Propagation of the Sinus Impulse Into the Koch Triangle and Localization, Timing, and Origin of the Multicomponent Potentials Recorded in This Area

Abstract

Background-The presence of a conduction block at the level of the Koch triangle (KT) and the origin of the multicomponent potentials inside this area are controversial issues. We investigated the propagation of the sinus impulse into the KT and the characteristics of multicomponent potentials recorded in that area in patients with and without atrioventricular nodal reentrant tachycardia (AVNRT). Methods and Results-Thirty-two patients (16 with AVNRT, 16 without AVNRT) underwent a sinus rhythm electroanatomic mapping of the right atrium (RA). Conduction velocities in the RA and in the KT were evaluated quantitatively on activation maps and qualitatively on isochronal and propagation maps. The presence, location, and timing of different types of multicomponent potentials were evaluated. A mean of 149Ϯ44 points were sampled in the RA, whereas a mean of 79Ϯ21 points were collected inside the KT. Propagation block at the level of crista terminalis was not found in any patient, whereas slow conduction inside the KT was found in all (

Propagation Mapping Wave Collision Correlates to the Site of Successful Ablation During Voltage Mapping in Atrioventricular Nodal Reentry Tachycardia

“…[2][3][4] Consistent with previous studies on AVNRT, as multiple wave fronts approach from different directions, it would be expected to cause a wide, fractionated, low-voltage electrogram. 5,6 Other studies have shown alterations in timing, electrogram amplitude, and His-bundle appearance in the perinodal area, depending on the fast-or slow-pathway conduction. In particular, Zhang showed that the transition from fast-pathway conduction to slowpathway conduction was associated with the formation of different wave fronts with the TK.…”

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

“…During sinus rhythm the node is most commonly activated from the direction of the anterior limbus of the fossa ovalis, but activation can also be seen from the inferior interatrial septum, from the region of the coronary sinus ostium within the triangle of Koch. Both contact and non-contact three-dimensional mapping techniques [2] have been used to demonstrate these distinct wavefronts of activation. These studies have also shown the tendon of Todaro to act as a barrier to impulse propagation.…”

“…Pandozi et al [2] recently described activation of Koch's triangle by independent wavefronts propagating from the apex and the base of the triangle. These wavefronts collided within the triangle, the collision point always occurring in its inferior portion.…”

The “Slow Pathway” Potential: Fact or Fiction?

“…In this issue of Circulation: Arrhythmia and Electrophysiology, Pandozi et al 9 report their observations on detailed sinus rhythm propagation maps into the critical regions surrounding the compact AVN and the atrial inputs to the AVN. In 32 patients (26 with AVNRT), the high-density maps of Koch's triangle in sinus rhythm in their analysis revealed no evidence of propagation block and widespread evidence of slow conduction throughout this region.…”

“…They also describe hybrid electrograms with characteristics of both these signals. 5,9,16 The exact interpretation of what these signals represent mandates perfect assessment of the anatomic location of the TT. If one uses the construct that the fast pathway exit is behind the TT whereas the slow pathway and compact AVN are in front of (closer to the tricuspid valve) the TT, 6 and if the line of block or slow conduction is the TT, then when a catheter is placed in front of the TT, in sinus rhythm, there will be delayed activation of this site representing slow pathway conduction.…”