CATHETER ABLATION OF VENTRICULAR-TACHYCARDIA IN PATIENTS WITH RIGHT-VENTRICULAR DYSPLASIA - IDENTIFICATION OF TARGET SITES BY ENTRAINMENT MAPPING TECHNIQUES

Objective: To identify target sites for radiofrequency ablation of ven tricular tachycardia (VT) by entrainment mapping techniques in patient s with arrhythmogenic right ventricular dysplasia. Methods: Entrainmen t mapping and radiofrequency ablation of eight VTs was performed in se ven patients. Radiofrequency ablation was applied at 31 reentry circui ts sites that were classified based on findings during entrainment. Re sults: By entrainment criteria the 31 sites were classified as: exit s ites (n = 12), proximal sites (n = 6), and outer loop sites (n = 13). Radiofrequency current application terminated VT at 7 of 31 sites: 2 o f 12 exit sites (17%), 4 of 6 proximal sites (67%), and 1 of 13 outer loop sites (8%). Conclusion Radiofrequency ablation terminated VTs mos t often at sites proximal to the exit as opposed to outer loop sites a nd exit sites (P = 0.05). The critical isthmus for ablation of VT in r ight ventricular dysplasia often may be distant to the exit.