[Pseudoventricular tachycardia linked to a reciprocal antidromic rhythm from Mahaim's fibers].

A 24 year old female presented with paroxysmal pseudo-ventricular tachycardia with wide QRS complexes and complete atrioventricular dissociation. Electrophysiological studies showed a junctional tachycardia with an antidromic reciprocating rhythm. The activation involved Mahaïm nodo-ventricular fibres in the anterograde direction, the nodo-hisian pathway being the retrograde limb of the reentry pathway. The main point of interest of this case was the presence of complete atrioventricular dissociation during tachycardia, the atria remaining in sinus rhythm with the possibility of sinus capture formally excluding the diagnosis of a paraseptal Kent bundle. This reentry mechanism has been previously described and constitutes a differential diagnosis of ventricular tachycardia.