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Journal of veterinary internal medicine2014; 29(1); 339-347; doi: 10.1111/jvim.12496

Antiarrhythmic and electrophysiologic effects of flecainide on acutely induced atrial fibrillation in healthy horses.

Abstract: Only few pharmacologic compounds have been validated for treatment of atrial fibrillation (AF) in horses. Studies investigating the utility and safety of flecainide to treat AF in horses have produced conflicting results, and the antiarrhythmic mechanisms of flecainide are not fully understood. Objective: To study the potential of flecainide to terminate acutely induced AF of short duration (≥ 15 minutes), to examine flecainide-induced changes in AF duration and AF vulnerability, and to investigate the in vivo effects of flecainide on right atrial effective refractory period, AF cycle length, and ventricular depolarization and repolarization. Methods: Nine Standardbred horses. Eight received flecainide, 3 were used as time-matched controls, 2 of which also received flecainide. Methods: Prospective study. The antiarrhythmic and electrophysiologic effects of flecainide were based on 5 parameters: ability to terminate acute pacing-induced AF (≥ 15 minutes), and drug-induced changes in atrial effective refractory period, AF duration, AF vulnerability, and ventricular depolarization and repolarization times. Parameters were assessed at baseline and after flecainide by programmed electrical stimulation methods. Results: Flecainide terminated all acutely induced AF episodes (n = 7); (AF duration, 21 ± 5 minutes) and significantly decreased the AF duration, but neither altered atrial effective refractory period nor AF vulnerability significantly. Ventricular repolarization time was prolonged between 8 and 20 minutes after initiation of flecainide infusion, but no ventricular arrhythmias were detected. Conclusions: Flecainide had clear antiarrhythmic properties in terminating acute pacing-induced AF, but showed no protective properties against immediate reinduction of AF. Flecainide caused temporary prolongation in the ventricular repolarization, which may be a proarrhythmic effect.
Copyright © 2014 by the American College of Veterinary Internal Medicine.
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Publication Date: 2014-10-18 PubMed ID: 25328012PubMed Central: PMC4858114DOI: 10.1111/jvim.12496Google Scholar: Lookup
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  • Clinical Trial
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research article investigates the effectiveness and safety of flecainide, a medication, in treating acutely induced atrial fibrillation (a heart condition) in horses.

Study Overview

  • The study was based on the need to understand the efficacy and safety of using flecainide to treat atrial fibrillation (AF) in horses. Not many pharmacological substances have been validated for this purpose and former studies have yielded uncertain results.
  • The specific objectives of the study were to gauge the potential of flecainide in terminating freshly induced AF, examine changes in AF duration and vulnerability induced by flecainide, and investigate the drug’s in vivo effects on right atrial effective refractory period, AF cycle length, and ventricular depolarization and repolarization.

Methodology

  • The methodology of the research involved a prospective study on nine Standardbred horses, of which eight were administered flecainide and three were used as time-matched controls. Two out of these three control horses also received flecainide treatment.
  • The antiarrhythmic and electrophysiologic effects of flecainide were evaluated based on five parameters: the drug’s ability to terminate acute pacing-induced AF, as well as its impact on atrial effective refractory period, AF duration, AF vulnerability, and ventricular depolarization and repolarization times.
  • Results were collected before and after flecainide treatment through programmed electrical stimulation methods.

Results

  • The results found that flecainide halted all abruptly induced AF episodes in the horses tested, and also significantly reduced the duration of AF.
  • However, the drug did not significantly alter the atrial effective refractory period or AF vulnerability. The ventricular repolarization time was observed to be extended between 8 and 20 minutes after the commencement of flecainide infusion, yet no ventricular arrhythmias were detected.

Conclusion

  • The conclusion drawn from the study was that while flecainide showed antiarrhythmic properties in halting acute pacing-induced AF, it did not adequately protect against immediate reinduction of AF.
  • Furthermore, the temporary prolongation of ventricular repolarization caused by flecainide could prove to be a proarrhythmic effect, which calls for further investigation into its safety profile.

Cite This Article

APA
Haugaard MM, Pehrson S, Carstensen H, Flethøj M, Hesselkilde EZ, Praestegaard KF, Diness JG, Grunnet M, Jespersen T, Buhl R. (2014). Antiarrhythmic and electrophysiologic effects of flecainide on acutely induced atrial fibrillation in healthy horses. J Vet Intern Med, 29(1), 339-347. https://doi.org/10.1111/jvim.12496

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 29
Issue: 1
Pages: 339-347

Researcher Affiliations

Haugaard, M M
  • Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Pehrson, S
    Carstensen, H
      Flethøj, M
        Hesselkilde, E Z
          Praestegaard, K F
            Diness, J G
              Grunnet, M
                Jespersen, T
                  Buhl, R

                    MeSH Terms

                    • Animals
                    • Anti-Arrhythmia Agents / therapeutic use
                    • Atrial Fibrillation / drug therapy
                    • Atrial Fibrillation / etiology
                    • Cardiac Pacing, Artificial
                    • Female
                    • Flecainide / therapeutic use
                    • Horse Diseases / drug therapy
                    • Horse Diseases / etiology
                    • Horses
                    • Male

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                    Citations

                    This article has been cited 14 times.
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