Complication Rates Associated with Transvenous Pacemaker Implantation in Dogs with High‐Grade Atrioventricular Block Performed During versus After Normal Business Hours

BACKGROUND: Transvenous pacemaker implantation in dogs is associated with a relatively high complication rate. At our institution, pacemaker implantation in dogs with high‐grade atrioventricular block (HG‐AVB) frequently is performed as an after‐hours emergency. HYPOTHESIS: Among dogs with HG‐AVB, the rate of major complications is higher when pacemakers are implanted after hours (AH) compared to during business hours (BH). ANIMALS: Client‐owned dogs with HG‐AVB that underwent transvenous pacemaker implantation between January 2002 and December 2012 at the North Carolina State University Veterinary Teaching Hospital. METHODS: Retrospective medical record review. Two‐year follow‐up was required for complications analysis. RESULTS: Major complications occurred in 14/79 dogs (18%) and included lead dislodgement, lead or generator infection, lead or generator migration, and pacing failure. Incidence of major complications was significantly higher AH (10/36, 28%) compared to BH (4/43, 9%; P = .041), and all infectious complications occurred AH. Median survival time for all dogs was 27 months and did not differ between AH and BH groups for either all‐cause (P = .70) or cardiac (P = .40) mortality. AH dogs were younger than BH dogs (P = .010), but there were no other clinically relevant differences between BH and AH groups in terms of demographic, clinical, or procedural variables. CONCLUSIONS AND CLINICAL IMPORTANCE: At our institution, AH transvenous pacemaker placement is associated with a higher rate of major complications (especially infections) compared to BH placement. This difference may be because of a variety of human factor differences AH versus BH.