Participation of fast and slow A-V nodal pathways in tachycardias complicating the Wolff-Parkinson-White syndrome. Report of a case.

Abstract

Electrophysiologic studies in 1 patient with type B pre-excitation and dual A-V [atrioventricular] nodal pathway revealed several types of paroxysmal narrow QRS tachycardia (PSVT). One type of PSVT reflected antegrade fast A-V nodal pathway and retrograde anomalous pathway conduction. This PSVT was characterized by early retrograde activation of right atrial appendage, P following QRS and cycle length of 290 to 350 ms. A 2nd PSVT reflected antegrade slow A-V nodal pathway and retrograde anomalous pathway conduction. This PSVT was characterized by early retrograde activation of right atrial appendage, P following QRS, and cycle length of 440 ms. A 3rd PSVT reflected A-V nodal re-entrance with antegrade slow pathway and retrograde fast pathway conduction. This PSVT was characterized by normal retrograde atrial activation sequences, P simultaneous with QRS, and cycle length of 320 ms. All PSVT inductions could be explained in terms of antegrade and retrograde properties of fast and slow A-V nodal and anomalous pathways.