Arrhythmogenic right ventricular cardiomyopathy in Bulldogs: Evaluation of clinical and histopathologic features, progression, and outcome in 71 dogs (2004-2016).

Objectives: This study aimed to characterize the clinical and histopathological features of arrhythmogenic right ventricular cardiomyopathy (ARVC) in English Bulldogs, American Bulldogs, and Bulldog-type mixed breed dogs and assess affected Bulldogs for a striatin gene mutation previously reported in Boxers with ARVC.

Animals: Seventy-one Bulldogs fit the inclusion criteria. Genetic analysis was performed on five dogs. Cardiac post-mortem evaluations were performed on two dogs.

Methods: Medical records from a single veterinary cardiology group (CVCA) were retrospectively evaluated. Tissue and blood samples were submitted for histopathological analysis and genetic testing in select patients.

Results: Presenting complaints included syncope (38%), arrhythmia (81.7%), or murmur (34.2%) documented on examination. On presentation, congestive heart failure (CHF) was diagnosed in 22 (31%) dogs, and 58 (81.7%) had ventricular arrhythmias. On bivariable analyses, the two-dimensional (2D) left atrial-to-aortic root ratio (LA:Ao) was the only prognostic variable significantly associated with survival time. Dogs with 2D LA:Ao below the mean (1.41) had longer median survival to all-cause mortality (12 months; 95% confidence interval [CI] six-15 months) than those with 2D LA:Ao above the mean (four months; 95% CI two-six months; p=0.0384). Most dogs (54%) died from cardiac disease, with 42.1% experiencing sudden death. The median time from diagnosis to cardiac death was four months.

Conclusions: Arrhythmogenic right ventricular cardiomyopathy affects Bulldogs with both arrhythmogenic and dilated-type phenotypes. Despite variable arrhythmia severity and predominantly right-sided involvement in many dogs, an increase in left atrial size was the only significant predictor of mortality in this sample of dogs.