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Answer for January 14, 2013


This EKG illustrates a classic left bundle branch block (LBBB), and a borderline 1st degree AV block (PR is around 0.20 sec). It is generally true that (because LBBB disrupts the normal sequence of activation in the left ventricle) one needs to be cautious in interpreting ischemia and infarction in the presence of LBBB. An old EKG for comparison can be helpful for comparison.

In this case, The ST elevation from V1-V3 is characteristic of LBBB and is not ischemic (usually). ST elevation usually does not extend lateral to V3. As with RBBB, the expected Tw axis is opposite to the terminal deflection of the QRS. Thus, the T wave inversions in V5 and V6 are normal for an LBBB. Upright Tw in these leads would be suspicious for ischemia ("psudonormalization")!


NOTE: EKG's are for internal educational purposes of the University of Massachusetts Department of Family Medicine. Please do not forward without permission from Dr. Golding!




January 14 EKG