Atrial fibrillation in horses: factors associated with response to quinidine sulfate in 77 clinical cases.
Abstract: Seventy-seven horses with atrial fibrillation (AF) were treated orally with quinidine sulfate (QS) at the University of Pennsylvania, School of Veterinary Medicine, Thirty-seven horses (48%) had adverse reactions to QS, the most common of which were nasal mucosal edema, anorexia, colic, and diarrhea. The mean highest daily QS dose was slightly greater in horses showing toxicity (P less than 0.1) and their conversion rate was less (P less than 0.05). A schedule of gradually increasing QS dose was time consuming, costly and not associated with fewer adverse reactions. Horses were compared by their response to QS: conversion for at least 12 months (Group I; 25 horses); reversion with 12 months (Group II; 8); nonconversion (Group III; 14). All horses with congestive heart failure (CHF) failed to convert. The mean age (P less than 0.05), total QS dose and highest daily QS dose (P less than 0.05) were significantly greater in Group III horses. The mean duration of signs before treatment and occurrence of adverse reactions to QS were greater in horses in Group II and III than Group I. (P less than 0.05). All horses in Groups I and II returned to performance, and many (81%) were successful. Most Group III horses (13/14) are known to have died. It was concluded that most horses with AF uncomplicated by CHF have a good prognosis when treated early with QS. Delayed QS therapy may reduce chances for conversion of AF or increase the probability of reversion.
Publication Date: 1982-10-01 PubMed ID: 6754252
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- Clinical Trial
- Comparative Study
- Journal Article
Summary
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This study investigated the effectiveness and side effects of quinidine sulfate (QS) in treating atrial fibrillation (AF) in horses, revealing the prognosis for horses with uncomplicated AF can be promising when timely treatment is given.
Study Overview
- The research was conducted at the University of Pennsylvania, School of Veterinary Medicine, where 77 horses with atrial fibrillation (AF) were treated with quinidine sulfate (QS).
- The horses were treated orally with QS and their reactions to the drug were observed and recorded.
- The treated horses were then divided into three groups based on their response to QS: those who had successful conversion for at least 12 months (Group I); those who had reversion with 12 months (Group II); and those who did not convert (Group III).
Results
- Almost half (48%) of the treated horses had adverse reactions to QS, with the most common side effects being nasal mucosal edema, anorexia, colic, and diarrhea.
- The average highest daily QS dose was slightly higher in horses showing adverse effects.
- The rate of conversion to normal heart rhythm was lower in these horses as compared to those that did not experience adverse effects.
- Among the three groups, horses in Group III (those who did not convert) were significantly older, received a greater total QS dose and highest daily QS dose. Additionally, they exhibited longer duration of signs before treatment and experienced more adverse reactions to QS.
- All horses in Groups I and II returned to performance, with a high success rate of 81%. But, most horses in Group III (13 out of 14) died.
Conclusion
- The study concludes that horses with AF that is not complicated by congestive heart failure have a good prognosis when treated early with QS.
- Delaying QS therapy may, however, reduce the chances of restoring a normal heart rhythm or increase the probability of the AF returning.
Cite This Article
APA
Morris DD, Fregin GF.
(1982).
Atrial fibrillation in horses: factors associated with response to quinidine sulfate in 77 clinical cases.
Cornell Vet, 72(4), 339-349.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Atrial Fibrillation / drug therapy
- Atrial Fibrillation / veterinary
- Clinical Trials as Topic / veterinary
- Drug Administration Schedule
- Female
- Horse Diseases / drug therapy
- Horses
- Male
- Quinidine / administration & dosage
- Quinidine / therapeutic use
Citations
This article has been cited 9 times.- Kuroda T, Minamijima Y, Kinman CK, Takahashi Y, Ebisuda Y, Inoue K, Ishikawa H, Mita H, Tamura N, Nukada T, Toutain PL, Ohta M. Rational quinidine dosage regimen for atrial fibrillation in Thoroughbred racehorses based on population pharmacokinetics. Front Vet Sci 2024;11:1454342.
- Leduc L, Abraham M, Slack J. Intravenous administration of quinidine and metoprolol for treatment of atrial fibrillation in 2 neonatal foals. J Vet Intern Med 2024 Sep-Oct;38(5):2783-2789.
- Burns JJ, MacMillan KM, John EE. Retrospective review of atrial fibrillation in Standardbred racehorses at a tertiary care facility in Atlantic Canada. Can Vet J 2022 Oct;63(10):1051-1056.
- Buhl R, Hesselkilde EM, Carstensen H, Hopster-Iversen C, van Loon G, Decloedt A, Van Steenkiste G, Marr CM, Reef VB, Schwarzwald CC, Mitchell KJ, Nostell K, Nogradi N, Nielsen SS, Carlson J, Platonov PG. Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion. Equine Vet J 2022 Nov;54(6):1013-1022.
- McGurrin MKJ. The diagnosis and management of atrial fibrillation in the horse. Vet Med (Auckl) 2015;6:83-90.
- Decloedt A, Schwarzwald CC, De Clercq D, Van Der Vekens N, Pardon B, Reef VB, van Loon G. Risk factors for recurrence of atrial fibrillation in horses after cardioversion to sinus rhythm. J Vet Intern Med 2015 May-Jun;29(3):946-53.
- Haugaard MM, Pehrson S, Carstensen H, Flethøj M, Hesselkilde EZ, Praestegaard KF, Diness JG, Grunnet M, Jespersen T, Buhl R. Antiarrhythmic and electrophysiologic effects of flecainide on acutely induced atrial fibrillation in healthy horses. J Vet Intern Med 2015 Jan;29(1):339-47.
- Reef VB, Bonagura J, Buhl R, McGurrin MK, Schwarzwald CC, van Loon G, Young LE. Recommendations for management of equine athletes with cardiovascular abnormalities. J Vet Intern Med 2014 May-Jun;28(3):749-61.
- De Clercq D, Decloedt A, Sys SU, Verheyen T, Van Der Vekens N, van Loon G. Atrial fibrillation cycle length and atrial size in horses with and without recurrence of atrial fibrillation after electrical cardioversion. J Vet Intern Med 2014 Mar-Apr;28(2):624-9.
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