WPW is a form of supraventricular tachycardia (fast heart rate originating above the ventricles). People with WPW have more than one electrical conduction pathway in their hearts (accessory pathways. ) These electrical impulses set up a short circuit causing the heart to beat rapidly and conduct impulses in both directions. The impulses travel through the extra pathway (short cut) as well as the normal AV-His-Purkinje system. The impulses can travel around the heart very quickly, in a circular pattern, causing the heart to beat unusually fast. This type of arrhythmia is called re-entry tachycardia.