VDD pacing in dogs: When, why and how to perform single-lead atrial synchronous, ventricular inhibited (VDD) pacing

Symptomatic, high-grade atrioventricular (AV) block remains one of the most common indications for artificial pacemaker implantation in dogs. The ideal artificial pacemaker would use the His-Purkinje system, maintain rate-responsiveness (RR), and preserve AV synchrony. Although we do not have commercially available pacing systems that accomplish all of these goals, recent advances in the development of single-lead physiologic pacemaker systems now enable maintenance of RR and AV synchrony in dogs with high grade atrioventricular block. This report outlines the indications for implantation of a single-lead atrial synchronous, ventricular inhibited (VDD) pacemaker system. The technique used for lead placement and the initial pacemaker programming required are detailed.