Anterograde Slow Pathway Is Not the Same as Retrograde Slow Pathway Conducted in the Reverse Direction in Patients with Uncommon Atrioventricular Nodal Reentrant Tachycardia

Abstract

Slow Pathways in Uncommon AVNRT. Introduction: The aim of this study was to examine the location of anterograde and retrograde slow pathways in 16 patients with uncommon atrioventricular nodal reentrant tachycardia (AVNRT), including the fast-slow form in 10, slow-slow form in 5, and both fast-slow and slow-slow forms in 1.Methods and Results: Patients were divided into two groups according to the approach used for slow pathway ablation in the initial radiofrequency catheter ablation (RFCA): one approach used earliest atrial activation during tachycardia (ES group, n = 9), and the other used a slow potential during sinus rhythm (SP group, n = 7). When the initial RFCA failed to eliminate slow pathway conduction in the ES group, an additional RFCA guided by a slow potential was performed. The ratio of lengths from the His-bundle region to the RFCA site and coronary sinus ostium (Abl/His-CS ratio) and the ratio of amplitudes of atrial and ventricular potentials at the RFCA site (A/V ratio) were compared between the two groups. In the initial RFCA, retrograde slow pathway conduction was eliminated without impairment of anterograde slow pathway conduction in 8 (89%) patients from the ES group, and bidirectional slow pathway conduction was eliminated in 6 (86%) patients from the SP group. Residual anterograde slow pathway conduction that was preserved after the initial RFCA in 8 of 9 patients was eliminated by an additional slow potential-guided RFCA. Both the Abl/His-CS ratio (0.86 ± 0.07 vs 0.73 ± 0.11, P = 0.01) and A/V ratio (0.80 ± 0.31 vs. 0.14 ± 0.01, P < 0.001) were higher in the ES group than the SP group. The ratios for the residual anterograde slow pathway ablation in the ES group were similar to those in the SP group.Conclusion: The results of this study suggest that the retrograde slow pathway runs more on the atrial side of the tricuspid valve annulus at the level of the coronary sinus ostium compared with the anterograde slow pathway, although both pathways run parallel or are fused in portions more proximal to the His bundle.

Pacemaker‐Like Syndrome Complicating Slow Pathway Ablation for AV Nodal Reentrant Tachycardia

“…8 Ooie et al suggested that the retrograde slow pathway travels more on the atrial side of the tricuspid valve annulus at the level of the coronary sinus ostium compared with the anterograde slow pathway, although both pathways run parallel or are fused in portions more proximal to the His bundle. 9 This may account for the selective ablation of the anterograde slow pathway in our patient with preservation of retrograde slow pathway conduction. In…”

Analysis of Atrioventricular Nodal Reentrant Tachycardia with Variable Ventriculoatrial Block: Characteristics of the Upper Common Pathway

“…A shift in retrograde conduction from the fast to slow pathway implies the existence of multiple slow pathways. Previous reports suggested that the antegrade slow pathway is anatomically distinct from the retrograde pathway 2,27,28 . Ino et al reported a similar case that showed a shift in retrograde conduction just before VA block and transient prolongation of the HH interval during VA block 21 .…”

“…Previous reports suggested that the antegrade slow pathway is anatomically distinct from the retrograde pathway. 2,27,28 Ino et al reported a similar case that showed a shift in retrograde conduction just before VA block and transient prolongation of the HH interval during VA block. 21 They suggested that such prolongation of the tachycardia cycle length is due to the presence of a third reentrant circuit in which the retrograde impulse turns around more slowly.…”

A case of typical atrioventricular nodal (AVN) reentrant tachycardia confined to the compact AV node, showing a variety of rare electrophysiological findings, including eccentric AVN echoes

“…Judging by these findings, sites impaired by ablations could be determined to include the antegrade slow and very slow AVNPs, and the retrograde fast AVNP but not the retrograde slow AVNP (Fig. 4B) [9]. The programmed stimulation from the HRA performed with Isp infusion after RFA delineated a smooth AV conduction curve and did not produce Ae because of further facilitation of conduction over the antegrade fast pathway (not shown in the figure).…”