What characterizes Wolff-Parkinson-White syndrome?

Wolff-Parkinson-White syndrome is characterized by the presence of an accessory pathway, known as the Bundle of Kent, that allows electrical impulses to bypass the normal conduction system of the heart. This extra pathway can facilitate early depolarization of the ventricles, leading to a reentrant circuit that may cause tachycardia. The accessory pathway enables the atrial impulses to reach the ventricles more quickly than through the normal AV node, contributing to the characteristic features of the syndrome.

While wide QRS complexes may be observed in Wolff-Parkinson-White syndrome during episodes of tachycardia due to the fast conduction through the accessory pathway, the hallmark of the condition is specifically the presence of that accessory conduction pathway itself. The condition does not lack accessory pathways; rather, it is defined by their existence and the resultant effects on heart rhythm and conduction. Regular ventricular rates can occur during normal sinus rhythm but may vary during episodes of tachycardia, and the syndrome is indeed characterized more prominently by the presence of those accessory pathways. Therefore, noting that an accessory pathway exists that transmits impulses is crucial for understanding the electrophysiological mechanisms involved in Wolff-Parkinson-White syndrome.