ST Depression Maximal in V1-V4 and Angio shows 3 Vessel Disease. Is it posterior? Which is the culprit?

A 70-something woman had acute chest pain.The ECG was texted to me with the words: " Acute chest pain. Could this be posterior MI? What do you make of the ST depression in V4-V6? "What do you think?My response: " The ST depression is maximal in V1-V4.  This is most consistent with a posterior MI.  If it sounds clinically like acute MI then this is good for activating the cath lab. "Her response: " Yeah, I did activate.  But the cardiology fellow told me he was sure it would not be a posterior MI because of diffuse ST depression.  He suggested that we should have consulted cardiology rather than activating the cath lab, and treated this like a NonSTEMI. "My response: " That is not true.  It is possible that it is not posterior, but about 80-90% of the time it is posterior if the STD is maximal in V1-V4.  So if it turns out not to be, that does not mean he was right.  He was not right. "She did give nitroglycerine, and the pain improved but did not resolve, then recorded this ECG:The ST depression persists but is not as profoundI did not know this at the time, but because of a widened mediastinum on CXR, they did a CT aortogram that was negative (I use one CT image below to illustrate " posterior " MI).The first troponin I returned at 4100 ng/L -- quite high for a very acute MI, usually seen in subacute MI.Angiographic findings (done approximately 150 minutes after 1st ECG):Brisk, TIMI III flow into all coronaries. Severe distal vessel tortuos...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs