RADIOFREQUENCY CATHETER ABLATION OF ATRIAL TACHYCARDIAS

Introduction. Radiofrequency catheter ablation of atrial tachycardia g uided by bipolar activation mapping has been reported in the last year s. This article reports the use of radiofrequency catheter ablation fo r the treatment of atrial tachycardia using simultaneous bipolar and u nipolar activation mapping at our institution. Methods. Nine patients (7 male and 2 female, mean age 37.2 +/- 24.1 years), were selected for radiofrequency catheter ablation of drug refractory atrial tachycardi a. Mapping procedure included an investigation of the local earliest b ipolar and unipolar activity and unipolar morphology analysis. Results . Atrial tachycardia was successfully ablated in 7 patients (78%) with an average number of 6.8 +/- 3.1 RF pulses. Procedure related complic ations and tachycardia follow-up recurrences were not observed in any patient. Bipolar local activation time was significantly shorter at su ccessful than at unsuccessful ablation sites (-30 +/- 21.1 ms vs -18.3 +/- 20.6 ms; p = 0.01). No difference was observed in unipolar local activation time between successful and unsuccessful sites (-22.5 +/- 2 6.2 ms vs -19.8 +/- 21.5 ms; p = 0.56). Accurate localization of the s uccessful ablation site by unipolar electrogram analysis was not feasi ble because a <<QS>> pattern was found at both 21 unsuccessful and 2 s uccessful ablation sites. Finally, a fast slope of the negative deflec tion of the unipolar electrogram was found at 2 out of 45 unsuccessful and 3 out of 6 successful ablation sites. Conclusions. Radiofrequency catheter ablation of atrial tachycardia is feasible without complicat ions in most patients. Bipolar activation mapping accurately localizes the successful ablation site. A <<QS>> pattern is not predictive of s uccessful radiofrequency application.