Utility of nonfluoroscopic three-dimensional electroanatomical mapping in accessory pathways with prior unsuccessful ablation attempts.

Three-dimensional electroanatomic mapping was performed to guide radiofrequency catheter ablation in 17 patients with accessory pathways (APs) who had undergone 2.0 +/- 0.9 previous unsuccessful conventional procedures. In 14 patients, activation mapping was directed at the atrial insertion of the bypass during tachycardia (6 patients) or right ventricular pacing (7 patients) or by mapping atrial stimulus-delta-wave intervals. The ventricular insertion of the bypass was mapped and targeted for ablation in the remaining 3 patients. Successful AP ablation was obtained in all but 1 patient (94%) after a mean of 8 +/- 7 radiofrequency pulses, without recurrences during a mean follow-up of 16 +/- 15 months. On the basis of mapping results and successful ablation outcomes, the most likely causes of previous failed ablation attempts were anatomic or mapping reasons (13 patients), catheter manipulation-related problems (2 patients), and miscellaneous reasons (1 patient).