Kosuge et al identified changes in the electrocardiogram associated with left main or triple vessel coronary artery disease in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). The authors are from Yokohama City University Medical Center.
Patient selection: non-ST-segment elevation ACS
Parameters:
(1) QRS duration in milliseconds
(2) ST segment elevation in lead aVR in mm
(3) serum troponin T
Parameter
Finding
OR
QRS duration
<= 90 milliseconds
1
> 90 milliseconds
33.4
ST segment elevation in lead aVR
< 0.5 mm
1
>= 0.5 mm
8.2
serum troponin T
normal
1
elevated
1.7
cumulative odds ratio =
= PRODUCT(OR for all 3 parameers)
Interpretation:
• If none of the risk factors are present then the risk of left mean or triple vessel coronary artery disease is low.
• If all 3 factors are present then the risk is high.
Performance:
• The prolongation in QRS duration has a sensitivity of 88% and specificity of 88%. It has a 97% negative predictive value. A QRS prongation > 100 ms was 99% specific.
• A large elevation in aVR may mean that the patient can no longer be classified as non-ST segment elevation.
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