creatine kinase isoenzyme MB (CKMB) activities, CKMB mass, myoglobin, and cardiac troponin T (cTnT) were compared for early diagnosis of AMI in 60 non-traumatic chest pain patients (22 AMI, 29 unstable angina, nine other diseases) on presentation to an internal medicine emergency department and 1 h thereafter. The classification and regression trees method was used for data analysis and revealed the following results.


RESULTS
In patients with electrocardographic signs of acute transmural myocardial ischaemia on admission (mostly regional ST-segment elevations), biochemical markers could not improve the diagnostic accuracy either on admission or 1 h later. By contrast, in patients with non-diagnostic ECG, CKMB mass concentration measured 1h after admission was the best discriminator between AMI and non-AMI patients (discriminator value 5.8 micrograms/l) and was superior to ECG and all other biochemical markers tested. This algorithm for diagnosing AMI is characterized by 96% sensitivity, 90% specificity, 84% positive predictive value, 97% negative predictive value, 92% accuracy, 0.05 negative likelihood ratio, and 9.1 positive likelihood ratio.


CONCLUSIONS
The classification procedure obtained allows accurate rapid and early diagnosis of AMI and could therefore be a valuable diagnostic aid to physicians of emergency medicine.
Mair
J
J
Department of Internal Medicine, University of Innsbruck School of Medicine, Austria.
Smidt
J
J
Lechleitner
P
P
Dienstl
F
F
Puschendorf
B
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000097:blood / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000706:statistics & numerical data; D004630:Emergencies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013997:Time Factors
D015415:Biomarkers