We describe the case of a patient who has a right atrial tachycardia and atrial fibrillation who was found to have a single site responsible for both. We recorded a tachycardia from this site with exit block into the remainder of the atria.

We report a patient with symptomatic AV block associated with conduction solely through an atriofascicular pathway that inserted into the left bundle branch. There was no apparent conduction present through the AV node. There was, however, passive activation through the His-Purkinje system. His-bundle pacing demonstrated normal conduction through both right and left bundles. This is the first report of such a case.