Wolff-Parkinson-White syndrome and adenosine response in pediatric patients

Adenosine administration to patients with Wolff-Parkinson-White (WPW) usually increases preexcitation and therefore may be diagnostic for WPW syndrome when the electrocardiogram (ECG) is questionable. We aimed to determine the adenosine response in pediatric patients with WPW pattern on ECG and whether blocked accessory pathway (AP) conduction with adenosine correlated with nonrapid AP conduction measured by invasive electrophysiology study (EPS).

All patients with WPW ≤ 18 years of age who underwent EPS over a 5-year period were identified. The adenosine response during atrial pacing was characterized as blocked or continued AP conduction. Invasive data were obtained during atrial pacing and atrial fibrillation. Conduction through the AP to a cycle length ≤ 250 ms was considered rapid; otherwise patients were nonrapid. The sensitivity, specificity, and positive (PPV) and negative predictive value were calculated for blocked AP conduction to identify nonrapid baseline AP conduction during EPS.

There were 59 patients included and nine (15%) had blocked AP conduction with adenosine. Five of these nine had WPW syndrome and four had fasciculoventricular APs. All nine patients had nonrapid conduction on baseline EPS. Blocked AP conduction with adenosine as a marker of nonrapid baseline AP conduction had a specificity of 100%, a PPV of 100%.

In these pediatric patients with WPW pattern on ECG, a significant minority blocked AP conduction with adenosine and this finding had 100% specificity and PPV for nonrapid baseline antegrade AP conduction. The finding of blocked AP conduction with adenosine may aid in risk stratification.