Adenosine-sensitive Wolff-Parkinson-White: Longer time across the atrioventricular groove.

Background: Successful ablation sites in Wolff-Parkinson-White syndrome (WPW) are characterized by short atrioventricular (AV) intervals. Approximately 15% of patients with WPW have adenosine-sensitive accessory pathways (APs). We sought to determine if local AV intervals of adenosine-sensitive APs are different from those of adenosine-insensitive APs in patients with WPW.

Methods: Patients ≤21 years with WPW and adenosine-sensitive APs who underwent successful ablation over a 9-year period were included. Patients with WPW and adenosine-insensitive APs were matched by age and weight in a 1:2 case-control design. AP location, antegrade and retrograde conduction properties, supraventricular tachycardia (SVT) inducibility, local AV interval, interval from delta wave onset to local ventricular activation (del-V), and time to loss of preexcitation were reviewed.

Results: Fourteen patients with adenosine-sensitive APs and 28 with adenosine-insensitive APs were included. Patients with adenosine-sensitive APs had minimum 1:1 antegrade AP conduction at a longer median paced cycle length (380, interquartile range [IQR] 295 to 585 ms vs 290, IQR 250 to 330 ms, P = 0.046), were less likely to have inducible SVT (35.7% vs 75.0%, P = 0.035), and had a longer median local AV interval (40.5, IQR 30.8 to 58.3 ms vs 32.0, IQR 29.3 to 37.8 ms, P = 0.029) when compared to those with adenosine-insensitive APs.

Conclusion: Patients with WPW and adenosine-sensitive APs have 1:1 antegrade AP conduction at longer cycle lengths, lower likelihood of SVT induction, and longer local AV intervals when compared to those with adenosine-insensitive APs. In patients with WPW, it may be important to consider adenosine response when selecting appropriate ablation targets.