Use of intravenous flecainide in horses with naturally-occurring atrial fibrillation.
Abstract: It has been reported that i.v. flecainide has a high efficacy for the treatment of experimentally-induced acute atrial fibrillation (AF) in horses and that its use is associated with minimal toxic side effects. Objective: The objectives were to study the efficacy of i.v. flecainide as a treatment for atrial fibrillation in horses with naturally-occurring AF. Methods: Ten horses with naturally-occurring AF were treated with 2 mg/kg bwt flecainide i.v. at a rate of 0.2 mg/kg bwt/min. In 3 horses, the infusion was continued at 0.05-0.10 mg/kg bwt/min until a total dose of 3.0 mg/kg bwt had been administered. Heart rate, QRS duration and average interval between fibrillation waves were measured before, during and following flecainide infusion. If conversion to normal sinus rhythm was not achieved, horses were treated with quinidine sulphate per os at a dose of 22 mg/kg bwt given every 2 h. Results: None of the horses with chronic AF (n = 9) converted to sinus rhythm with flecainide i.v. The only horse treated successfully had acute AF of 12 days' duration. The QRS duration and fibrillation cycle length increased significantly (P = 0.006 and 0.002, respectively) during and following flecainide infusion. Heart rate did not increase significantly over time however, 3 horses developed heart rates in excess of 100 beats/min. Two horses developed a potentially dangerous ventricular dysrhythmia during the first 15 mins of treatment. Quinidine sulphate given per os restored sinus rhythm in 8 out of 9 horses, with minimal adverse effects. Conclusions: Although flecainide might be efficacious in cases of acute AF, it was not possible to restore sinus rhythm in horses with naturally-occurring chronic AF at the dosages used in this study. In 2 horses, 2.0 mg/kg bwt flecainide was associated with potentially dangerous dysrhythmias. Conclusions: Intravenous administration of 2 mg/kg bwt flecainide is unlikely to convert chronic AF in horses and could induce dangerous dysrhythmias.
Publication Date: 2004-12-08 PubMed ID: 15581326DOI: 10.2746/0425164044864516Google Scholar: Lookup
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- Journal Article
- Adverse Effects
- Atrial Function
- Cardiac Arrhythmias
- Clinical Pathology
- Clinical Study
- Clinical Symptoms
- Diagnosis
- Disease Diagnosis
- Disease Treatment
- Equine Health
- Heart
- Heart Rate
- Horses
- Intravenous Administration
- Medication
- Pharmacodynamics
- Pharmacology
- Quinidine
- Veterinary Medicine
- Veterinary Procedure
- Veterinary Research
Summary
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The research article discusses a trial to evaluate the effectiveness of intravenous flecainide treatment on horses with naturally-occurring atrial fibrillation (AF). The study revealed that for most cases, particularly chronic AF, the drug showed limited effectiveness and some cases even resulted in dangerous dysrhythmias.
Methodology
- Ten horses with naturally-occurring AF were selected for the study. They were treated with intravenous (i.v.) flecainide at a rate of 0.2 mg/kg bodyweight (bwt)/min up to a total dosage of 2 mg/kg bwt.
- In three of the horses, the i.v. flecainide infusion was continued at a slower rate (0.05-0.10 mg/kg bwt/min) until a total dose of 3.0 mg/kg bwt had been administered.
- Heart rate, QRS duration (a measure of ventricular depolarization and repolarization) and average interval between fibrillation waves were measured before, during, and after the flecainide treatment.
- If the treatment did not successfully restore normal sinus rhythm, the horses were given oral doses of quinidine sulphate (22 mg/kg bwt every 2 hours).
Results
- The treatment was unsuccessful in converting the rhythm of horses with chronic AF (9 out of the 10 horses). Only one horse, which had acute AF of 12 days’ duration, successfully converted to normal sinus rhythm.
- The QRS duration and fibrillation cycle length significantly increased during and after the flecainide infusion.
- The heart rate overall did not significantly change, though 3 horses developed heart rates in excess of 100 beats/min.
- Two horses developed potentially dangerous ventricular dysrhythmias within the first 15 minutes of the treatment.
- Oral quinidine sulphate was able to restore sinus rhythm in 8 out of the 9 horses that did not respond to the i.v. flecainide treatment, and it had minimal side effects.
Conclusions
- The study concluded that while flecainide could potentially be successful in treating acute AF, it was not capable of restoring sinus rhythm in horses with chronic, naturally-occurring AF at the dosages used in this study.
- Additionally, 2.0 mg/kg bwt flecainide resulted in potentially dangerous dysrhythmias in two of the horses, indicating its potential risks.
This reveals intravenous flecainide treatment may not be the most suitable approach in treating chronic AF in horses. Rather, oral quinidine sulphate may be a more viable option. Further study could provide deeper insight into appropriate dosage and safety measures while using flecainide, or highlight more effective alternatives.
Cite This Article
APA
van Loon G, Blissitt KJ, Keen JA, Young LE.
(2004).
Use of intravenous flecainide in horses with naturally-occurring atrial fibrillation.
Equine Vet J, 36(7), 609-614.
https://doi.org/10.2746/0425164044864516 Publication
Researcher Affiliations
- Department of Large Animal Internal Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
MeSH Terms
- Acute Disease
- Animals
- Anti-Arrhythmia Agents / adverse effects
- Anti-Arrhythmia Agents / therapeutic use
- Arrhythmias, Cardiac / chemically induced
- Arrhythmias, Cardiac / veterinary
- Atrial Fibrillation / drug therapy
- Atrial Fibrillation / veterinary
- Chronic Disease
- Female
- Flecainide / adverse effects
- Flecainide / therapeutic use
- Heart Conduction System / drug effects
- Heart Rate / drug effects
- Horse Diseases / chemically induced
- Horse Diseases / drug therapy
- Horses
- Infusions, Intravenous / veterinary
- Injections, Intravenous / veterinary
- Male
- Safety
- Treatment Outcome
Citations
This article has been cited 11 times.- 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.
- McGurrin MKJ. The diagnosis and management of atrial fibrillation in the horse. Vet Med (Auckl) 2015;6:83-90.
- Li M, Chadda KR, Matthews GDK, Marr CM, Huang CL, Jeevaratnam K. Cardiac electrophysiological adaptations in the equine athlete-Restitution analysis of electrocardiographic features. PLoS One 2018;13(3):e0194008.
- Decloedt A, Broux B, De Clercq D, Deprez P, Van Steenkiste G, Vera L, Ven S, van Loon G. Effect of sotalol on heart rate, QT interval, and atrial fibrillation cycle length in horses with atrial fibrillation. J Vet Intern Med 2018 Mar;32(2):815-821.
- Hesselkilde EZ, Carstensen H, Haugaard MM, Carlson J, Pehrson S, Jespersen T, Buhl R, Platonov PG. Effect of flecainide on atrial fibrillatory rate in a large animal model with induced atrial fibrillation. BMC Cardiovasc Disord 2017 Dec 8;17(1):289.
- 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.
- Birettoni F, Porciello F, Rishniw M, della Rocca G, Di Salvo A, Sgorbini M. Treatment of chronic atrial fibrillation in the horse with flecainide: personal observation. Vet Res Commun 2007 Aug;31 Suppl 1:273-5.
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