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

Abstract

Introduction Fast junctional rhythm (JR) during slow pathway modification for atrioventricular nodal reentrant tachycardia (AVNRT) is a predictor of serious atrioventricular block. This study investigated the boundary to avoid fast JR during ablation with three‐dimensional (3D) electroanatomical mapping in AVNRT patients. Methods and Results Participants were 129 consecutive patients with common AVNRT who received anatomical ablation to an antegrade slow pathway at our institution between August 2013 and March 2019. Successfully ablated sites with JR were evaluated in terms of distances and angles in the left and right anterior oblique views (LAO and RAO, respectively) to the proximal His bundle (His) site using 3D mapping. We divided JR by heart rate: JR1 ≥150 bpm and JR2 <150 bpm. Average age was 61 ± 16 years; 41.1% of patients were male. The distance from the most proximal His to the JR1 and JR2 site was not significantly different (11.9 ± 4.4 vs 10.7 ± 4.5 mm, P = .24). JR1 predominantly appeared closer to the left ventricle than JR2 in LAO (110.5 ± 19.1° vs 77.5 ± 18.6°, P < .01), and was more posterior from the proximal His in RAO (30.8% vs 6.8%, P < .01). The vertical line drawn down from the proximal His in the LAO view was a good indicator of JR1 appearance (sensitivity and specificity 84.6% and 81.6%, respectively). Conclusion The vertical line drawn down from the proximal His in the LAO view can be employed as a boundary to avoid fast JR during ablation in AVNRT.

Effectiveness of a 3D mapping benchmark for ablation in patients with atrioventricular nodal reentrant tachycardia

“…We reported previously that the vertical line drawn down from the most proximal His in LAO view was a good indicator for the appearance of excessively fast JRs (heart rate ≥ 150 bpm), which indicates FP or AV node, with a sensitivity and specificity of 84.6% and 81.6%, respectively. Additionally, the mean successful ablation point from the most proximal His was 11 mm in the same reports 8 . These results suggest that it would be safe to start ablation at the point of the ventricle side around 11 mm from the most proximal His on the line drawn vertically from the most proximal His in LAO view on the 3D mapping system where the ablation catheter is well fixed to the myocardium during ablation for our RF system setting (15‐30 W, 55°C limit).…”

“…In Group B, SP ablation was initiated from the tricuspid valve at the bottom level of the CS os where atrial potential was barely recorded from the distal tip of the ablation catheter; this anatomical approach has been used in previous studies 1,2 . Our method of assessing the location marker has been reported previously 8 . In brief, it was positioned 11 mm away from the most proximal His potential at a location on the perpendicular drawn from the His in a LAO 55° view on the 3D mapping system where the same A/V ratio of Group B was recorded from the distal tip of the ablation catheter (Figure 1).…”

“…Recently, three‐dimensional (3D) mapping has become one of the standard methods for catheter ablation as it yields better visualization of anatomical indexes, His and ostium of the coronary sinus (CS os), and facilitates the procedure. In December 2017, we identified the boundary line between appropriate and excessively fast JRs; in our report of those findings, we predicted the location of the final successful ablation point as a benchmark in a 3D mapping system and reported its relation to His potential 8 …”

Safe AVNRT ablation: Take it slow

“…In this issue of the Journal , Tachibana et al report on an anatomical approach to avoid fast junctional rhythms during the ablation of the slow pathway for patients with typical AVNRT. In this retrospective analysis of 129 patients who underwent ablation of the slow pathway, the distance and the angle from the proximal His bundle electrogram to the ablation site with JE in the right anterior oblique (RAO) and left anterior oblique (LAO) projection were measured using a 3D EAM mapping system.…”

“…However, we should remain vigilant to recognize the anatomical variation which may place a patient at risk for developing AV block. The work presented by Tachibana et al provides additional guidance which may further enhance the safety of AVNRT ablation and which can be readily adopted into clinical practice.…”