If I understood it correctly, the interesting article above discusses the effect of antegrade concealment on retrograde conduction. However, as you know that does not apply in fusion, where the AVN, and the rest of the conduction system, has to be fully activated antegradely (not just concealed), so it is not plausible to assume its involvement again in retrograde direction. Again, the possibility of a retrograde only pathway (especially with decremental conduction) can not be excluded, although unlikely here.

I doubt this is a CRT with that long PR and wide QRS like you pointed out. May be Naser can clarify the nature of the device.