Treatment of recent-onset atrial fibrillation with quinidine and flecainide in Thoroughbred racehorses: 107 cases (1987-2014).
Abstract: OBJECTIVE To compare the efficacy of quinidine and flecainide in treating naturally occurring, recent-onset atrial fibrillation (AF) in Thoroughbred racehorses. DESIGN Retrospective case series. ANIMALS 107 Thoroughbred racehorses. PROCEDURES Medical records of racehorses with AF that were treated with quinidine or flecainide between 1987 and 2014 were reviewed. Signalment, history, treatments, complications, and outcome data were collected. Horses were allocated to 2 groups according to the initial treatment: initial treatment with quinidine (group 1) or initial treatment with flecainide (group 2). Horses in group 2 that did not convert to sinus rhythm with flecainide were then administered quinidine (group 3). Complications, total quinidine dose, and duration of treatment were compared. Rates of conversion for horses treated with quinidine versus flecainide were also compared. RESULTS Overall rate of cardioversion was 91% (97/107). There was a significant difference in the rate of cardioversion for quinidine alone (91% [71/78]), compared with flecainide alone (41% [12/29]). In group 3, the conversion rate after the addition of quinidine treatment was 82% (14/17). Total quinidine dose and treatment duration did not differ significantly between groups 1 and 3. CONCLUSIONS AND CLINICAL RELEVANCE Overall rate of cardioversion for Thoroughbred racehorses with AF was similar to that in previous reports. Flecainide treatment was less effective than quinidine treatment, but the frequency of complications did not differ between quinidine and flecainide. Further investigation is suggested to evaluate the efficacy of flecainide for cardioversion in athletic horses.
Publication Date: 2018-05-19 PubMed ID: 29772981DOI: 10.2460/javma.252.11.1409Google Scholar: Lookup
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- Journal Article
Summary
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The research focused on comparing the effectiveness of quinidine and flecainide in treating onset atrial fibrillation (AF) in racehorses. It found that quinidine was generally more effective, although rates of complications did not differ significantly between treatments.
Study Overview
- The study assessed the efficacy of quinidine and flecainide in treating recent onset of atrial fibrillation (AF), a heart condition, in Thoroughbred racehorses. AF is a condition that affects the heart’s rhythm and can lead to severe health complications if left untreated.
- The research was a retrospective case series, meaning it looked back at medical records from 1987 to 2014. The horses included had AF and were treated either with quinidine or flecainide.
Methodology
- The researchers divided the horses treated for AF into two groups based on the initial treatment they received: those treated with quinidine (group 1) and those treated with flecainide (group 2).
- If a horse in group 2 did not convert to normal sinus rhythm with flecainide, it was then given quinidine (this constitutes group 3).
- The complications, total quinidine dose, treatment duration, and conversion rates of the horses treated with either drug were compared.
Findings
- The overall rate of conversion back to normal heart rhythm (sinus rhythm) was 91% (97 out of 107 horses).
- The rate of conversion was significantly higher for horses treated initially with quinidine (91% – 71 of 78 horses) compared to those treated initially with flecainide (41% – 12 of 29 horses).
- In group 3, where horses initially treated with flecainide were administered quinidine due to failure of conversion, the conversion rate was 82% (14 of 17 horses).
- Neither the total quinidine dose nor the duration of treatment differed significantly between groups 1 and 3.
Conclusions and Clinical Relevance
- Overall, the cardioversion rate (return to normal heart rhythm) for Thoroughbred racehorses with AF was consistent with prior research.
- Flecainide treatment was less effective than quinidine, but the rate of complications was not different between either medication.
- The authors suggest further research to explore the effectiveness of flecainide in treating AF in athletic horses.
Cite This Article
APA
Takahashi Y, Ishikawa Y, Ohmura H.
(2018).
Treatment of recent-onset atrial fibrillation with quinidine and flecainide in Thoroughbred racehorses: 107 cases (1987-2014).
J Am Vet Med Assoc, 252(11), 1409-1414.
https://doi.org/10.2460/javma.252.11.1409 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Anti-Arrhythmia Agents / administration & dosage
- Anti-Arrhythmia Agents / therapeutic use
- Atrial Fibrillation / drug therapy
- Atrial Fibrillation / veterinary
- Female
- Flecainide / administration & dosage
- Flecainide / therapeutic use
- Horse Diseases / drug therapy
- Horses
- Male
- Quinidine / administration & dosage
- Quinidine / therapeutic use
- Retrospective Studies
Citations
This article has been cited 4 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.
- Vernemmen I, Van Steenkiste G, Dufourni A, Decloedt A, van Loon G. Transvenous electrical cardioversion of atrial fibrillation in horses: Horse and procedural factors correlated with success and recurrence. J Vet Intern Med 2022 Mar;36(2):758-769.
- 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.
- Carstensen H, Hesselkilde EZ, Fenner M, Loft-Andersen AV, Flethøj M, Kanters JK, Sattler SM, Tfelt-Hansen J, Pehrson S, Jespersen T, Buhl R. Time-dependent antiarrhythmic effects of flecainide on induced atrial fibrillation in horses. J Vet Intern Med 2018 Sep;32(5):1708-1717.
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