Electrophysiologic Characteristics of Ventricular Extrastimulation‐Induced Dissipation of Functional Bundle Branch Block Associated with Supraventricular Tachycardia

Abstract

During SVT, functional bundle branch block due to "linking" often can be dissipated by timely PVB delivered from the right ventricular apex within a narrow zone of the tachycardia CL. Our findings suggest that the dissipation zone is affected by the pattern of functional bundle branch block relative to the site of PVB delivery.

Effects of right bundle branch block during atrioventricular nodal reentrant tachycardia

“…In the present study, transient RBBB occurred after introducing a short burst of right ventricular pacing; these findings suggested that the retrograde concealment of ventricular impulses in the His-Purkinje might account for the occurrence of transient RBBB [2,5]. Li et al used a quantitative model to demonstrate that the lower turnaround point of AVNRT circuit was above the His-bundle in more than half of the 70 patients with AVNRT [15].…”

“…This phenomenon occurs much more frequently during orthodromic reentrant tachycardia than AV nodal reentrant tachycardia (AVNRT) [1][2][3][4][5]. To our knowledge, few studies have reported the effects of bundle branch block during AVNRT.…”

Transient aberrancy during AV nodal reentrant tachycardia: What is the mechanism?

“… 2 Moreover, a subsequent premature ventricular extrastimulus (S2) at a higher pacing‐output, with manifest local ventricular capture, terminated the aberrant conduction. The premature ventricular depolarization (S2) likely also captured the RBB pre‐exciting it before concealed conduction could occur, and thus peeling back its refractoriness 3 . Accordingly, the last extrastimulus (S2) could interrupt the linking between bundle branches due to a “reset effect” (Figure 2D), while the relative RR prolongation at the following return beat allowed full recovery of excitability of both branches during the ongoing tachycardia and thus abolishing the aberrant conduction (Figure 2E).…”