Heart rate variability in horses with naturally occurring gastric ulcers: Response to omeprazole and sucralfate treatment.

Overview

• This study investigated the heart rate variability (HRV) in horses suffering from equine gastric ulcer syndrome (EGUS), specifically focusing on whether treatment with omeprazole and sucralfate affected HRV parameters.
• The goal was to determine if HRV could serve as a non-invasive indicator of autonomic nervous system changes related to gastric ulcers and their treatment in horses.

Background

• Equine gastric ulcer syndrome (EGUS) is a prevalent condition affecting the stomachs of horses, involving ulcerations mostly in the squamous and glandular regions of the stomach.
• Heart rate variability (HRV) measures the variation in time intervals between heartbeats, providing insight into the autonomic nervous system regulation of the heart.
• HRV can reflect nervous system responses to pain and disease without invasive testing, making it a useful diagnostic tool.

Study Design and Methods

• Researchers started with a cohort of 45 mares who underwent gastroscopy to assess their gastric health at baseline (T0).
• 24 of those mares were diagnosed with Equine Squamous Gastric Disease (ESGD) scoring 2 out of 4 or greater, indicating moderate to severe ulcers; these horses were then split into two groups:
• Treated group (T): 12 mares received omeprazole and sucralfate for 28 days.
• Non-treated group (NT): 12 mares received no treatment.
• Heart rate data were collected via HR monitors before treatment (T0) and after treatment completion (T29).
• The R-R intervals from heartbeats were analyzed using commercial software to compute HRV parameters in three domains:
• Time-domain indices (which look at intervals between beats over time)
• Frequency-domain indices (which analyze variations in different frequency bands)
• Geometric indices (which assess the overall shape/pattern of RR intervals)
• Follow-up gastroscopies were performed at T29 for both groups and at T14 for the non-treated group to measure ulcer scores.

Findings

• At baseline (T0), all horses had ESGD with at least moderate severity (score 2/4 or higher).
• Equine Glandular Gastric Disease (EGGD), which affects a different stomach region, was also present in many horses but with varying severity:
• In the non-treated group: 8 out of 12 horses had EGGD with at least a score of 1/4.
• In the treated group: All 12 horses had EGGD with at least a score of 1/4.
• No significant changes in HRV parameters were found over time within either group or when comparing the two groups, suggesting HRV did not reflect changes due to treatment or ulcer presence in this study.
• The treatment was effective at significantly reducing ESGD lesion scores in the treated group (p = 0.018), showing clinical benefit of omeprazole and sucralfate for ESGD.
• However, the treatment did not significantly affect the EGGD lesion scores (p = 0.573), indicating the glandular region ulcers were less responsive to this treatment.

Conclusions and Implications

• Although therapeutic intervention improved clinical ulcer scores in the squamous region, this was not reflected in changes in HRV measures.
• The lack of HRV variation may indicate that HRV is not sensitive enough to detect autonomic system changes caused by gastric ulcers or their treatment in horses, at least under the conditions and parameters studied.
• Nonetheless, HRV remains a potentially valuable non-invasive tool for assessing autonomic nervous function related to equine gastric diseases and warrants further research.
• Future studies could explore different HRV metrics, longer treatment durations, larger sample sizes, or focus on different ulcer types and their systemic effects to clarify HRV’s clinical utility.