Apparent AV junctional escape in Wenckebach AV block: markedly slow conduction through the slow AV pathway.

We report here two cases of Wenckebach atrioventricular (AV) block in which apparent AV junctional escape was observed, but most likely resulted from markedly slow conduction through the slow pathway of dual AV junctional pathways. In these cases, it seems that a blocked P-wave was followed by an AV junctional escape beat. However, a blocked P-wave occasionally failed to be followed by an escape beat, and the RR interval containing the blocked P-wave was markedly longer than the above escape interval. In one case, apparent AV junctional escape beats with aberrant ventricular conduction were found, and QRS complexes of the same configuration were also found without the preceding ventricular pause. This strengthens the possibility that apparent AV junctional escape occurred because of markedly slow conduction through the slow AV pathway.