Comparison of responses to isoproterenol and epinephrine during head-up tilt in suspected vasodepressor syncope.

pathway and subtle preexcitation, the AH intervals were short. These data pertain to a predominantly adult population. Only 1 of the patients was <12 years old. This patient showed a minimal preexcitation pattern and the pathway was in the left lateral region. These data cannot be extrapolated to the pediatric population, in general, who may have relatively shorter atrioventricular nodal conduction times, or to patients with decremental anterograde accessory pathways who may have longer accessory pathway conduction times. Nonetheless, the presence of a minimal preexcitation pattern in the adult with WPW syndrome is a useful first approximation to localizing the accessory pathway to the left lateral region.