concealed conduction concealed conduction concealed conduction is tissue stimulation without direct effect, but leading to a change in conduction characteristics. laddergram illustrating interpolated vpbs and concealed conduction a common example would be an interpolated pvc (a type of premature ventricular contraction) during normal sinus rhythm; the pvc does not cause an atrial contraction, because the retrograde impulse from the pvc does not completely penetrate the av node. however, this av node stimulation can cause a delay in subsequent av conduction by modifying the av node's subsequent conduction characteristics. hence, the p-r interval after the pvc is longer than the baseline p-r interval. another variation on this concept is seen in atrial flutter. as a result of the rapid atrial rate, some of the atrial activity fails to get through the av node in an antegrade direction but can alter the rate at which a subsequent atrial impulse is conducted. in this circumstance, an alteration in the f-wave to qrs relationship is seen.