Practices and Outcome of Artificial Cardiac Pacing in 154 Dogs

Abstract

Artificial pacing (AP) is a treatment for symptomatic bradyarrhythmias unresponsive to medical therapy. This retrospective study was designed to define the practices and outcome of AP in dogs at 7 referral institutions participating in the Companion Animal Pacemaker Registry and Repository (CANPACERS). The indications, implantation techniques, complications, long‐term outcome, and owner satisfaction were examined. One hundred fifty‐four dogs were identified as undergoing AP from January 1, 1991, to January 1, 1996. Third‐degree atrioventricular (AV) block (n = 91; 59%) and sinus node dysfunction (n = 45; 29%) were the most common indications for AP. Transvenous endocardial AP systems were implanted in 136 dogs (88%), and epicardial systems were implanted in 18 (12%). Complications associated with AP were reported in 84 dogs (55%). Major complications occurred in 51 dogs (33%), including dislodgement of the pacing lead (n = 15; 10%), generator failure (n = 10; 6%), cardiac arrest during implantation (n = 9; 6%), and infection (n = 7; 5%). Minor complications occurred in 47 dogs (31%), including seroma formation (n = 18; 12%), muscle twitch (n = 17; 11%), and inconsequential arrhythmias (n = 15; 10%). Fourteen dogs (9%) experienced both major and minor complications. Survival analysis revealed 1‐, 2‐, and 3‐year survival rates of 70, 57, and 45%, respectively. Age and presence of preexisting congestive heart failure (CHF) had a negative effect on survival (P= .001). Sixty percent of dogs with preexisting CHF died within 1 year of implantation, whereas 25% of dogs without heart failure died during the same period. Owners rated their satisfaction with the procedure as high in 80% of the dogs.