Pseudo A-V block secondary to concealed junctional extrasystoles. Case report and review of the literature.

A 23 year old woman, convalescing from a motorcycle accident was noted to have a complex arrhythmia. Short bursts of apparent ventricular tachycardia, sudden P-R delays, and Mobitz I and Mobitz II block were observed as well as frequent junctional premature systoles. Careful analysis revealed that the rhythm disturbances were caused entirely by manifest and concealed atrioventricular (A-V) junctional extrasystoles. This case meets the criteria for concealed junctional extrasystoles producing "pseudo A-V block." Pertinent literature is reviewed, and the manifestations of variable antegrade and retrograde conduction of A-V junctional extrasystoles are discussed. Increased awareness of this unusual rhythm disturbance can prevent unnecessary pacemaker therapy for apparent A-V block.