Entrainment of Ventricular Tachycardia by AV Nodal Reentrant Tachycardia

Abstract

Endocardial recordings from a patient with both sustained ventricular tachycardia and AV nodal reentrant tachycardia are presented that demonstrate spontaneous transient entrainment of ventricular tachycardia by AV nodal reentrant tachycardia. During electrophysiological catheterization, there were repeated episodes of spontaneous conversion from a wide to a narrow QRS morphology following the induction of ventricular tachycardia. With conversion from the wide to the narrow QRS, the ventricular deflection in the coronary sinus electrograms demonstrated an abrupt change in morphology, indicating a change in activation sequence at this site from the wavefront of depolarization emerging from the ventricular tachycardia circuit to a wavefront conducting over the His‐Purkinje system. However, the right ventricular apex electrogram demonstrated a constant morphology with a decrease in cycle length equal to that of the other intracardiac electrograms, indicating a constant direction of activation from the ventricular tachycardia circuit, and that ventricular tachycardia had been transiently entrained by AV nodal reentrant tachycardia. In addition, rapid atrial pacing during ventricular tachycardia narrowed the QRS and demonstrated transient entrainment of the right ventricular apex electrogram. Although transient entrainment of a tachycardia is evidence supporting reentry with an excitable gap as the probable mechanism, its demonstration has required the use of rapid pacing techniques. This case is a spontaneously occurring example of transient entrainment of one tachycardia circuit by another, a phenomenon that has not been previously described.

Widening of the QRS complex during the wide complex tachycardia: What is the mechanism?

“…9 Furthermore, since the QRS complex morphology of the WCT was identical to that of the frequent ventricular premature beats during SR (Figure 3), the VT was diagnosed for s-WCT. 2 The association between AVNRT and idiopathic VT has been described, 9,26-40 and only one case has been reported with scar-related VT. 41 Wylie et al 42 have demonstrated that dual AV nodal pathways (70% vs. 27%, p = .0001), dual AV nodal pathways with echo beats (24% vs. 8%, p = .03), and AVNRT (21% vs. 1%, p = .0002) were more common in patients with idiopathic VT. 42 Similarly, Kautzner et al 43 have shown a high incidence (15%) of concomitant AVNRT in patients undergoing idiopathic outflow VT ablation. In the current case, the f-WCT was eliminated successfully by radiofrequency ablation of the slow pathway, 44,45 whereas the ablation of VT was performed in the anterior wall of the left ventricular outflow tract (Supporting Information: Video 1).…”

“…The association between AVNRT and idiopathic VT has been described, 9,26–40 and only one case has been reported with scar‐related VT 41 . Wylie et al 42 have demonstrated that dual AV nodal pathways (70% vs. 27%, p = .0001), dual AV nodal pathways with echo beats (24% vs. 8%, p = .03), and AVNRT (21% vs. 1%, p = .0002) were more common in patients with idiopathic VT 42 .…”

Reciprocal Induction of Long RP and Wide QRS Tachycardias

“…The following associations have been reported: (1) LIVT inducing typical or atypical AVNRT, 3–5 (2) VT originating in the RVOT or pulmonary artery inducing typical or atypical AVNRT, 6–9 and (3) typical AVNRT inducing LI 10–12 or RVOT 13 VT. However, AVNRT entraining VT 14 or VT entraining AVNRT 15 is extremely rare.…”

Atrial Pacing Inducing Narrow QRS Tachycardia Followed By Wide Complex Tachycardia

“…The association of AVNRT and idiopathic VT has been described. Tachycardia inducing tachycardia is, however , a rare condition, and only one case has been reported with scar‐related VT 2 . The majority of case reports to date involve either a right ventricular outflow tract (RVOT) tachycardia or an idiopathic left ventricular tachycardia inducing AVNRT 3–7 .…”

“…The association of AVNRT and idiopathic VT has been described. Tachycardia inducing tachycardia is, however, a rare condition, and only one case has been reported with scarrelated VT. 2 The majority of case reports to date involve either a right ventricular outflow tract (RVOT) tachycardia or an idiopathic left ventricular tachycardia inducing AVNRT. [3][4][5][6][7] Wylie et al 8 have demonstrated that dual AV nodal (AVN) pathways (70% vs 27%, P = 0.0001), dual AVN pathways with echo beats (24% vs 8%, P = 0.03), and AVNRT (21% vs 1%, P = 0.0002) were more common in patients with idiopathic ventricular tachycardia, as compared with patients with structural heart disease undergoing VT ablation.…”