Reference intervals and allometric scaling of echocardiographic measurements in Bengal cats

Objectives: The Bengal is a relatively new hybrid breed, reported to develop hypertrophic cardiomyopathy. The aim of this study was to determine reference intervals for echocardiographic measurements in Bengal cats. Animals: Sixty-six apparently healthy Bengal cats. Methods: The study included a retrospective review of echocardiograms from 39 Bengal cats evaluated from March 2004 to June 2012 and reported to be normal by a board-certified cardiologist. An additional 27 cats were enrolled prospectively from June 2012 to June 2013. The effects of sex and body weight on linear cardiac dimensions were evaluated by regression analysis. Reference intervals were determined by the robust method with bootstrapping. Allometric equations scaled to body weight were derived for each echocardiographic variable. Intra- and interobserver variability were evaluated by coefficient of variation from 6 of the prospective studies. Results: Reference intervals were determined from all 66 Bengal cats as no significant differences were observed between the retrospective and prospective data. An effect of sex, separate from body weight, was suggested and unique reference intervals for male and female cats were determined. Body weight was a significant co-variate and 95% prediction intervals for linear dimensions were determined by allometric scaling. Coefficients of variation were less than 10% for 2-dimensional variables and less than 18% for M-mode variables. Conclusions: These data provide reference intervals and weight-based 95% prediction intervals for echocardiographic measurements in the Bengal cat, potentially aiding cardiologists who screen this breed in detecting pathologic variants from normal dimensions. (C) 2015 Elsevier B.V. All rights reserved.