The Incidence of Retrograde Conduction in Children

With the increasing use of “physiological” Pacemakers in the pediatric age group, retrograde conduction in children has become of clinical importance. Pacemaker which sense atrial depolarization may sense “retrograde” P waves. The pacemaker may then act as the antegrade limb of a reciprocating tachycardia circuit. While the patient's own conduction system act the retrograde limb. We reviewed the data of 127 patients who underwent antegrade and retrograde electrophysiologic study at Taxes Children's Hospital, with regard A‐V node; the incidence of retrograde conduction in patients after surgical correction of a tetralogy of Fallot was singnificantly lower (33%). None of the patients with third degree A‐V block had retrograde conduction. The mean retrograde conduction time was 162 ms (range 70‐335 ms) at the slowest pacing rate and 257 ms (range 80‐475 ms) at the fastest pacing rate. This high incidence of retrograde conduction and the variability of conduction times must be taken into when “physiological” pacemaker are to be implanted.