USE OF ADENOSINE TO IDENTIFY PATIENTS AT RISK FOR RECURRENCE OF ACCESSORY PATHWAY CONDUCTION AFTER INITIALLY SUCCESSFUL RADIOFREQUENCY CATHETER ABLATION

Objectives: The use of adenosine after radiofrequency catheter ablatio n of accessory pathways was prospectively studied to determine its uti lity for identifying patients at risk for recurrence of accessory path way conduction and to guide therapy that might reduce late recurrence in this group. Background: Accessory pathway conduction recurs in 5%-1 2% of patients following initially ''successful'' radiofrequency cathe ter ablation. Adenosine may facilitate conduction over accessory pathw ays that have been modified by radiofrequency delivery, thus identifyi ng patients at risk for recurrence. Methods: Radiofrequency catheter a blation was performed in 109 patients. Prior to ablation, 12-18 mg of adenosine was administered. After ablation, when all evidence of acces sory pathway conduction remained absent for at least 30 minutes, adeno sine 12-18 mg was again administered. Results: Adenosine given prior t o radiofrequency catheter ablation did not block accessory pathway con duction in any patient. Adenosine given after elimination of accessory pathway conduction induced complete atrioventricular and ventriculoat rial block in 95 patients: 11 (11.6%) subsequently had recurrence of a ccessory pathway function. Accessory pathway conduction was unmasked b y adenosine in 12 patients (11.2%). After further deliveries of radiof requency energy, 7 of these 12 patients subsequently demonstrated aden osine induced atrioventricular and ventriculoatrial block: 1 of these 7 patients experienced recurrence of accessory pathway conduction. the remaining 5 patients demonstrated persistent accessory pathway conduc tion only with adenosine: all experienced clinical recurrence of acces sory pathway function. Conclusion: The use of adenosine after presumed successful radiofrequency catheter ablation may reveal persistent acc essory pathway conduction. Elimination of this latent accessory pathwa y conduction reduces the risk for recurrence.