1. An aberrant conduction pathway between ventricles and atria allows impulses to be conducted in a circular pathway, without involving the SA node. The ECG shows rapid, narrow complexes without visible p-waves. 2. Paroxysmal supraventricular tachycardia (PSVT) has become nearly synonymous with its most common variant, called atrioventricular nodal reentry tachycardia (AVNRT), wherein a functional anomaly creates a reentry circuit within the AV node (see Fig. 119.1). 3. Less common is atrioventricular reciprocating tachycardia (also called AV reentrant tachycardia or AVRT), which involves an anatomically separate reentry pathway called the bundle of Kent. The most common form of AVRT is Wolff-Parkinson-White (see entry: WPW) (Fig. 119.2).