2017 ACVIM Forum Research Abstract Program

Horses used for pleasure riding had lower performance indicators (V 200 , V 4 ) than horses used for higher level eventing competition. Fitness level did not influence the very low beat-to-beat variability seen in this population of horses. Arrhythmias detected in healthy horses during ridden exercise were infrequent and did not influence beat-to-beat HRV. This group of ridden horses had similar-beat to-beat HRV to that seen in an additional study (using a different data set) during exercise on a high-speed treadmill. Dysfunction of the hypothalamic-pituitary-adrenal axis (HPAA), manifested as relative adrenal insufficiency (RAI) or critical illness related corticosteroids insufficiency (CIRCI) has been associated with sepsis and mortality in newborn foals. HPAA dysfunction at the adrenal gland (cortisol) level is well documented in critically ill foals, but information at the hypothalamic (corticotropin releasing hormone [CRH] ) and pituitary (adrenocorticotropin [ACTH]) levels is lacking. We hypothesized that in most septic foals the HPAA will be activated at all three levels and the degree of activation will be linked to disease severity and mortality. We proposed that CRH and ACTH deficiency will occur in few critically ill foals and will be associated with disease severity and mortality.