Complete right bundle branch block

The initial myocardial activation is normal; thus, there is a normal septal q wave in leads 1 and V6, followed by a tall R wave. Similarly, there is a normal initial septal R wave followed by a deep S wave in leads aVR and V1. However, the subsequent abnormal right ventricular activation occurs from left to right and goes through the ventricular myocardium instead of the His-Purkinje system; thus, there will be a tall and broad secondary R wave (R') in leads aVR and V1 (a RSR' complex), and a deep and broad S wave in leads I and V6. The width of the QRS complex is >0.12 sec.