Role of Isoproterenol in Predicting the Success of Catheter Ablation in Patients with Reproducibly Inducible Atrioventricular Nodal Reentrant Tachycardia

Noninducibility of the arrhythmia is the widely accepted endpoint of successful ablation of atrioventricular nodal reentrant tachycardia (AVNRT). However, to rely upon that as the only endpoint, the arrhythmia must also be inducible before ablation. Despite the fact that AVNRT is not reproducibly inducible in a significant number of cases, the role of reproducible arrhythmia induction and its relationship with the infusion of isoproterenol after successful ablation of AVNRT has not been well defined. We studied 175 consecutive patients who all underwent successful radiofrequency ablation after showing that they had reproducibly inducible AVNRT without use of isoproterenol. In Group 1 (n=90), isoproterenol was used for arrhythmia reinduction after ablation, whereas in Group 2 (n=85) it was not. The procedural and follow-up data of both groups were recorded, and the results of appropriate statistical tests were analyzed. During a mean follow-up time of 18.7 ± 4.5 months, 4 patients in Group 1 and 3 patients in Group 2 experienced recurrences. Regardless of elimination or modification of slow-pathway conduction, no significant difference was seen in the recurrence rates of AVNRT between the 2 groups (P=0.72). We conclude that, when the original arrhythmia in patients with AVNRT is reproducibly inducible in the basal state, the use of isoproterenol after ablation in order to confirm the noninducibility of AVNRT does not appear to alter the recurrence rates and can be omitted.