"Entrainment" Phenomenon during Reciprocating Tachycardia in the Wolff-Parkinson-White Syndrome

Abstract

In a case with the Wolff-Parkinson-White syndrome, the phenomenon "entrainment without interruption" was observed during spontaneous tachycardia. Electrophysiologic study revealed that the tachycardia was due to reentry with the antegrade limb being the AV node-His axis and the retrograde limb being the accessory pathway. This report is the second report showing "entrainment" phenomenon which is consistent with macro reentry as the mechanism of tachycardia as shown in atrial flutter.