1. Left Bundle Branch Block and Intermittent Type A Preexcitation
Pablo Denes, M.D., Paul Goldfinger, M.D., Kenneth M. Rosen, M.D., F.C.C.P. 
CHEST 
Volume 68, Issue 3, Pages (September 1975)
DOI: /chest
Copyright © 1975 The American College of Chest Physicians Terms and Conditions

2. Figure 1
Intermittent type A preexcitation with complete left bundle branch block. Electrocardiographic leads, V1-V6 are shown. QRS complexes showing type A preexcitation are labeled A, and those showing complete left bundle branch block, LB. Note that the QRS complexes with preexcitation are narrower and the left bundle branch pattern is masked.
CHEST  , DOI: ( /chest )
Copyright © 1975 The American College of Chest Physicians Terms and Conditions