Clinical Importance of the Inferiorly Dislocated Fast Pathway in the Patients with Atrioventricular Nodal Reentrant Tachycardia

Abstract

Backgrounds: In the catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), the patients with the inferiorly dislocated fast pathway (IDF) were high risk of the inadvertent atrioventricular block. Objective: The purpose of this study is to show the effects of the IDF on the results of the catheter ablation. Methods: 43 consecutive patients with AVNRT were entered this study. Using the electroanatomical mapping system, the antegrade fast pathway entrance (AF) was detected and divided into 4 groups; outside and posterior to the triangle of Koch (TOK) (group F: n=17) and inside and the upper (group S: n=7), the middle (group M: n=5), and the lower (group I: n=14) third of the TOK. Group M and I were defined as the IDF. In all patients, anatomical slow pathway ablation was performed. Results: The dimension of the TOK was not different in all groups. The success rate of the slow pathway ablation was 100% in group F and S, but 80% in group M and 71% in Group I. During follow-up, no patient in group F, S, and M, but 2 patients in group I had a recurrence of the tachycardia. Conclusion: The patients with the IDF were not only refractory to the conventional slow pathway ablation, but also showed high rate of recurrence.