Atrioventricular nodal Reentrant Tachycardia with Atrioventricular Block

Atrioventricular block (AVB) during atrioventricular nodal reentrant tachycardia (AVNRT) has been well documented 1-4], although it is not a common phenomenon. The mechanism for the initiation and resolution of AVB during AVNRT have been postulated 2,4]. However, the site of AVB and its implication on the reentrant circuit in AVNRT is not clear. We illustrate two examples of AVNRT with AVB and offer further clarification on the site and mechanism of AVB.