Interesting Left Main Occlusion....

Many believe that left main occlusion results in diffuse ST depression with ST elevation in aVR.  This is not true, as I write about in this post: The difference between left main occlusion and left main insufficiency. This patient presented with ischemic symptoms:There is diffuse ST depression, with ST elevation in aVR.This is consistent with coronary insufficiency, but not coronary occlusion.It could be a tight left main, or a tight LAD, especially with 3-vessel disease.Such patients have about a 50% chance of needing CABG, as shown in an article referenced and described in this post.  Therefore, Plavix (clopidogrel) should be avoided.The patient was taken for emergent angiogram:This is an angiogram of the left main, and it is totally occluded.How is that possible?  Why is the patient alive?  And why is there ST depression of subendocardial ischemia rather than ST elevation of anterior, lateral, and posterior walls?Why is this not a STEMI?The answer lies in the RCA angiogram:The distal RCA is seen on the left side of the image (we do not see the catheter or the injection at the ostium of the RCA. There are right to left collaterals which supply the left system with enough flow to keep the patient alive and to prevent subepicardial ischemia (STEMI).  All of the flow seen on the right side of the image is flow in the LAD and circumflex that is supplied by the RCA collaterals.The left main was opened and the patient did well.Most left main oc...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs