Two-dimensional, long-axis echocardiographic ratios for assessment of left atrial and ventricular size in dogs

• Published in: Journal of veterinary cardiology 2018-10, Vol.20 (5), p.330-342
• Main Authors: Strohm, L.E., Visser, L.C., Chapel, E.H., Drost, W.T., Bonagura, J.D.
• Format: Article
• Language: English
• Subjects: Canine; Cardiomegaly; Mitral regurgitation; Myxomatous mitral valve disease; Ultrasound
• ISSN: 1760-2734; 1875-0834
• DOI: 10.1016/j.jvc.2018.07.008

Left ventricular (LV) and left atrial (LA) enlargement affect management and outcome of dogs with cardiac disease. Short-axis, two-dimensional echocardiographic (2DE) images, indexed to the aorta (Ao), are frequently used to identify cardiomegaly. Long-axis images offer complementary views of the left heart. Eighty healthy dogs and 25 dogs with MMVD. Healthy dogs were prospectively recruited to determine reference intervals (Clinical Laboratory Standards Institute methodology) for long-axis ratios. Measurement variability and repeatability were quantified by intraclass correlation coefficient and coefficient of variation. Mean long-axis ratios from dogs with MMVD were compared with healthy dogs (unpaired t-test). In addition, the proportion of MMVD dogs exceeding the 97.5 percentile by LV/Ao and a conventional, allometric method were compared (McNemar’s test). Two-dimensional echocardiographic long-axis reference intervals were as follows: left ventricular to aortic dimension (LV/Ao) 1.8–2.5; left atrial to aortic dimension (LA/Ao) 1.8–2.4, and left atrial to left ventricular dimension (LA/LV) 0.9–1.1. Intraobserver and interobserver measurement agreement was good-to-excellent (intraclass correlation coefficients ≥0.84), and day-to-day variability was low (coefficient of variations