[The catheter ablation of atrioventricular nodal reentry tachycardia: the results of a mixed electrophysiological/anatomical technic].

OBJECTIVE: To describe the results of radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) by using a mixed electrophysiologic/anatomic mapping technique. DESIGN: Consecutive patients with AVNRT, submitted to AV node modification between November 1992 and March 1995. SETTING: Cardiology Department at an University Hospital. INTERVENTIONS: Twenty consecutive patients with AVNRT were submitted to AV node modification. The ablation technique included two sequential steps. Initially, a detailed electrophysiologic mapping was performed with the ablation catheter, positioned near the coronary sinus ostium, looking for a specific recording: fractionated atrial electrogram, suggestive "slow pathway" potential and a ratio of atrial: ventricular electrogram amplitude > 1. In case of failure, after 5 applications of radiofrequency energy, an anatomic technique was used. The fluoroscopic image, in left anterior oblique projection, was used to guide catheter progression, and the radiofrequency energy applied sequentially in the posterior (P), followed by medium (M) and anterior (A) septal areas if needed. Radiofrequency energy was applied a power of 16-36 watts for 30-60 sec. If a His bundle deflection > 0.0025 mV was recorded, energy was not applied. MEASUREMENTS AND RESULTS: Suppression of a AVNRT was initially obtained in 19 patients (95%). A mean of 8.3 +/- 6.1 energy application were required. Mean during of the entire procedure was 142 +/- 45 min and the fluoroscopy duration was 22 +/- 12 min. There were no complications. The location of successful ablation areas was: P in 15 patients, M in three and A in one. After a mean follow up of 10 +/- 6 months, two patients had recurrence of AVNRT. A second procedure was successful in the initially failed patient and in these two recurrences. CONCLUSIONS: A mixed electrophysiologic/anatomic mapping technique to perform radiofrequency catheter ablation of AVNRT was associated with high efficacy and no complications.