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

Abstract

BackgroundTransvenous 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.HypothesisAmong dogs with HG‐AVB, the rate of major complications is higher when pacemakers are implanted after hours (AH) compared to during business hours (BH).AnimalsClient‐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.MethodsRetrospective medical record review. Two‐year follow‐up was required for complications analysis.ResultsMajor 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 ImportanceAt 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.

Indications for permanent pacing in dogs and cats

“…As a consequence of the historically poor prognosis associated with PAS, it has been suggested that dogs with this disease are less ideal candidates for PM implantation than those affected by other bradyarrhythmias [89]. However, when considering reported data about survival times after PM implantation for other bradyarrhythmias, it appears that dogs with PAS have similar survival times [2,7,71,74,75,124,125].…”

Pacemaker lead perforation of the right ventricle associated with Moraxella phenylpyruvica infection in a dog

“…The generator site is the most common site of infection reported in dogs and people, with lead infections occurring less frequently. 1,3,5,6 In situations where the pacemaker generator site was associated with infection in dogs, in all cases it was grossly inflamed and abnormal. 6 Pre-existing myocarditis cannot be completely excluded in this case, as AV block is a recognised ECG abnormality in dogs with myocarditis.…”

“…abscess or otitis externa). 1,3,5,6 Placement of the pacemaker generator over the thoracic region rather than the cervical region may have also accounted for reduced infection rates in one canine study. 5 Prior placement of a temporary pacemaker lead and duration of procedure were not found to be associated with increased risk of infection in dogs, in contrast to findings for humans.…”

“…P acemaker perforation of the myocardium is uncommon and the estimated risk of lead perforation in dogs is 1-2%. [1][2][3] Risk factors that lead to cardiac perforation by pacemaker leads have not been clearly defined in veterinary medicine, with most being adapted from human medicine. The reported risk factors in people include systemic corticosteroid therapy prior to implantation; active fixation leads; prior temporary pacemaker lead placement; and infection of the lead.…”

“…1,2,5,6 Placement of transvenous pacemakers after hours and pacemakers that were placed by cardiologists, cardiology residents or surgeons who had performed few procedures were factors that influenced an increased risk of major complications in human patients. 3,5 Moraxella spp. are uncommon aetiological agents of cardiac infections in humans and there are no known reports of infection of this aetiology associated with pacemaker implantation in either humans or dogs.…”