Utility of Exercise Testing and Adenosine Response for Risk Assessment in Children with Wolff-Parkinson-White Syndrome

BACKGROUND: We aimed to determine the correlation between noninvasive testing (exercise stress testing [EST] and adenosine responsiveness of accessory pathway [AP] ) and invasive electrophysiology study (EPS) for assessment antegrade conduction of the AP in Wolff-Parkinson-White syndrome. PATIENTS AND METHOD: This prospective, observational study enrolled 40 children (58% male children, median age of 13 years, and median weight of 47.5 kg) with Wolff-Parkinson-White syndrome. Conduction through the AP to a cycle length of ≤250 ms was considered rapid or high-risk; otherwise, patients were nonrapid or low-risk. RESULTS: The sudden disappearance of the delta-wave was seen in 10 cases (25%) during EST. Accessory pathway was found to be high-risk in 13 cases (13/40, 32.5%) while the accessory path was identified as low-risk in 27 cases; however, six patients (15%) had blocked AP conduction with adenosine during EPS. Low-risk classification by EST alone to identify patients with nonrapid conduction in baseline EPS had a specificity of 93% and a positive predictive value of 90% (accuracy 54%). Blocked AP conduction with adenosine as a marker of nonrapid baseline AP conduction had a specificity of 93% and a positive predictive value of 84%. Finally, AP was adenosine nonresponsive in the majority of patients (28/30, 93%) with persistent delta-waves, 40% of those who had a sudden disappearance of delta-waves had an adenosine-responsive AP (P value: .028). CONCLUSION: Abrupt loss of preexcitation during EST and blocked AP conduction with adenosine had high specificity and positive predictive value for nonrapid and low-risk antegrade conduction during baseline invasive EPS. Successful risk stratification of pediatric patients with Wolff-Parkinson-White is possible through the use of EST and the adenosine responsiveness of AP.