Right Bundle Branch Block
When you interpret the Right Bundle Branch Block you first STATE the Underlying Rhythm. For Example: Sinus Bradycardia with a Right Bundle Branch Block

Left Bundle Branch Block
When you interpret the Left Bundle Branch Block you first STATE the Underlying Rhythm. For Example: NSR with a Left Bundle Branch Block
Note how the Left BBB often has a more 'blunted' or 'stubby' look.
EKG Page