Journal of veterinary internal medicine2026; 40(5); aalag229; doi: 10.1093/jvimsj/aalag229

Echocardiographic characteristics and evidence of ventricular remodeling in subclinical insulin-dysregulated Warmblood horses.

Palmisano, MG
·
Underwood, C
·
Sage, J
·
Stefanovski, D
·
van Eps, A
·
Slack, J

Abstract: In humans, systemic hypertension and left ventricular (LV) hypertrophy are common sequelae of metabolic syndrome and pre-diabetes warranting investigation in horses with insulin dysregulation (ID). Objective: To compare echocardiographic variables, non-invasive blood pressure (NIBP), and adipokines between Warmblood (WB) horses with and without ID. Methods: Nineteen client-owned WB horses, 5-15 years of age, presenting for elective procedures were included. Horses had no history of metabolic disease, ID, laminitis, renal or cardiac disease. Methods: Blinded cross-sectional study. Horses were divided into 2 groups ID and non-ID based on an oral sugar test (T0 insulin ≥20 μIU/mL or T60 or T90 ≥ 30 μIU/mL). Each horse underwent the following: Physical examination, body condition score, body weight, cresty neck score, and measurement of serum leptin, total, and high molecular weight adiponectin concentrations, NIBP, lateromedial radiographs, retroperitoneal fat measurement, short axis M mode echocardiographic evaluation, and 2D speckle tracking (2DST). Results: Eight horses were categorized as ID, 11 as non-ID. Evidence of LV remodeling was identified in ID horses (P < .05) with greater measurements of LV internal diameter at end diastole (ID 11.77 cm [11.2-12.3]; non-ID 11.10 [10.54-11.85]), interventricular septum at end diastole (ID 3.10 cm [2.81-3.39]; non-ID 2.46 [2.22-2.71]) and end systole (ID 5.18 cm [4.81-5.56]; non-ID 4.29 [4.06-4.51]). 2DST measures were significantly lower in the ID group (P < 0.05). Hypertension was identified in 2 horses, 1 from each group. Conclusions: Horses with mild ID have evidence of LV remodeling supportive of hypertrophy. Cardiovascular changes might be included in the overarching definition of ID.

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Publication Date: 2026-10-11 PubMed ID: 42858359PubMed Central: PMC13653561DOI: 10.1093/jvimsj/aalag229Google Scholar: Lookup

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Overview

This study examined how insulin dysregulation (ID) in Warmblood horses affects their heart structure and function using echocardiography and blood pressure measurements.
It found that horses with ID exhibit changes consistent with left ventricular remodeling and hypertrophy, similar to what is seen in humans with metabolic syndrome.

Background and Purpose

In humans, metabolic syndrome and pre-diabetes often lead to systemic hypertension and enlargement or thickening of the heart’s left ventricle (LV hypertrophy).
Insulin dysregulation (ID) in horses is a metabolic condition that could potentially cause similar cardiovascular changes.
The study aimed to compare heart measurements, blood pressure, and specific metabolic markers (adipokines) between Warmblood horses with and without ID to investigate early cardiac effects.

Study Design and Methods

A cross-sectional observational study was conducted with 19 client-owned Warmblood horses aged 5-15 years undergoing elective procedures.
Horses with a history of metabolic, cardiac, renal disease, or laminitis were excluded to avoid confounding factors.
Insulin dysregulation status was determined by an oral sugar test: horses were classified as ID if insulin levels met or exceeded set thresholds at baseline or 60 or 90 minutes post-sugar administration.
Each horse underwent:
- Physical examination and body condition scoring
- Body weight and cresty neck scoring (indicator of fat deposition)
- Measurement of circulating adipokines—leptin, total adiponectin, and high molecular weight adiponectin (substances linked to metabolism and inflammation)
- Non-invasive blood pressure (NIBP) measurement to detect hypertension
- Lateromedial radiographs and ultrasound to assess retroperitoneal fat
- Echocardiographic assessment including M-mode and 2D speckle tracking (2DST), focusing on left ventricular structure and function

Key Findings

Out of 19 horses, 8 were classified as insulin dysregulated, and 11 as non-ID controls.
Left ventricular remodeling:
- ID horses showed significantly larger LV internal diameter at end diastole (averaging 11.77 cm vs. 11.10 cm in non-ID horses).
- The thickness of the interventricular septum was greater in ID horses both at end diastole (3.10 cm vs 2.46 cm) and end systole (5.18 cm vs 4.29 cm), indicating hypertrophy or thickening of the heart muscle walls.
2D speckle tracking echocardiography measures, which assess myocardial deformation and heart muscle function, were significantly reduced in ID horses, suggesting impaired heart muscle performance.
Hypertension was rare and identified only in one horse from each group, implying blood pressure elevation was not a prominent finding in this sample.

Interpretation and Implications

The study provides evidence that even mild insulin dysregulation in horses is associated with structural changes in heart muscle suggestive of early hypertrophy.
These cardiac changes mirror features observed in humans with metabolic syndrome, who often develop LV hypertrophy and related cardiovascular risks.
This finding suggests that ID in horses may have broader systemic impacts, including on cardiovascular health.
Cardiovascular alterations might therefore be considered an important component of the definition and clinical assessment of insulin dysregulation in horses.
Further research could explore longitudinal progression, clinical outcomes, and potential therapeutic interventions to address cardiac remodeling in insulin-dysregulated horses.

Study Limitations and Considerations

The sample size was relatively small (19 horses), which may limit the generalizability of the findings.
The cross-sectional design identifies associations but cannot establish causality or progression of cardiac changes over time.
Only non-invasive blood pressure was measured, which might not detect all cases of hypertension.
Future work could include larger cohorts, long-term follow-up, and invasive hemodynamic assessments to better characterize cardiovascular risks.

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APA

Palmisano MG, Underwood C, Sage J, Stefanovski D, van Eps A, Slack J. (2026). Echocardiographic characteristics and evidence of ventricular remodeling in subclinical insulin-dysregulated Warmblood horses. J Vet Intern Med, 40(5), aalag229. https://doi.org/10.1093/jvimsj/aalag229

Publication

Journal of veterinary internal medicine

ISSN: 1939-1676

NlmUniqueID: 8708660

Country: England

Language: English

Volume: 40

Issue: 5

PII: aalag229

Researcher Affiliations

Palmisano, Megan G

Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square, PA 19348, United States.
Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, United States.

Underwood, Claire