Is this ST depression due to OMI or due to subendocardial ischemia? This is critical to distinguish, and this is a trick case!

We just today published this very important article in the Journal of the American Heart Association:Ischemic ST ‐Segment Depression Maximal in V1–V4 (Versus V5–V6) of Any Amplitude Is Specific for Occlusion Myocardial Infarction (Versus Nonocclusive Ischemia)full text: https://www.ahajournals.org/doi/pdf/10.1161/JAHA.121.022866However, if the patient has atrial fibrillation with RVR, one must first cardiovert and then re-assess.  STD Max V1-V4 can be due to subendocardial ischemia (not OMI) when there is tachycardia, especially if due to atrial fibrillation with RVR.I have long noticed this (but have not formally studied it), and just by chance I had this patient very recently who presented with chest pain and this ECG and no history of atrial fibrillation:Notice the STD diffusely, and in precordial leads it ismaximal in lead V3.  In sinus rhythm with a heart rate under 100, and in a chest pain patient, this is VERY specific for posterior OMI. One is tempted to diagnose posterior OMI, but one should resist that temptation!In the context of atrial fibrillation with rapid ventricular response, the correct management is to first cardiovert, then re-assess.This is what we did.  After giving 10 mg of etomidate (low dose propofol is fine as well), we did synchronized cardioversion with 200 J.He converted to sinus rhythm and we recorded this 12-lead ECG immediately after:Sinus rhythm with no ischemiaLearning point:ST Depression maximal in le...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs