Dynamic ST Depression in precordial leads. Does this transient STD signify subendocardial ischemia?

This case was written up by one of our fantastic 3rd year residents, Michael Fischer.  Edits by Smith.A mid 60s male with past history of 2 prior STEMI(+) OMIs s/p stenting (most recently ~2 years ago) had onset of substernal chest pain after he came inside from smoking a cigarette. He reported becoming diaphoretic and also having pain in his L hand. After approximately one hour, he called 911.  Medics arrived and recorded a prehospital ECG:Sinus rhythm.  Deep QS-waves in inferior leads. Tall R-wave in V2, but no definite ST shifts or hyperacute T-waves.He was given aspirin and sublingual nitroglycerin.He arrived at the emergency department by ambulance with continued chest pain. His initial ED ECG was as follows:--The most glaring abnormality in this ECG is thenew ST depression in lead V2.  --However, there is also STD in V3.  --There is nearly 1 mm STD in both leads.  --There are also inferior QS-waves, consistent with his previous MIs with stenting of the RCA.There was a previous ECG from 2 years prior, recorded the day after his previous stent:This shows subacute inferior MI, and looks to be nearly complete (transmural completed infarct. (QS-waves and slight STE with shallow T-wave inversion.)Smith comment: seeing this made me curious as to whether it was indeed a very large infarct.  In fact, there had been 2 previous inferoposterior infarcts, and the patient presented rather late for the 2nd one, resulting...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs