Electroanatomically estimated length of slow pathway in atrioventricular nodal reentrant tachycardia

Abstract

The length of the slow pathway (SP-L) in atrioventricular (AV) nodal reentrant tachycardia (NRT) has never been measured clinically. We studied the relationship among (a) SP-L, i.e., the distance between the most proximal His bundle (H) recording and the most posterior site of radiofrequency (RF) delivery associated with a junctional rhythm, (b) the length of Koch’s triangle (Koch-L), (c) the conduction time over the slow pathway (SP-T), measured by the AH interval during AVNRT at baseline, and (d) the distance between H and the site of successful ablation (SucABL-L) in 26 women and 20 men (mean age 64.6 ± 11.6 years), using a stepwise approach and an electroanatomic mapping system (EAMS). SP-L (15.0 ± 5.8 mm) was correlated with Koch-L (18.6 ± 5.6 mm; R2 = 0.1665, P < 0.005), SP-T (415 ± 100 ms; R2 = 0.3425, P = 0.036), and SucABL-L (11.6 ± 4.7 mm; R2 = 0.5243, P < 0.0001). The site of successful ablation was located within 10 mm of the posterior end of the SP in 38 patients (82.6 %). EAMS-guided RF ablation, using a stepwise approach, revealed individual variations in SP-L related to the size of Koch’s triangle and AH interval during AVNRT. Since the site of successful ablation was also correlated with SP-L and was usually located near the posterior end of the SP, ablating anteriorly, away from the posterior end, is not a prerequisite for the success of ablation procedures.

A safe and simple approach to avoid fast junctional rhythm during ablation in patients with atrioventricular nodal reentrant tachycardia

“…Bhaskaran et al applied RF with a power of 40 to 50 W and a maximum temperature of 70℃ using a nonirrigated catheter whereas the RF power was 15 to 30 W in our study. An investigation conducted with similar RF power to ours reported that the distance from His to successful ablation was 11.6 ± 4.7 mm, which was almost the same result as ours …”

“…Following the development of the 3D mapping system, many kinds of arrhythmic disease became easier to ablate. Although previous studies on AVNRT with and without the 3D mapping system showed the distance from the His potential to the successful ablation point, information concerning the borderline between areas of appropriate JR and excessively fast JR was not available. If the borderline could be clarified and marked on the 3D mapping system, a more precise point for the successful ablation of AVNRT could be identified, and the ablation procedure could be conducted with improved safety and success.…”

Utility of low‐dose adenosine triphosphate sensitivity in slow‐fast atrioventricular nodal reentrant tachycardia

“…Previous studies suggested that the slow-fast AVNRT patients with longer A-H interval over the antegrade slow pathway conduction had greater distance between the successful ablation site for antegrade slow pathway and His potential recording site. 16 Furthermore, it is also suggested that the longer conduction time over slow pathway needed to transverse a longer anatomical distance. 17,18 We also previously reported that the patients with 2:1 AV conduction block during AVNRT tachycardia had shorter TCL and A-H interval during tachycardia.…”

Tachycardia cycle and atrioventricular nodal conduction properties in children with supraventricular tachycardia

“…Finally, the reader suggested analysis of the AH interval during AVNRT based on age, as other data in the literature have suggested that the AH interval could be associated with the physical length of the slow pathway . Others have also suggested that the length of the slow pathway is critical to the development of AVNRT, as perhaps there is a critical “length” required for the development of tachycardia, and this length factor may explain why AVNRT is rarer in young children .…”