Multiple Shifts of the Earliest Retrograde Atrial Activation Site Along the Tricuspid Annulus During the Fast-Slow Form of Atrioventricular Nodal Reentrant Tachycardia by Radiofrequency Modification

Abstract

A 70-year-old woman was admitted for treatment of supraventricular tachycardia. Ventriculoatrial conduction was revealed through programmed ventricular stimulation; the coronary sinus ostium (CSos) was the earliest atrial activation site. The fast-slow forms of atrioventricular nodal reentrant tachycardia (AVNRT) were induced by ventricular extra-stimuli. During tachycardia, the earliest atrial activation site was located at the bottom of CSos. Radiofrequency (RF) energy application to this site resulted in the delay of local electrical potential, prolongation of tachycardia cycle length, and a shift of the earliest retrograde activation site to the roof of CSos. Subsequent ablation induced a similar shift to the inferior tricuspid annulus and to the right posterior septum. Finally, RF energy application to the right posterior septum resulted in the termination of tachycardia, which was not induced afterward. Multiple shifts in the earliest retrograde atrial activation site along the tricuspid annulus after each slow pathway ablation suggested that annular tissue plays a substantial role as a substrate for AVNRT.

A narrow QRS tachycardia with an atrial sequence not identical to that during ventricular pacing: What is the mechanism?

“…Second, there must be some type of communication from the AV node to this right lateral region. Multiple shifts in the earliest atrial activation site via the retrograde slow pathway have been reported in previous reports 3,4 . A recent histological report hypothesized that there is the presence of specialized conduction tissue along the atrioventricular (AV) rings, which anatomically comprises the AV septum and annulus of the tricuspid and mitral valves 5 .…”

Atrioventricular Ring Tachycardias: Atypical Fast-Slow Atrioventricular Nodal Reentrant Tachycardia and Atrial Tachycardia Share a Common Arrhythmogenic Substrate—A Unifying Proposal

“…An accelerated junctional rhythm developing during ablation may be due to heating of the AV nodal transitional cells constituting these SP [ 58 , 63 ]. However, in some patients, the tachycardia may be refractory, requiring the delivery of multiple radiofrequency applications due to shifts of the site of earliest atrial activation during tachycardia after each application [ 58 , 59 ], similar to the observations made during ablation of superoanterior SP described earlier. This may also indicate the presence of a relatively wide SP with multiple connections into the atrial muscle [ 58 ].…”

“…Convinced of our diagnosis of fast-slow AVNRT, we named “inferolateral right atrial SP” this variant of SP with a breakthrough in the inferolateral right atrium. No other similar case has been reported except a single case report from a Japanese institution [ 59 ], probably because three-dimensional electroanatomical activation mapping to identify the site of earliest atrial activation during fast-slow AVNRT has been used by only a few electrophysiologists [ 60 ]. Recent anatomical studies have described a right inferior extension of the AV node into the cavo-tricuspid isthmus [ 56 ].…”

Antegrade slow pathway mapping of typical atrioventricular nodal reentrant tachycardia based on direct slow pathway capture

“…In this study, all ASps were located at the anatomical slow pathway region. However, slow pathway is sometimes located at the mitral annulus, tricuspid annulus, and non‐coronary cusp of Valsalva 23‐27 . In such cases, whether or not our method worked well was uncertain.…”

“…However, slow pathway is sometimes located at the mitral annulus, tricuspid annulus, and non-coronary cusp of Valsalva. [23][24][25][26][27] In such cases, whether or not our method worked well was uncertain.…”