Multiple AV nodal pathways in patients with AV nodal reentrant tachycardia — more common than expected?

Abstract

The incidence of more than two AV-nodal pathways in patients with AVNRT was unexpectedly high at about 40%. Thus, these tachycardias require a meticulous electrophysiological evaluation for successful ablation.

Atrioventricular Nodal Reentrant Tachycardia

“…Electrophysiological behavior compatible with multiple pathways may also be seen, 4 and in some patients, several forms of AVNRT may be inducible at electrophysiology study. 3,5 Heterogeneity of both fast-and slow-conduction patterns has been well described, and all forms of AVNRT may display anterior, posterior, and middle retrograde activation patterns (Table).…”

“…3,5 Heterogeneity of both fast-and slow-conduction patterns has been well described, and all forms of AVNRT may display anterior, posterior, and middle retrograde activation patterns (Table). 4,[5][6][7] In certain cases of atypical AVNRT, retrograde atrial activation is even suggestive of a left lateral accessory pathway. 8 -10 Appropriate diagnosis in this setting is of importance for the avoidance of prolonged procedures with high fluoroscopy times and unnecessary radiofrequency lesions.…”

“…Although typically, the earliest retrograde atrial activation is recorded at the His bundle electrogram, careful mapping studies have demonstrated that posterior or even left septal fast pathways may occur in up to 7.6% of patients with typical AVNRT. 4,6,7,12,13 The possibility of a bystander atrionodal pathway 12 cannot be ruled out in all cases, but studies of left septal mapping indicate that if left septal His recordings were routinely performed in patients with AVNRT, left-sided retrograde fast pathways would be documented in a considerable proportion of patients studied ( Figure 3). 14 after ventricular activation, with an AH/HA ratio Ͻ1, which indicates that retrograde conduction is slower than antegrade conduction.…”

New Insights into Reentry Circuits from Mapping and Ablation of Atrioventricular Nodal Reentrant Tachycardia

“…Rather there may be multiple functional slow pathways, evidenced by the presence of multiple discontinuities in the AV node antegrade or retrograde function curves. Heinroth et al [6] reported dual AV nodal physiology with a single antegrade slow pathway in 60% of patients with inducible AVNRT, evidence of two antegrade slow pathways in 35% and evidence of three antegrade slow pathways in 5%. They reported an increased incidence of multiple forms of AVNRT in patients with multiple antegrade slow pathways, but multiple forms of AVNRT were still seen only in a minority of such patients.…”

Narrow QRS Tachycardia with 1:1 VA Conduction and Irregular Cycle Length: What Is the Mechanism?

“…The prevalence of multiple AV nodal pathways in patients with AVNRT has been described to be between 5% and 40% 2,3 . Luzza et al 4 reported about an AVRT with a left lateral concealed accessory pathway and a dual AV node as the anterior pathway.…”