[Electrophysiologic demonstration of dual atrioventricular nodal pathways and final common pathway in a case of A-V nodal paroxysmal tachycardia. Considerations on the functional complexity of the A-V node (author's transl)].

The AA. studied the A-V nodal conduction using the technique of induced PAB in a patient with A-V reentrant paroxysmal tachycardia. They observed that the conduction through the A-V node failed when coupling intervals A1-A2 were between 280 and 260 msec and, after, recovered, with consistent slackening, when A1-A2 intervals were shortened, until the atrial ERP was reached. This uncommon response indicates the functional complexity of the A-V node and, particularly, suggests the presence of a final common pathway distal to the fast and slow A-V pathways, that are the anatomic-functional basis of the reentry circuit in A-V nodal paroxismal tachycardia.