Abstract: Background – Insulin dysregulation (ID) is correlated with cardiac disease in humans and myocardial hypertrophy in ponies.Hypothesis/Objectives – The presence of ID will be associated with cardiac hypertrophy and hypertension in a population of Warmblood horses.Animals – Nineteen client-owned Warmblood horses 5-15 years of age were included. Horses presented to the hospital for elective procedures were considered eligible. Patients with a history of thyroid supplementation, valvular or congenital cardiac disease were excluded. Methods – The study utilized a prospective cohort design. Horses were classified as ID positive (+) or ID negative (-) based on results of an oral sugar test. Lateromedial front foot radiographs, non-invasive blood pressure (NIBP) measurements, and focused left ventricular (LV) M-mode echocardiographic assessment and measurements were performed, with calculation of mean wall thickness (MWT), relative wall thickness (RWT), LV mass (LVM) and intraventricular septal thickness in systole (IVSs) and diastole (IVSd). Data were analyzed using linear regression with statistical significance set at p< .05.Results – Eight of nineteen horses were ID(+), 2 of which had radiographic evidence of laminitis. Mean, systolic, and diastolic NIBP were not associated with ID or echocardiographic variables. ID was associated with IVSd (p=.023), MWT (p=.036), and LVM (p=.033). IVSs >4.9 mm was a perfect predictor for ID.Conclusions and clinical importance – ID was associated with cardiac hypertrophy in Warmblood horses, particularly increases in IVS thickness. Although ID was not associated with hypertension, a larger sample size is needed to examine this and any associations with laminitis.
