Introduction
Antidromic atrioventricular reentrant tachycardia (AVRT) usually
requires an accessory pathway (AP) with good conduction to serve as the
anterograde limb of the circuit[1-3]. Pathways
demonstrating intermittent or unstable conduction properties are
infrequently seen in antidromic
tachycardia[1,3,4]. When mapping a pathway,
presence of AP potential often suggests a highly effective target for
ablation. Here we report a phenomenon of widely split AP potentials due
to significantly slow conduction within an atrioventricular pathway in a
patient with antidromic AVRT.