A man in his early 40s with chest pain: STD in V1-V4, but posterior lead are negative

This study by Shah et al. shows that the STD of subendocardial ischemia (in contrast to posterior OMI) is maximal in V5 and V6.Shah A, Wagner GS, Green CL, et al. Electrocardiographic differentiation of the ST-segment depression of acute myocardial injury due to the left circumflex artery occlusion from that of myocardial ischemia of nonocclusive etiologies. Am J Cardiol [Internet] 1997;80(4):512 –3. Available from: https://europepmc.org/article/med/9285669However, STD in V1-V4 can occasionally be due to subendocardial ischemia.  If posterior leads also show ST depression, then subendocardial ischemia is probable!!  This review supports that, if it is subendocardial ischemia, it should manifest as STD in posterior leads in addition to anterior leads.  The subendocardial ischemia is diffuse, with ST depression pointing outward from all walls except for the " base " of the heart, which has no wall, and therefore the combined ST depression vector is towards the apex (V5, V6)(Wong et al.)Wong C-K. Usefulness of leads V7, V8, and V9 ST elevation to diagnose isolated posterior myocardial infarction. Int J Cardiol [Internet] 2011;146(3):467 –9. Available from: http://dx.doi.org/10.1016/j.ijcard.2010.10.137Matetzky-1:Matetzky S, Friemark D, Feinberg MS. Acute myocardial infarction with isolated ST-segment elevation in posterior chest leads V7-V9: “hidden” ST-segment elevations revealing acute posterior infarction. J Am Coll Cardiol 1999;34(3):748 –5...
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