Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation.
Abstract: Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses. Objective: To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF. Methods: Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by 1.1 mg/kg bwt/h for 47 h. In the second phase, horses received a second loading dose of 3.74 mg AD/kg bwt/h for 1 h followed by 1.31 mg/kg bwt/h for 47 h. Clinical signs were monitored, a surface ECG and an intra-atrial electrogram were recorded. AD treatment was discontinued when conversion or any side effects were observed. Results: Three of the 6 horses cardioverted successfully without side effects. The other 3 horses did not convert and showed adverse effects, including diarrhoea. In the latter, there were no important circulatory problems, but the diarrhoea continued for 10-14 days. The third horse had to be subjected to euthanasia because a concomitant Salmonella infection worsened the clinical signs. Conclusions: The applied treatment protocol based upon pharmacokinetic data achieved clinically relevant concentrations of AD and desethylamiodarone. Conclusions: Intravenous AD has the potential to be an alternative pharmacological treatment for AF in horses, although AD may lead to adverse drug effects, particularly with cumulative dosing.
Publication Date: 2007-08-29 PubMed ID: 17722727DOI: 10.2746/042516407x182811Google Scholar: Lookup
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- Journal Article
Summary
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This research article investigates the effectiveness of a specific treatment protocol using intravenous amiodarone on horses suffering from chronic atrial fibrillation. The treatment follows two phases and achieves clinically significant concentrations, leading to successful cardioversion in half of the test subjects. However, adverse effects were also observed.
Objective and Methods Used
- The aim of the study was to evaluate an intravenous amiodarone (AD) treatment protocol, derived from human pharmacokinetic practices, for horses dealing with chronic atrial fibrillation (AF).
- For this, the researchers applied a specified AD infusion protocol on six test horses, including a loading dose, followed by maintenance.
- The protocol split into two phases: In the first round, horses received an infusion of 6.52 mg AD/kg body weight/h for 1 hour, and then 1.1 mg/kg body weight/h for 47 hours. The second phase repeated this, but with adjusted doses.
- During the treatment, horses’ clinical signs were closely observed, and an electrocardiogram recorded.
Key Findings
- The results revealed that three out of six horses showed successful cardioversion without visible side effects – indicating a 50% success rate.
- However, the remaining three horses did not show the desired conversion and experienced side effects. Notably, diarrhea remained persistent for a period of ten to fourteen days.
- In one extreme case, caused by an additional salmonella infection, the horse had to be euthanized due to deterioration in health conditions.
- Despite these side-effects, the treatment protocol resulted in relevant concentrations of AD, hence showing potential for effective use.
Concluding Insights
- The authors conclude that this treatment protocol for intravenous amiodarone appears promising as an alternative pharmacological treatment for horses suffering from atrial fibrillation.
- However, the potential for significant adverse effects, particularly with accumulated dosing, notably diarrhea, warrants further refinement before this treatment can be widely adopted.
Cite This Article
APA
De Clercq D, van Loon G, Baert K, Tavernier R, Croubels S, De Backer P, Deprez P.
(2007).
Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation.
Equine Vet J, 39(4), 344-349.
https://doi.org/10.2746/042516407x182811 Publication
Researcher Affiliations
- Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
MeSH Terms
- Amiodarone / administration & dosage
- Amiodarone / adverse effects
- Amiodarone / pharmacokinetics
- Animals
- Anti-Arrhythmia Agents / administration & dosage
- Anti-Arrhythmia Agents / adverse effects
- Anti-Arrhythmia Agents / pharmacokinetics
- Atrial Fibrillation / drug therapy
- Atrial Fibrillation / veterinary
- Diarrhea / chemically induced
- Diarrhea / veterinary
- Dose-Response Relationship, Drug
- Echocardiography / veterinary
- Echocardiography, Doppler, Color / veterinary
- Horse Diseases / drug therapy
- Horses
- Infusions, Intravenous / veterinary
- Treatment Outcome
Citations
This article has been cited 6 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.
- Costello J, Firshman AM, Brown JC, Maher M, Tadros EM. Response to thyrotropin-releasing hormone (TRH) in a horse with hyperthyroidism associated with a functional thyroid adenoma. Can Vet J 2019 Nov;60(11):1189-1193.
- 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.
- 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.
- 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.
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