Prevalence of congenital heart disease in 76,301 mixed-breed dogs and 57,025 mixed-breed cats

Objective: Assess the prevalence of congenital heart disease (CHD) in a large population of mixed-breed dogs and cats. Animals: 76,301 mixed-breed dogs and 57,025 mixed-breed cats. Methods: Retrospective review of records and examinations based on specified diagnostic criteria. Results: Among mixed-breed dogs, the prevalence of CHD was 0.13% (51.4% female) and of innocent murmurs was 0.10% (53.0% mate). Pulmonic stenosis was the most common defect followed by patent ductus arteriosus, aortic stenosis, and ventricular septa(defect. Among mixed-breed cats, prevalence of CHD was 0.14% (55.2% male) and of innocent murmurs was 0.16% (54.4% male). When the 25 cats with dynamic left or right ventricular outflow obstruction were counted with cases of innocent murmurs, the overall prevalence was 0.2%. Ventricular septal defects were the most common feline CHD followed closely by aortic stenosis and hypertrophic obstructive cardiomyopathy. There was no overall sex predilection for CHD in mixed-breed cats or dogs, and no significant difference in CHD prevalence between cats or dogs. Among dogs, subvalvular aortic stenosis and mitral valve dysplasia had a male predisposition while patent ductus arteriosus had a female predisposition. Among cats, valvular pulmonic stenosis, subvalvular and valvular aortic stenosis, and ventricular septal defects had a male predisposition while pulmonary artery stenosis had a female predisposition. Conclusions: The prevalence of CHD in a mixed-breed dogs and cats is lower than for prior studies, perhaps due to the lack of purebreds in the study population or actual changes in disease prevalence. (C) 2015 Elsevier B.V. All rights reserved.