Intravenous administration of quinidine and metoprolol for treatment of atrial fibrillation in 2 neonatal foals.
Abstract: Atrial fibrillation (AF) is a rarely reported arrhythmia in otherwise healthy newborn foals, with a single case of cardioversion using procainamide administration described in the literature. Two neonatal Thoroughbred colts were presented to an equine hospital because of an irregularly irregular tachyarrhythmia and poor latching when trying to nurse. History, physical examination, and initial diagnostic testing including ECG and echocardiography confirmed AF without structural heart disease. The 1st foal converted into normal sinus rhythm after treatment with IV metoprolol and quinidine. The 2nd foal converted to normal sinus rhythm after a single IV dose of metoprolol, intended for rate control. Demeanor and nursing behavior improved markedly after conversion. The 2 foals had normal heart rates and sinus rhythm that persisted for 6 weeks until euthanasia in the 1st foal and for 2 years in the 2nd foal. Rate control and cardioversion should be considered as a treatment for persistent lone AF in neonatal foals.
© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Publication Date: 2024-08-30 PubMed ID: 39212330PubMed Central: PMC11423457DOI: 10.1111/jvim.17164Google Scholar: Lookup
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Summary
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Intravenous administration of metoprolol and quinidine was used successfully to treat atrial fibrillation in two newborn foals, leading to a restoration of normal heart rhythm and improved nursing behavior.
Background and Clinical Context
- Atrial fibrillation (AF) is an uncommon heart rhythm disorder in newborn foals without underlying heart disease.
- Only one previous case of AF cardioversion in a newborn foal using procainamide has been reported before this study.
- The condition involves an irregular and rapid heart rhythm that affects the foals’ ability to nurse effectively.
Case Presentations
- Two Thoroughbred colt foals presented with:
- Irregularly irregular tachyarrhythmia detected on ECG (electrocardiogram).
- Poor nursing behavior and difficulty latching onto the mare.
- No evidence of structural heart disease on echocardiography.
Treatment Approaches Used
- Foal 1:
- Received intravenous (IV) metoprolol followed by IV quinidine administration.
- This combination successfully restored normal sinus rhythm (cardioversion).
- Foal 2:
- Received a single IV dose of metoprolol intended to control heart rate (rate control).
- This led to cardioversion to sinus rhythm, even though quinidine was not administered.
Outcomes and Follow-Up
- Both foals showed marked improvement in demeanour and nursing ability after the restoration of normal heart rhythm.
- Heart rates normalized with persistence of sinus rhythm:
- Foal 1 maintained sinus rhythm for six weeks until euthanasia due to unrelated reasons.
- Foal 2 maintained sinus rhythm for two years, demonstrating long-term efficacy.
Clinical Significance and Recommendations
- This study provides evidence that rate control and cardioversion are viable treatment options for persistent lone atrial fibrillation in neonatal foals without structural heart disease.
- Intravenous administration of metoprolol, alone or combined with quinidine, can successfully restore normal sinus rhythm in affected foals.
- These treatments can improve clinical signs such as poor nursing, which can improve survival and quality of life.
Cite This Article
APA
Leduc L, Abraham M, Slack J.
(2024).
Intravenous administration of quinidine and metoprolol for treatment of atrial fibrillation in 2 neonatal foals.
J Vet Intern Med, 38(5), 2783-2789.
https://doi.org/10.1111/jvim.17164 Publication
Researcher Affiliations
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA.
MeSH Terms
- Animals
- Horses
- Horse Diseases / drug therapy
- Animals, Newborn
- Anti-Arrhythmia Agents / therapeutic use
- Anti-Arrhythmia Agents / administration & dosage
- Quinidine / therapeutic use
- Quinidine / administration & dosage
- Atrial Fibrillation / veterinary
- Atrial Fibrillation / drug therapy
- Metoprolol / therapeutic use
- Metoprolol / administration & dosage
- Male
- Female
- Electrocardiography / veterinary
- Administration, Intravenous / veterinary
Conflict of Interest Statement
Authors declare no conflict of interest.
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This article includes 17 references
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Citations
This article has been cited 1 times.- Xu W, Li J, Ju J, Liu M, Wang W, Cheng M, Zhang X, Cui X, Chen H. The beta1-adrenergic receptor in the heart. Cell Death Discov 2025 Dec 10;12(1):46.
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