'AV Nodal' Reentry

AV Nodal Reentry. The classical model of “atrioventricular (AV) nodal” reentrant tachycardia suggests that the reentrant circuit is entirely within the compact AV node and that AVnodal tissue is present proximal and distal to the circuit. Recent evidence from mapping studiesand from examination of the effects of curative procedures, however, suggests that the upperend of the circuit uses perinodal atrial or transitional tissue. Moreover, the anatomical suhstrate of dual “AV nodal” pathways is likely to be the multiple connections between compactAV node and atrium rather than discrete intranodal pathways. The antegrade slow pathwayappears to he situated at the posteroinferior approaches to the AV node in the region betweenthe coronary sinus orifice and the tricuspid annulus, The retrograde fast pathway appears lobe situated in the anterior atrionodal connections at the apex of Koch's triangle, close tothe His bundle. The lower turnaround point of the circuit is likely to be within the AV node.