The effects of activity, body weight, sex and age on echocardiographic values in English setter dogs

Background: Breed-specific reference intervals improve echocardiographic interpretation and thereby reduce misdiagnoses, especially in athletic breeds. Objectives: The objectives of the study were to examine transthoracic echocardiographic values in healthy adult English setter dogs and determine the effects of activity, body weight, sex and age on these values. Animals, materials and methods: One hundred and one adult English setter dogs, recruited from local veterinary clinics and from the Norwegian English setter club, underwent routine transthoracic echocardiography. The population was stratified into two groups based on the reported level of activity. The effects of activity level, body weight, sex and age on echocardiographic variables were examined. Results were compared with published data from other breeds and from a pre-existing species-wide allometric model. Results: Of the 100 dogs between 19 months and ten years of age included in the study, 72 were reported as very active and 28 as less active. Echocardiographic intervals were calculated for body size–independent echocardiographic variables. The upper limits of the intervals for left-atrial-to-aortic ratios and normalised left ventricular volumes exceeded those of various, previously published studies of other breeds. Normalised left ventricular dimensions exceeded published allometric 95th percentile upper reference values in 13% of dogs in diastole and 32% of dogs in systole. More active dogs had larger cardiac dimensions than less active dogs; however, the activity level did not predict echocardiographic variables when included in a multiple regression model. Conclusions: The study provides breed specific transthoracic echocardiographic values for English setter dogs, thereby contributing to improve diagnostic assessment of cardiac health in this breed.