Wide complex tachycardia due to automaticity in an accessory pathway.

Patients with the Wolff-Parkinson-White (WPW) syndrome have preexcited tachycardia as the result of atrial arrhythmias or antidromic reentry. This article describes a patient with persistent wide complex tachycardia due to abnormal automaticity in the accessory pathway. Radiofrequency catheter ablation resulted in simultaneous elimination of accessory pathway conduction and automaticity. Accessory pathway automaticity may be an infrequent cause of preexcited tachycardia in patients with the WPW syndrome.