Supraventricular tachycardia in dogs: 65 cases (1990–2007)

Objective – To characterize the signalment, clinical findings, and prognosis of dogs with supraventricular tachycardia (SVT). Design – Retrospective study. Setting – North Carolina State University Veterinary Teaching Hospital. Animals, Intervention, and Measurements – Case selection included all patients at the veterinary teaching hospital with SVT during years 1990–2007. Medical records from dogs with at least 1 recorded episode of SVT were extracted. The signalment, history, electrocardiographic, radiographic, and echocardiographic findings, therapy, and response to therapy were reviewed and summarized. Follow‐up was conducted to determine the date and cause of death. Kaplan‐Meier survival curves were constructed and analyzed. The relationships between patient characteristics and responses to therapy and prognosis were evaluated. Main Results – Sixty‐five records documented a diagnosis of SVT. Sixty‐two percent were males. Labrador Retrievers and Boxers were overrepresented compared with the general hospital population. Median age at presentation was 9 years (range 0.5–15.5 y). The median heart rate during SVT was 270/minute (range 187–375/min). The most common presenting complaint was syncope (30%), 23% were asymptomatic at the time of diagnosis. Most dogs had structural heart disease (65%). Median survival was 472 days (<1–2007 d). Identification of sustained SVT (>30 s) did not affect survival (P=0.50), nor did the presence of congestive heart failure (P=0.70). Conclusions – The majority of dogs with SVT had structural heart disease or a severe concurrent illness at the time of SVT diagnosis. SVT, though often a persistent and occasionally sustained arrhythmia, does not appear to be a primary factor in mortality.