A tale of two formulas: Differentiation of subtle anterior MI from benign ST segment elevation.

BACKGROUND

It may sometimes be difficult to differentiate subtle ST-segment elevation (STE) due to anterior myocardial infarction (MI) from benign variant (BV) STE. Recently, two related formulas were proposed for this purpose. However, they have never been tested in an external population.

MATERIALS AND METHODS

Consecutive patients from May 2017 to January 2018, who were admitted with the diagnosis of acute anterior STEMI, were enrolled. Electrocardiograms were systematically reviewed and only subtle ones were included. First 200 consecutive patients with noncardiac chest pain were also enrolled as a control group. Relevant electrocardiographic parameters were measured.

RESULTS

A total of 379 anterior MI and 200 BV-STE cases were enrolled during study period. A total of 241 patients in STEMI group were excluded for not matching subtleness criteria, four patients in control group were also excluded because of prior left-anterior descending artery intervention. The three-variable formula, with recommended cut-point of 23.5, had a sensitivity, specificity, and diagnostic accuracy of 73.9%, 86.7%, and 81.4%, respectively. The four-variable formula, with the published cut-point of 18.2, had a sensitivity, specificity, and diagnostic accuracy of 83.3%, 87.7%, and 85.9%, respectively.

CONCLUSION

Three- and four-variable formulas with recommended cutoffs have a reasonable sensitivity, specificity, and diagnostic accuracy in differentiating subtle STEMI with BV-STE. Although both perform well, the four-variable formula has a higher sensitivity, specificity, and diagnostic accuracy and should be preferred.