What to know about subclinical heart murmurs in cats

Abstract

Objectives The aim of this study was to define the clinical characteristics of cats referred for evaluation of subclinical cardiac murmurs, and, secondarily, to identify predictors of echocardiographic identification of cardiac disease. Methods One hundred and sixty-three apparently healthy cats with subclinical murmurs were retrospectively enrolled. Medical records of cats older than 1 year of age referred for the evaluation of subclinical murmurs were reviewed. Cats were considered healthy if clinical signs of systemic disease or cardiac disease were not reported and cats were not receiving cardiac medications. Logistic regression was used to identify clinical variables that predict echocardiographic identification of cardiac disease. Results One hundred and eight cats (66.3%) had echocardiographic evidence of cardiac disease with hypertrophic cardiomyopathy being the most common (80.5%). Left atrial enlargement was uncommon; in 90% of cats with echocardiographically identified cardiac disease, the left atrial aortic ratio from two-dimensional echocardiography was <1.51. Cats with cardiac disease were more likely to be male ( P = 0.016), weigh more ( P <0.01) and have a murmur of intensity ⩾3/6 ( P = 0.019) than cats without cardiac disease. Murmur intensity ⩾grade 3/6 ( P = 0.01) and male sex ( P = 0.01) were independent predictors of echocardiographic evidence of cardiac disease in multivariable analysis. Conclusions and relevance The majority of cats referred for evaluation of subclinical cardiac murmurs have cardiac disease. Based on left atrial dimensions, cardiac disease is generally mild. Male sex and a loud cardiac murmur are associated with the identification of cardiac disease.