Treatment of supraventricular tachycardia in a horse.
Abstract: To describe the treatment of persistent supraventricular tachycardia (SVT) in a young horse in endurance training. Methods: A 6-year-old Arab gelding in endurance training presented for a dysrhythmia and decreased performance. SVT was diagnosed and conversion to a normal sinus rhythm was achieved following administration of a constant rate infusion of amiodarone. However, reversion to SVT occurred shortly after initiation of ridden exercise. A second attempt to convert the dysrhythmia with amiodarone failed, but normal sinus rhythm was achieved with transvenous electrical cardioversion (TVEC). Postmortem examination of the heart revealed extensive fibrous replacement of most of the left atrial myocardium; these changes likely provided the structural substrate for the dysrhythmia. The underlying cause of the fibrosis was not identified. Conclusions: SVT is a form of supraventricular tachyarrhythmia rarely diagnosed in the horse. A recent report has described sudden death of a horse following attempted conversion of SVT with oral flecainide acetate. In the present report, we describe short-term conversion of SVT in a horse using intravenous amiodarone with no significant adverse effects. When the dysrhythmia recurred, the animal was donated for teaching purposes and conversion was achieved with TVEC. Normal sinus rhythm persisted for 2 weeks until the horse was euthanized for postmortem evaluation of the heart. Intravenous amiodarone or TVEC could be considered as treatments for supraventricular tachyarrhyhmias other than atrial fibrillation in the horse.
© Veterinary Emergency and Critical Care Society 2017.
Publication Date: 2017-03-07 PubMed ID: 28267896DOI: 10.1111/vec.12591Google Scholar: Lookup
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Summary
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This research describes the unique case of treating supraventricular tachycardia (SVT), a rare heart condition, in a horse under endurance training using drug administration and electrical cardioversion.
Case Introduction and Diagnosis
- The researchers introduce us to their case, a 6-year-old Arab gelding horse, which is presenting symptoms of arrhythmia and decreased performance.
- This horse is diagnosed with supraventricular tachycardia (SVT), a condition that causes the heart to beat more rapidly than normal due to improper electrical activity in the upper part of the heart.
Treatment Approach
- The first treatment approach involved the administration of a drug named amiodarone, given as a constant rate infusion. Amiodarone is a medication often used in humans to treat irregular heartbeats, and it successfully returned the horse’s heartbeat to normal.
- However, the SVT returned shortly after the horse began exercising again, which led to a second administration of amiodarone. Unfortunately, this second attempt was unsuccessful.
Application of Transvenous Electrical Cardioversion (TVEC)
- After the failure of the second amiodarone administration, a process called transvenous electrical cardioversion (TVEC) successfully restored the horse’s normal sinus rhythm. TVEC is a procedure that sends electrical signals to the heart through veins to restore normal heart rhythm.
Postmortem Examination and Unidentified Fibrosis Cause
- After the horse was euthanized, a postmortem examination of the horse’s heart showed substantial fibrous replacement in most of the left atrial myocardium.
- This alteration in the heart structure likely created the conditions necessary for the SVT to occur. Unfortunately, the researchers could not identify the underlying cause of the fibrosis.
Summary and Treatment Suggestions
- The study ends with the conclusion that, despite SVT being a rare diagnosis in horses, the successful short-term conversion of this condition using intravenous amiodarone and TVEC shows promise.
- The researchers suggest that both amiodarone and TVEC could be options to consider in treating supraventricular tachyarrhythmias in horses.
Cite This Article
APA
Whelchel DD, Tennent-Brown BS, Coleman AE, Rapoport GS, Blas-Machado U, Maisenbacher HW, Credille BC, Giguère S.
(2017).
Treatment of supraventricular tachycardia in a horse.
J Vet Emerg Crit Care (San Antonio), 27(3), 362-368.
https://doi.org/10.1111/vec.12591 Publication
Researcher Affiliations
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, VIC 3030, Australia.
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
- Veterinary Heart Care, Virginia Beach, VA, 23462.
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
- College of Veterinary Medicine, University of Georgia, Athens, GA, 30602.
MeSH Terms
- Amiodarone / administration & dosage
- Animals
- Anti-Arrhythmia Agents / administration & dosage
- Death, Sudden
- Electric Countershock / veterinary
- Emergencies / veterinary
- Horse Diseases / diagnosis
- Horse Diseases / physiopathology
- Horse Diseases / therapy
- Horses
- Male
- Physical Conditioning, Animal
- Tachycardia, Supraventricular / diagnosis
- Tachycardia, Supraventricular / physiopathology
- Tachycardia, Supraventricular / therapy
- Tachycardia, Supraventricular / veterinary
Citations
This article has been cited 1 times.- Van Steenkiste G, Boussy T, Duytschaever M, Vernemmen I, Schauvlieghe S, Decloedt A, van Loon G. Detection of the origin of atrial tachycardia by 3D electro-anatomical mapping and treatment by radiofrequency catheter ablation in horses. J Vet Intern Med 2022 Jul;36(4):1481-1490.
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