Fig. 1

Examples of QRS and T-wave morphologies in left bundle branchblock (LBBB). Mid-QRS notching (a) or slurring (b) in lead V5; QS (c) or rS (d) patterns in lead V1; concordant (e) or discordant (f) T-wave and QRS complex in leads V5 or V6. Abbreviations: LBBB left bundle branch block