Radiofrequency ablation of atrioventricular nodal reentrant tachycardia: mechanisms and recurrence rate

Radiofrequency catheter ablation is the treatment of choice in atrioventric ular nodal reentrant tachycardia. Electrophysiologic investigations in 623 patients revealed eight mechanisms of tachycardia ablation: Ablation of fas t (I) or slow (II), modification of fast (III) or slow AV nodal pathways (I V), modification of both pathways (V), ablation of fast and modification of slow (VI), ablation of slow and modification of fast pathways (VII) and ab lation of both pathways (VIII). The criteria of diagnosis of these eight me chanisms of tachycardia ablation are described. Follow-up showed fewer rela pses in patients with ablation (0-2 %) in comparison to patients with modif ication of a single AV nodal pathway (8-12 %). Alteration of both pathways includes an increasing risk of total AV nodal block, which occured in 7 pat ients (1.1 %). Detailed analysis of the mechanism of catheter ablation is r ecommended in all patients after radiofrequency current delivery for AV nod al reentrant tachycardia to estimate the risk of relapse during follow-up o r development of total AV block in the particular patient in case of a furt her ablation procedure.