What is the attributing electrocardiographic phenomenon underlying a concomitant 2:1 and Wenckebach atrio-ventricular block?

Abstract

We herein describe the case of a spontaneously observed bidirectional block (both entrance and exit block) at the sino-atrial junction. This bidirectional block at the sino-atrial junction associated with the failure of conduction to the ventricle revealed the Wenckebach periodicity of the atrio-ventricular conduction.

Keywords: Atrio-sinus block; Atrioventricular block; Right bundle branch block; Sinoatrial-node; Sinus impulse.