Effect of Direct Slow Pathway Capture Mapping-Guided Ablation on Typical Atrioventricular Nodal Re-Entrant Tachycardia.

Background: Direct slow pathway capture (DSPC) mapping is a novel electrophysiological technique for detecting antegrade slow pathway input sites. However, the effect of DSPC mapping-guided ablation on atrioventricular nodal re-entrant tachycardia (AVNRT) is unknown.

Objectives: This study aimed to evaluate the efficacy and safety of DSPC mapping-guided ablation in typical AVNRT patients.

Methods: A multicenter retrospective study was conducted in 301 consecutive typical AVNRT patients. The outcomes in patients who underwent DSPC mapping-guided ablation (DSPC group) and those who underwent conventional anatomical ablation (conventional group) were compared. The conventional group was established before introducing DSPC mapping-guided ablation. Positive DSPC sites were defined as sites with a return cycle atrioventricular prolongation of ≥20 ms with high-output (10-20 V) pacing during tachycardia or the last paced beat of the atrial extrastimulation.

Results: Among 116 patients in the DSPC group, 102 (88%) had positive DSPC sites, and 86 (74%) had a successful ablation at that site. Of the remaining 30 patients, 27 had a successful anatomical ablation. The DSPC group had a significantly lower frequency of radiofrequency applications and shorter total application time than the conventional group (median: 5.5 [IQR: 3-11] times vs 9 [IQR: 5-15] times, and 168 [IQR: 108-266] seconds vs 244 [IQR: 158-391] seconds, respectively; P < 0.01). Moreover, the DSPC group had a numerically lower incidence of permanent pacemaker implantations and AVNRT recurrences than the conventional group (0% vs 1.6%; P = 0.17, and 1.7% vs 3.2%; P = 0.43, respectively).

Conclusions: DSPC mapping-guided ablation was associated with a lower operative time, which can reduce the risk of AV conduction injury in typical AVNRT.