Search Close Search
Page Menu

Answer for November 19, 2012


This is yet another variation on right bundle branch block (RBBB) (compare with EKG 06). As before see the tall Rw in V1, although there is not much of a 'bunny ear'. As is typical for RBBB, there is a deep slurred Sw in V6. However, note that the axis is now a high left axis (-60 - -70 degrees or so - there is a deep S in lead aVF, lead I is positive (but the axis is nearly vertical)). A high left axis with a RBBB indicates the likely presence of left anterior fascicular block, LAFB (sometimes called LAHB for hemiblock).

RBBB + LAFB is sometimes called 'bifascicular block' and indicates the presence of serious conduction system disease. Key point: uncomplicated RBBB and LBBB do not change the QRS axis! Presence of an axis shift indicates something else is poresent. Also - note the Tw axes. DO NOT be dismayed if the Tw axis is not upright! In BBB (both left and right), the normal Tw axis is opposite in direction from the major terminal deflection of the QRS. Here (for example), the Tw is supposed to be inverted in V1, V2, and V3. Upright Tw's in these leads would suggest possible ischemia or infarction.



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!


  November 19 EKG