Echocardiographic assessment of left ventricular size and systolic function in Warmblood horses using linear measurements, area-based indices, and volume estimates: A retrospective database analysis.
Authors: Berthoud Djamila, Schwarzwald Colin C
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Echocardiographic Assessment of Left Ventricular Size and Function in Warmbloods Cardiac ultrasound evaluation in horses relies heavily on one-dimensional measurements, yet two- and three-dimensional indices offer potentially more accurate assessment of left ventricular (LV) size and contractility—information particularly valuable when evaluating horses with valvular disease. Researchers analysed echocardiographic data from 30 healthy Warmblood horses and 70 with mitral or aortic regurgitation, establishing reference intervals for conventional linear measurements alongside area-based and volumetric measurements, whilst testing whether adjusting variables for bodyweight improved clinical interpretation. All measurement methods demonstrated sufficiently low variability for clinical application; notably, allometric scaling effectively corrected diastolic LV dimensions and cardiac output for differences in bodyweight between individual horses. However, different echocardiographic indices frequently yielded conflicting conclusions about whether LV enlargement or systolic dysfunction was present in both healthy horses and those with valvular disease—a critical finding suggesting that relying on any single measurement risks misclassification. For practitioners assessing performance horses or those with suspected cardiac disease, evaluating multiple indices simultaneously (combining traditional M-mode with area-based and volumetric assessments, particularly those capturing long-axis motion) provides greater diagnostic confidence than conventional single-measurement approaches, though establishing a standardised protocol for clinical practice remains necessary.
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Practical Takeaways
- •When assessing LV size and function echocardiographically, do not rely on a single measurement type; use multiple indices (1D, 2D, and 3D where available) to avoid misdiagnosis of cardiac enlargement or dysfunction
- •Body weight should be considered when interpreting LV dimensions in horses of different sizes, as allometric scaling improves accuracy of assessment
- •Reference values for Warmblood horses are now available to distinguish normal cardiac adaptation from pathological enlargement in horses with valvular disease
Key Findings
- •Reference intervals established for echocardiographic indices of LV size and systolic function in healthy Warmblood horses with measurement variability sufficiently low for clinical use
- •Allometric scaling effectively corrected diastolic LV dimensions and cardiac output for differences in body weight
- •Different echocardiographic indices (1D, 2D, 3D) produced different conclusions about LV enlargement and systolic dysfunction in both healthy horses and those with valvular regurgitation
- •Joint assessment of multiple uni- and multidimensional indices including area-based or volumetric indices reflecting long-axis motion is recommended for accurate LV assessment