There was a discussion regarding LBBB and MI at lecture. Although guidelines have changed, they really haven’t. Like most chest pains – treat the pt, not the ekg, and this is particularly apropos in LBBB, because the ekg becomes somewhat immaterial (it is difficult to interpret the usual ischemia findings of ST elev and ST depr in LBBB).
http://www.acc.org/latest-in-cardiology/articles/2017/02/28/14/10/lbbb-in-patients-with-suspected-mi
This article is identical to what I do. When there are ST elevations in leads where QRS is upright (“concordant”), push the ME-HEART button. Everyone else, call Cards if the story is good enough. This is what we did 20 years ago as well when LBBB was a potential indication for thrombolytics.