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Background 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). Methods 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. Results 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%. Conclusions 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. [ABSTRACT FROM AUTHOR]

Background: In Wolff-Parkinson-White (WPW) syndrome, rapid antegrade conduction of atrial tachyarrhythmias can result in ventricular fibrillation and sudden death. Antegrade conduction can be assessed through noninvasive testing or invasive electrophysiology study (EPS). We aimed to determine the correlation between noninvasive testing and EPS in a pediatric WPW population. Methods: All WPW patients <21 years who underwent EPS over a 10-year period were identified. Noninvasive testing reviewed included electrocardiogram, Holter, and exercise stress test (EST). Patients were classified as low-risk if preexcitation was lost during any test. EPS data reviewed included antegrade conduction during atrial pacing and atrial fibrillation. Conduction through the accessory pathway (AP) to a cycle length ≤250 ms was considered rapid, otherwise patients were nonrapid. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of noninvasive testing to correctly identify nonrapid conduction was calculated. Results: There were 135 EPS. Twenty-four patients (18%) were classified low-risk noninvasively. Two of the 24 (8%) had rapid conduction at baseline EPS. The sensitivity, specificity, PPV, and NPV of low-risk noninvasive testing to predict nonrapid conduction was 22%, 94%, 92%, and 31%, respectively. Sixteen of the 24 had low-risk EST and none had rapid conduction at baseline EPS. The specificity and PPV of low-risk EST were 100%. Conclusion: Loss of preexcitation during noninvasive testing had high specificity and PPV for nonrapid antegrade conduction during baseline EPS. Abrupt loss of preexcitation during EST was a highly reliable noninvasive marker of nonrapid AP conduction at baseline in our pediatric WPW patients. (PACE 2012;35:1451-1457) [ABSTRACT FROM AUTHOR]