Abstract 13047: Clinical Importance of the Inferiorly Dislocated Fast Pathway in Patients With Atrioventricular Nodal Reentrant Tachycardia
Backgrounds: In the catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), inadvertent atrioventricular block (AVB) occured at about 1% of the patients, and many of those were thought to have the inferiorly dislocated fast pathway (IDF).
Objective: The purpose of this study is to show the incidence of the IDF and its effects on the results of the catheter ablation.
Methods: 43 consecutive patients with AVNRT were entered this study. Using the electroanatomical mapping system, the fast pathway entrance (AF) was defined as the point of shortest stimulus-His interval during constant pacing from the mapping catheter. The sites of the AF were divided into 4 groups; outside and posterior to the triangle of Koch (TOK) (Group F:n=17, 29% men, mean age 54±18 years) and inside and the upper (Group S:n=7, 43% men, mean age 46±13 years), the middle (Group M:n=5, 60% men, mean age 46±14 years), and the lower (Group I:n=14, 36% men, mean age 56±16 years) third of the TOK. Group M and I were defined as the IDF. To all patients, anatomical slow pathway ablation to the right posteroseptum were performed, starting at the bottom or middle level of coronary sinus ostium.
Results: In this study group, the IDF was shown in 44%. The dimension of the TOK was not different in each group. During energy application, significantly higher incidence of transient AVB and/or junctional tachycardia (JT) with ventriculoatrial block (VAB) was shown in the IDF (24%, 14%, 40%, and 71% in Group F, S, M, and I, respectively (P=0.028)), but no patient showed permanent AVB. Minimal cycle length of the JT during energy application was not significantly but prone to be shorter in the IDF (456±138ms, 428±96ms, 396±225ms, and 355±91ms in Group F, S, M, and I, respectively (P=0.1367)). 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 a mean follow-up interval of 9.4 month (rage 0.5 to 17), no patient in Group F, S, and M, but 2 patients(14%) 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.
- © 2011 by American Heart Association, Inc.