Left Ventricular Volume Indexing in Athletic Brazilian Sport Horses Using Body Weight.

BACKGROUND

Left ventricular (LV) volume assessment evaluates cardiac size and remodelling in horses. Single-plane Simpson method of discs (SMOD) provides volumetric measurements requiring body size normalization.

AIMS/

OBJECTIVES

We described LV volumes using SMOD in healthy Brazilian Sport Horses (BH) and evaluated thoracic-girth-estimated body weight (BWe) versus scale-measured weight (BWs) for indexing.

METHODS

Thirty BH horses (15 males, 15 females; 4-16 years) underwent echocardiography. LV end-diastolic (LVEDV), end-systolic volumes (LVESV), and ejection fraction (EF%) were obtained using SMOD. Body weight was scale-measured and estimated via thoracic girth formula. Volumes were indexed to BWs, BWe, and a 500-kg reference.

RESULTS

Mean LVEDV was 1060 ± 154 mL (95% CI: 1003-1118), LVESV 318 ± 77 mL (95% CI: 290-347), and EF 70.0 ± 5.4%. Overall, BWe was associated with BWs (R² = 0.61; P < 0.0001) with mean bias of +33.25 kg (limits of agreement: -37.59 to +104.09 kg), mean absolute error of 39 ± 28.83 kg, and percentage error of 8.92 ± 7.27%. LVEDV/BWs averaged 2.30 ± 0.29 mL/kg and LVEDV/BWe 2.15 ± 0.26 mL/kg. Normalization to 500 kg yielded LVEDV[500] of 1151 ± 146 and 1069 ± 131 mL, and LVESV[500] of 346 ± 83 and 321 ± 70 mL (BWs; BWe). Indexed variables showed moderate to strong linear association between methods. In this sample, no sex or age differences were detected.

CONCLUSION

Body weight normalization improved interindividual comparability. While BWe offers a practical field alternative, estimation errors warrant caution in individual evaluations, making BWs preferred.