The Effect of Hydration Status on the Echocardiographic Measurements of Normal Cats
Article first published online: 28 JUN 2008
© 2007 American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 21, Issue 5, pages 1008–1015, September 2007
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How to Cite
Campbell, F.E. and Kittleson, M.D. (2007), The Effect of Hydration Status on the Echocardiographic Measurements of Normal Cats. Journal of Veterinary Internal Medicine, 21: 1008–1015. doi: 10.1111/j.1939-1676.2007.tb03057.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Revised March 7, 2007; Accepted April 12, 2007
- Fluid administration;
- Heart murmur;
- Volume depletion
Background: Diagnosis of cardiomyopathy of cats is based on 2-dimensional (2D) echocardiography. However, circulating fluid volume largely determines diastolic cardiac chamber dimensions, and reduced diastolic volume in other species results in what has been called “pseudohypertrophy of the ventricular myocardium.”
Hypothesis: Altered hydration produces changes on 2D echocardiography that may confound the diagnosis or severity assessment of cardiomyopathy of cats.
Animals: Ten normal colony-sourced mixed breed cats were included.
Methods: Cats were examined by echocardiography at baseline and at completion of 3 protocols (volume depletion and maintenance-rate and anesthetic-rate IV fluid administration) applied in randomized crossover design with a 6–7 day washout period.
Results: Volume depletion increased diastolic left ventricular interventricular septal (IVSd) and free wall diameter (4.5 ± 0.4 to 5.8 ± 0.6 mm; P < .001) with wall thickness exceeding 6 mm in 4 cats. Diastolic left ventricular internal diameter (LVIDd) decreased, and reduction in systolic left ventricular internal diameter (LVIDs) produced end-systolic cavity obliteration in 7 cats. Left-atrial-to-aortic-root ratio (LA: Ao, 1.4 ± 0.2 to 1.2 ± 0.1, P < .05) and left atrial area in diastole (LAAd) decreased with volume depletion. Maintenance-rate IV fluid administration increased LAAd and fractional shortening (FS%). Anesthetic-rate IV fluid administration increased LVIDd, FS%, LAAd, and LA: Ao ratios (to 1.7 ± 0.1, P < .01), producing an LA: Ao ratio above normal limits in 6 cats. A systolic heart murmur developed with administration of fluid at maintenance (n = 1) and anesthetic rates (n = 6).
Conclusions: Altered hydration status produces changes in the echocardiographic examination of normal cats that may lead to an erroneous diagnosis of cardiomyopathy or mask its presence. Hydration status should be considered during echocardiographic examination in cats.