Paradoxical preexcitation during cryoablation of a concealed parahisian accessory pathway

A 16‐year‐old male presented with an orthodromic atrioventricular reentrant tachycardia over a concealed parahisian accessory pathway (AP). Cryoablation of the AP resulted in transient manifestation of a fully preexcited sinus rhythm of parahisian AP morphology. Potential causes for the paradoxical preexcitation include inadvertent atrioventricular nodal block, sourse‐sink mismatch, as well as the activation of a dormant AP capable of anterograde conduction.