Transcutaneous Auricular Vagal Nerve Stimulation in Healthy Non-Sedated Horses: A Feasibility Study.
Abstract: This study aimed to evaluate the feasibility of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses and its effect on heart rate variability (HRV). The study comprised three phases: the selection of mares, their acclimatization to the tAVNS, and the stimulation phase. Stimulation was performed with two electrodes positioned on the right pinna. The settings were 0.5 mA, 250 μs, and 25 Hz for pulse amplitude, pulse width, and pulse frequency, respectively. HRV was analysed before (B1), during (T), and after (B2) the tAVNS. From the 44 mares initially included, only 7 completed the three phases. In these mares, the heart rate (HR) was significantly lower, and frequency domain parameters showed an increased parasympathetic tone in B2 compared with B1. However, in 3/7 mares, the HR was significantly higher during T compared with B1 and B2, compatible with a decreased parasympathetic tone, while in 4/7 mares, the HR was significantly lower and the parasympathetic nervous system index was significantly higher during T and B2 compared with B1. The tAVNS is an economical and easy procedure to perform and has the potential to stimulate vagal activity; however, it was poorly tolerated in the mares included in this study.
Publication Date: 2024-05-28 PubMed ID: 38921988PubMed Central: PMC11209208DOI: 10.3390/vetsci11060241Google Scholar: Lookup
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Summary
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The research investigates the feasibility and effects of transcutaneous auricular vagal nerve stimulation (tAVNS) – a non-invasive medical procedure – on heart rate variability in healthy horses. Though results showed potential for increasing vagal activity, the procedure was generally not well-tolerated in horses involved in the study.
Objective of the Study
- The main aim of this research was to examine the practicality and impact of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses, with a specific focus on heart rate variability (HRV).
Experimental Design
- The research was conducted in three phases: selecting suitable mares for the study, accustoming the mares to tAVNS, and finally, the stage of stimulation.
- Stimulation was administered through two electrodes placed on the horse’s right ear (pinna) and was carried out under specific settings for pulse amplitude, pulse width, and pulse frequency.
- The heart rate variability (HRV) was monitored and recorded before, during, and after the stimulation phase.
Results and Findings
- Out of a total of 44 mares, only seven completed all three phases of the study.
- In these horses, a notable decrease in their heart rate and increased parasympathetic activity (a part of the nervous system that slows the heart rate) was observed in the time after stimulation when compared to measurements taken before the procedure.
- However, an inconsistent response was noted during the stimulation phase: three of the seven horses showed increased heart rates, pointing to reduced parasympathetic activity, while in the rest, lower heart rates and higher parasympathetic nervous system indexes were observed during and after stimulation as compared to the pre-stimulation stage.
- Despite these variations in responses, tAVNS demonstrated potential as a method to boost vagal activity. Nonetheless, the procedure was not well-received by the majority of the horses in this study.
Conclusion
- The research concluded that while tAVNS is a cost-effective and simple process to carry out, its tolerability among horses was somewhat lacking. Future research may require alterations or improvements to the procedure to increase its acceptance among horses.
Cite This Article
APA
Vitale V, Bindi F, Velloso Alvarez A, de la Cuesta-Torrado M, Sala G, Sgorbini M.
(2024).
Transcutaneous Auricular Vagal Nerve Stimulation in Healthy Non-Sedated Horses: A Feasibility Study.
Vet Sci, 11(6), 241.
https://doi.org/10.3390/vetsci11060241 Publication
Researcher Affiliations
- Department of Animal Medicine and Surgery, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115 Alfara del Patriarca, Spain.
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56122 Pisa, Italy.
- Department of Animal Medicine and Surgery, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115 Alfara del Patriarca, Spain.
- Department of Animal Medicine and Surgery, Institute of Biomedical Sciences, Cardenal Herrera-CEU University, CEU Universities, 46115 Alfara del Patriarca, Spain.
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56122 Pisa, Italy.
- Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56122 Pisa, Italy.
Conflict of Interest Statement
The authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.
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