Cardiovascular changes in horses with atrial fibrillation and high thyroid hormone concentration: a case-control study.
Abstract: Hyperthyroidism is a predisposing factor for atrial fibrillation (AF) in humans. The relationship between high thyroid hormone (TH) and AF in horses has not been evaluated. Objective: The aim of this study is to identify whether (1) high TH concentrations were present in horses with AF, (2) other cardiovascular effects were observed in horses with high TH and AF, and (3) TH status affected recurrence rate. Methods: Twenty-three horses presented with naturally occurring AF. Methods: Prospective case-control clinical study. Thyroid hormone concentration was measured in horses presenting with AF. Heart rate, electrocardiogram, blood pressure, and an echocardiogram were recorded as part of their clinical workup. Recurrence rate was determined by owner/veterinarian follow-up. Results: High TH concentration was found in 60% of horses with AF. Horses in the high TH group had a higher heart rate (P=0.001), systolic blood pressure (P=0.019), left ventricular free wall thickness (P=0.026), relative wall thickness (P=0.041) and were more likely to have periods of AF with a rapid ventricular response rate (P=0.022). All horses were successfully converted to normal sinus rhythm. The likelihood of recurrence was not different between groups. Conclusions: Elevated TH concentration can be found in horses with AF. Other cardiovascular effects of high TH concentrations in other species were also present in horses with AF and elevated TH concentrations. This study recommends measuring TH concentrations in horses presenting for AF with a history of thyroid or iodine supplementation. This study also cautions against TH or iodine supplementation in healthy performance horses.
Copyright © 2022 Elsevier B.V. All rights reserved.
Publication Date: 2022-08-20 PubMed ID: 36113206DOI: 10.1016/j.jvc.2022.08.003Google Scholar: Lookup
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- Journal Article
Summary
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The research studied whether high thyroid hormone concentration causes cardiovascular changes and recurrence in horses with atrial fibrillation. It found that 60% of horses with this condition also had elevated thyroid hormone levels and showed symptomatic cardiovascular effects.
Research Objective
The research had three objectives:
- Determine whether high thyroid hormone concentrations were present in horses with atrial fibrillation.
- Investigate whether other cardiovascular effects were observed in horses with high thyroid hormone concentrations and atrial fibrillation.
- Analyze whether thyroid hormone status impacted the recurrence rate of atrial fibrillation in horses.
Research Methods
The study followed a prospective case-control clinical study setup and encompassed twenty-three horses found with naturally occurring atrial fibrillation.
- Thyroid hormone concentrations were measured and documented.
- Other clinical work data such as heart rate, ECG report, blood pressure, and echocardiogram results of all the horses were also recorded.
- The recurrence rate was ascertained through owner/veterinarian follow-ups.
Research Results
The research found that:
- 60% of horses with atrial fibrillation had high thyroid hormone concentration.
- Horses in this category also registered higher heart rate, systolic blood pressure, left ventricular free wall thickness, and relative wall thickness.
- These horses were also seen to have more periods of atrial fibrillation with rapid ventricular response rate.
- All horses, regardless of the thyroid hormone status, were converted successfully to normal sinus rhythm without incidence of recurrence between the groups.
Research Conclusion
The study found strong evidence supporting the presence of high thyroid hormone concentration in horses suffering from atrial fibrillation. The study also found similar cardiovascular symptoms in these horses as found in other species with the same condition. Therefore, the study recommends measuring thyroid hormone concentrations in horses presenting with atrial fibrillation, especially those with a history of thyroid or iodine supplementation.
More importantly, the study cautions against the use of thyroid hormone or iodine supplementation in healthy performance horses, possibly because of the correlation found between these supplements and atrial fibrillation.
Cite This Article
APA
Ter Woort F, Stefanovski D, Reef VB.
(2022).
Cardiovascular changes in horses with atrial fibrillation and high thyroid hormone concentration: a case-control study.
J Vet Cardiol, 43, 93-100.
https://doi.org/10.1016/j.jvc.2022.08.003 Publication
Researcher Affiliations
- Equine Sports Medicine Practice, Avenue Beau Séjour 83, 1410 Waterloo, Belgium. Electronic address: fterwoort@esmp.be.
- New Bolton Center, University of Pennsylvania, 382 W Street Road, 19348 PA, Kennett Square, USA.
- New Bolton Center, University of Pennsylvania, 382 W Street Road, 19348 PA, Kennett Square, USA.
MeSH Terms
- Humans
- Horses
- Animals
- Atrial Fibrillation / veterinary
- Case-Control Studies
- Horse Diseases
- Thyroid Hormones
- Iodine
Conflict of Interest Statement
Conflict of Interest Statement The authors do not have any conflicts of interest to disclose.
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