-- QRS > 0.12 sec in Limb leads; 
-- Note: w/ LBBB, MI can't be accurately; dx'ed on EKG; (can't identify the Q waves) 
-- Note: the mean QRS Vector and Vent. Hypertrophy Can't be accurately calculated in the presence of B.B.B. 
-- May represent (pending) MI; 
- Right B.B.B. (V1,2) Left B.B.B. (V5,6) Lft. V. / Rt. V. Rt.V. // Lft.V. / /  /  __/  / __ /   / __/ __ / 
- RR in V1, V2 
- RR in V5, V6, (I & aVL) 
- S wave in Lead I, V6, & aVL 
- Loss of normal Q's: I, aVL, V6 
- may result from Ant MI 
- Complete LBBB lesion, Axis >  
- 45 
- may occur w/ Ant Hemiblock 
- QS complex in V1, V2 
- Loss of R in V1, V2; 
- Right bundle branch block can occur during passage of the Swan catheter through the right heart; 
- in a patient with preexisting left bundle branch block, this condition can lead to complete heart block. 
- in patient w/ left bundle branch block, transvenous pacing catheter should be be available