Thursday, August 16, 2018

A Simplified Formula Discriminating Subtle Anterior Wall Myocardial Infarction from Normal Variant ST-Segment Elevation

Dr. Emre Aslanger has published a simpler formula for differentiating electrocardiographically subtle LAD occlusion from normal variant ST elevation.

Here is the paper:
Aslanger E et al.  A Simplified Formula Discriminating Subtle Anterior Wall Myocardial Infarction from Normal Variant ST-Segment Elevation. American Journal of Cardiology.  https://doi.org/10.1016/j.amjcard.2018.06.053
https://www.sciencedirect.com/science/article/pii/S0002914918314206

Here is the simplified 4-variable formula:
(R-wave amplitude in lead V4 + QRS amplitude in V2) – (QT interval in millimeters + STE60 in V3)

This eliminates the QT correction and eliminates the constants.

This new practical formula had an excellent area-under curve of 0.963 (95% confidence interval, 0.946 to 0.980, p<0 .001="" nbsp="" p="">
At a cutpoint of 12, it had a sensitivity, specificity and diagnostic accuracy of 86.9%, 92.3%, and 90.1%, respectively.

My more complicated 4-variable formula was this:
(1.062 x STE at 60 ms after the J-point in V3 in mm) + (0.052 x computerized QTc) - (0.151 x QRSV2) - (0.268 x R-wave Amplitude in V4 in mm).

My formula is based on this paper:  

A value greater than 18.2 is quite sensitive and specific for LAD occlusion. 

This 4-variable formula has an associated iPhone app: 

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