Tachycardia caused by an accessory nodoventricular tract: a clinico-pathologic correlation

Abstract

Paroxysmal tachycardia with widened QRS complexes was recorded in an eleven-year old boy who had suffered from brain damage, which had resulted from an episode of ventricular fibrillation. Atrial stimulation produced an increased AV conduction, sudden disappearance of the His bundle deflection and a complete left bundle branch block pattern. Tachycardias of this morphology were initiated by early atrial and ventricular premature beats. The findings suggested the presence of a macro re-entry circuit, utilizing a slow AV node- nodoventricular bypass tract as the anterograde limb and the His-Purkinje system--fast AV node as the retrograde limb. This supposition found further support by serial sectioning of the AV junctional area of the heart, which revealed a nodoventricular tract, which originated from the posterior extension of the compact part of the atrioventricular node and inserted into the crest of the ventricular septum.

The electrocardiogram during sinus rhythm and tachycardia in patients with Mahaim fibers

“…Our patients with variable expression of preexcitation did not have long refractory periods of their accessory pathway. There is one case report of sudden death in a patient with similar findings (24). Conduction over Mahaim fibers can be so slow that no Sternick et al October 19, 2004October 19, :1626 The ECG in Patients With Mahaim Fibers ventricular preexcitation occurs even during atrial pacing.…”

Entrainment Mapping of a Concealed Nodoventricular Accessory Pathway in a Man with Complete Heart Block and Tachycardia‐Induced Cardiomyopathy

“…Reports of true nodoventricular (NV) or nodofascicular (NF) APs are rare (e.g., Refs. 10–16, reviewed by Sternick and Wellens 17 ), and even some of these remain controversial 9 . We present an unusual case of tachycardia‐induced cardiomyopathy related to frequent episodes of orthodromic NV reciprocating tachycardia (ONVRT) in a patient with complete heart block.…”

Cardiac Mapping in Variants of the Ventricular Preexcitation Syndrome

“…Since the 1980s, when it became clear that the majority of the previously called nodoventricular fibers were in reality atriofascicular pathways, some authors even doubted the very existence of such structures. In the last 25 years we have learned that nodoventricular and nodofascicular fibers do exist, but only a few well-studied cases were reported [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. Nodoventricular fibers were recently described in the autopsy of a patient who had a PRKAG2 gene mutation.…”

“…The differential diagnosis between an AVNRT and a tachycardia using a concealed nodofascicular (NF) fiber can be difficult [75]. Factors that favor a Mahaim NF fiber include: 1 intermittent anterograde preexcitation [64] 2 absence of His-bundle activation when the tachycardia is initiated by ventricular extrastimuli [76] C H A P T E R 2 4 Mapping in Variants of the Ventricular Preexcitation Syndrome 3 tachycardia initiation with a single atrial premature beat producing a dual ventricular response (1: 2 A:V) [76] 4 increase in the tachycardia cycle length at the occurrence of bundle branch block [65] 5 ability of a ventricular extrastimulus during His-bundle refractoriness to advance the next His bundle activation [68] 6 reproducible termination with adenosine supports participation of the AV node as the anterograde limb in the tachycardia circuit 7 catheter ablation of the AV node or the Mahaim fiber with elimination of the tachycardia (Figure 24.38). Intra-Hisian reentry may occur in a diseased His bundle, with prolongation of the HV interval and the occurrence of a split His potential.…”