LV aneurysm (persistent ST elevation after previous MI) in the setting of RBBB

65 yo male with recent rule out presents with unrelated complaint but also states he is SOB.

What are the worrisome EKG findings, and what is the differential diagnosis? What is the most likely diagnosis? What info would you like to have to make a decision?

LV aneurysm with Right Bundle Branch Block

This is a really hard one. But we had a patient 10 years ago who received tPA twice for an EKG like this before we reali zed that it was old MI with persistent ST elevation. LV aneurysm (persistent ST elevation after old MI) usually has no (or minimal) R-wave. But RBBB automatically provides an R' wave, which makes it difficult to realize that the anterior wall is dead. Additionally, RBBB with acute MI can look very similar. That is why, before you diagnose RBBB with acute MI, you should see if there is a previous EKG. In this case, the previous EKG was found and looked pretty identical. Previous echos confirmed dense anterior, septal, and apical wall motion abnormality with akinesis (I don't think there was dyskinesis).