Utility of adenosine 5′-triphosphate in predicting early recurrence after successful ablation of manifest accessory pathways

The purpose of this study was to determine whether administration of adenosine 5′-triphosphate (ATP; 20–40 mg) after successful ablation of accessory pathway (AP) with manifest preexcitation is useful for detecting residual conduction and predicting early recurrences. The reported incidence of recurrence of AP conduction after an initially successful procedure is 5% to 10%. Little information on the variables related to early recurrence has been reported. We prospectively used 108 ATP tests on 100 consecutive patients (66 men, mean age 36 ± 15 years) with manifest preexcitation. Five minutes after successful ablation, intravenous boluses of ATP at increasing doses were injected until the target effect of second- or third-degree AV block or AP conduction was observed. The effect of ATP was AV block (negative test) in 82 cases (76%), conduction over previously ablated AP (positive test) in 9 cases (8.3%), and no achievement of target effect (nondiagnostic test) in 17 cases (15.7%). Thirteen early recurrences were observed in 12 patients. In all 9 (100%) patients with positive ATP test and in 4 (4.9%) of the 82 patients with negative ATP test, conduction over the AP recurred (relative risk 20; 95% confidence interval 8–53; P < .000001). The diagnostic accuracy of the test (analyzing the target effect) was 95%, sensitivity 69%, specificity 100%, and positive and negative predictive values 100% and 95%, respectively. ATP administration after successful ablation of APs has a high predictive value for early recurrence and may help optimize the duration of the ablation procedure.