Retrograde (ventriculoatrial) conduction.

Interest in retrograde VA conduction has been renewed with the advent of tachycardias induced by physiologic pacemakers with atrial sensing capabilities. Accurate representation of ventriculoatrial conduction requires detailed electrophysiologic analysis during sinus rhythm, during tachycardias whether or not associated with accessory pathways, and during ventricular pacing studies. Retrograde conduction should be assessed in patients considered for implantation of atrial sensing and tracking pacemakers (VAT, VDD, DDD), until technologic advances overcome the problems of endless loop tachycardias.