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Case #40

You are called to the ER for your next admission. It is a 80 year old from a nursing home. She has past medical hx of HTN, high cholesterol, Peripheral Vascular disease, and is being sent in for change in mental status. You call the attending in charge of the nursing home and he tells you that starting this morning she became delirious. He tells you some tests he did over the last month. She had an X-ray for a cough two days ago which was clear, a colonoscopy which was negative, and had a routing EKG with LBBB block present. He is not really sure why she had a sudden change in mental status. When you approach her she is confused and delirious and basically the history is worth nothing.

Her vitals are stable, she is 96% on room air. On physical exam her pertinent positives are copious sweat, some crackles at the left lower base, an S3 and also looks dry. Her Chest X-ray is negative, and this is her EKG. Is the answer there?

Click here for Better Quality Image of the EKG

 

This is a great example of an EKG which could have easily been glossed over because of the presence of Left Bundle Branch Block. But in actuality here is the reason why she is having a change in mental status, SHE IS HAVING AN ACUTE MI !

The teaching used to be that in the face of a Left Bundle Branch Block you could not call acute MI. However, after the GUSTO investigators went back and looked at all their patients with Left Bundle Branch Block they found that if certain criteria where met on the EKG than the diagnosis of acute MI could be made. The table below is from the article in the NEJM showing the criteria they found to be most sensitive.

N Engl J Med 1996; 334:481-487, Feb 22, 1996

Basically, concordant means, the ST elevation is going in the same direction as the QRS vector, meaning if the qrs is negative and there is st elevation that is discordant You need at least a score of 3 to call it an MI. Our patient had ST elevation in II, III, AvF concordant with the QRS vector to a max of 2 mm deviation. So she had the first criteria, with a score of 5, automatically meeting criteria for MI. So next time you see that patient in the ER and there is a Left Bundle present, do a real quick check for these three criteria, just like you would check the ST segments on an EKG with out a Left Bundle, and make sure there is no acute event is going on.