A dual nodal response to the parahisian pacing and induction of the retrograde right bundle branch block maneuvers.

We presented intracardiac electrograms during the parahisian pacing, which represent three types of retrograde conduction and focus on the mechanism of types of retrograde conduction on wide QRS complexes and conclude that the two types of QRS of the retrograde conduction resulted from the presence or absence of retrograde block at the right bundle branch.