Wide Complex Tachycardia Due to Automaticity in an Accessory Pathway

Abstract

Patients with the Wolff-Parkinson-White (WPW) syndrome have preexcited tachycardia as the result of atrial arrhythmias or antidromic reentry. This article describes a patient with persistent wide complex tachycardia due to abnormal automaticity in the accessory pathway. Radiofrequency catheter ablation resulted in simultaneous elimination of accessory pathway conduction and automaticity. Accessory pathway automaticity may be an infrequent cause of preexcited tachycardia in patients with the WPW syndrome.

Ablation of a symptomatic spontaneous automatic focus arising from an atriofascicular fiber

“…Complete elimination of automatic activity has been proposed to represent a hallmark for successful ablation of atriofascicular pathways. Some investigators have proposed that simultaneous elimination of AP conduction and automaticity by a single discrete lesion indicates that the same tissue is implicated in AP conduction and such an automatic response 18, 19. In our case, disappearance of AP conduction, elimination of the spike potential, and the absence of induced RBB block suggest that the PVCs originated from the AP/insertion site rather than from the more distal His-Purkinje system.…”

Wide QRS Complex Tachycardia in a Patient With Concealed Accessory Pathway: What Is the Mechanism?

“…Reports describing spontaneous activity in accessory pathways mainly deal with atriofascicular pathways; due to AV‐node‐like physiology, these pathways not infrequently show spontaneous and heat‐induced automaticity . However, we found only four reports concerning manifest automaticity in a regular atrioventricular AP . Compared with these patients, ours is unique in 2 ways.…”

Automaticity with anterograde conduction of a concealed accessory pathway due to radiofrequency energy application

“…Accelerated automatic rhythm is also a well-known response of atriofascicular pathways to thermal injury during RF ablation being another argument for the presence of an AV nodal-like structure in atriofascicular pathways. What is very uncommon is the occurrence of automaticity of rapidly conducted APs in response to RF energy application [1][2][3]. In our case two different wide QRS complex rhythms, one regular (Fig.…”

“…Automaticity of rapidly conducting atrioventricular accessory pathways (AP) in response to radiofrequency (RF) energy application is a very uncommon observation [1][2][3]. On the other hand, emergence of ventricular preexcitation following RF application in concealed accessory pathways is one other rare electrophysiologic phenomenon that has been previously reported, the mechanism of which is poorly understood [4,5].…”