Anesthetic management and complications during transvenous pacemaker implantation in dogs

Introduction With the growing number of veterinary centers performing pacemaker implantation in small animals, a better understanding of anesthetic management of these procedures has become essential. Most available studies focus primarily on surgical techniques, with limited discussion of anesthetic safety, efficacy, and intraoperative complications. Materials and methods Eighteen anesthetic procedures for transvenous pacemaker implantation were retrospectively reviewed in dogs treated at a veterinary referral center in São Paulo, Brazil, between 2024 and 2025. All dogs underwent clinical and laboratory evaluation, electrocardiography and/or Holter monitoring, and echocardiography. Continuous intraoperative monitoring included heart rate, electrocardiography, respiratory rate, end-tidal CO 2 , oxygen saturation, temperature, and invasive or non-invasive arterial blood pressure. Collected data included age, breed, sex, anesthetic protocol, clinical conditions, intraoperative events, and outcomes. Continuous variables were expressed as mean ± SD or median (range) according to data distribution assessed by the Shapiro–Wilk test. Group comparisons were performed using Student's t-test or Mann–Whitney U test, and categorical variables were analyzed using chi-square or Fisher's exact test ( p 0.05). Results Sixteen dogs (8 males and 8 females) underwent 18 anesthetic procedures, including two reinterventions. The main indication for pacemaker implantation was third-degree atrioventricular block (75%). Anesthetic protocols were individualized according to patient comorbidities. The most frequent anesthetic complication was hypotension (27.7%), successfully managed with fluid therapy and vasoactive support. Electrode migration occurred in 11% of procedures and required reintervention. No perioperative deaths were recorded. Discussion and conclusion Transvenous pacemaker implantation in dogs was successfully performed under individualized anesthetic management despite heterogeneous clinical conditions and absence of a standardized protocol. Hypotension was the most common anesthetic complication but was effectively treated. The routine use of temporary external pacing provided an essential safety margin for maintaining perioperative hemodynamic stability. No perioperative deaths were recorded. These findings support the feasibility and safety of tailored anesthetic strategies for canine pacemaker implantation, although prospective studies with larger populations are warranted to define optimal standardized protocols.