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Journal of veterinary internal medicine2018; 32(5); 1708-1717; doi: 10.1111/jvim.15287

Time-dependent antiarrhythmic effects of flecainide on induced atrial fibrillation in horses.

Abstract: Pharmacological treatment of atrial fibrillation (AF) in horses can be challenging because of low efficacy and adverse effects. Flecainide has been tested with variable efficacy. Objective: To test whether the efficacy of flecainide is dependent on AF duration. Methods: Nine Standardbred mares. Methods: Factorial study design. All horses were instrumented with a pacemaker and assigned to a control or an AF group. On day 0, all horses were in sinus rhythm and received 2 mg/kg flecainide IV. Atrial fibrillation subsequently was induced in the AF group by pacemaker stimulation. On days 3, 9, 27, and 55, flecainide was administered to all horses, regardless of heart rhythm. Results: All horses in AF cardioverted to sinus rhythm on days 3 and 9. On day 27, 5/6 horses cardioverted, whereas only 2/6 cardioverted on day 55. The time from the start of flecainide infusion to cardioversion (range, 3-185 min, log transformed) showed linear correlation with the cumulative duration of AF (r2  = .80, P < .0001). Flecainide induced abnormal QRS complexes in 4/6 AF horses and 1/3 controls. A positive correlation was found between heart rate before flecainide infusion and number of abnormal QRS complexes (0.14, P < .05). One horse suffered from cardiac arrest and died after flecainide infusion. Conclusions: Flecainide is effective for cardioversion of short-term induced AF, but the effect decreases with AF duration. Controlling heart rate may minimize adverse effects caused by flecainide, but the drug should be used with great caution.
© 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
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Publication Date: 2018-08-22 PubMed ID: 30133839PubMed Central: PMC6189357DOI: 10.1111/jvim.15287Google Scholar: Lookup
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  • Clinical Trial
  • Veterinary
  • Journal Article

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 paper investigates the effectiveness of the drug flecainide in treating atrial fibrillation (AF) in horses, examining how treatment efficacy changes over time. The study concludes that while flecainide is effective for the short-term treatment of induced AF, its effectiveness decreases the longer the AF persists.

Objectives and Research Design

  • The scientists wanted to understand whether the efficacy of using the drug flecainide to treat atrial fibrillation (AF), a common heart disorder observed in horses, is affected by the duration of the condition.
  • They used a factorial study on nine Standardbred mares, splitting the horses into a control group and an AF group. Starting from a healthy state (sinus rhythm), the horses were treated with a dose of flecainide. AF was then induced in the AF group by using a pacemaker, after which flecainide was administered to all horses on various days regardless of their heart rhythm condition.

Results and Observations

  • On days 3 and 9, all AF horses were successfully converted back to sinus rhythm. However, by day 27, only 5 out of the 6 AF horses converted, and by day 55, only 2 out of 6 had converted.
  • A noted observation was that the time taken from flecainide infusion to conversion back to sinus rhythm increased linearly with the cumulative duration of AF. This suggests that the longer the horse had AF, the longer it took for flecainide to treat it.
  • Four of the six horses with AF and one of the three controls exhibited abnormal QRS complexes (a term describing certain findings on an electrocardiogram) after flecainide administration. There was a positive correlation between the heart rate before flecainide treatment and the number of abnormal QRS complexes observed.
  • One horse suffered a cardiac arrest and unfortunately died after flecainide administration, showcasing the need for cautious use of the drug.

Conclusion and Recommendations

  • According to the findings of the study, flecainide appears to be effective for the treatment of short-term induced AF. However, its effectiveness lessens as the duration of AF increases.
  • The authors suggest that controlling the horse’s heart rate might help minimize the potential adverse effects caused by flecainide. They also caution that the medication should be used very carefully considering the reported cardiac event in one horse.

Cite This Article

APA
Carstensen H, Hesselkilde EZ, Fenner M, Loft-Andersen AV, Flethøj M, Kanters JK, Sattler SM, Tfelt-Hansen J, Pehrson S, Jespersen T, Buhl R. (2018). Time-dependent antiarrhythmic effects of flecainide on induced atrial fibrillation in horses. J Vet Intern Med, 32(5), 1708-1717. https://doi.org/10.1111/jvim.15287

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 32
Issue: 5
Pages: 1708-1717

Researcher Affiliations

Carstensen, Helena
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Hesselkilde, Eva Z
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Fenner, Merle
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Loft-Andersen, Ameli V
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Flethøj, Mette
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Kanters, Jørgen K
  • Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark.
Sattler, Stefan M
  • Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark.
  • Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians University Munich (LMU), Munich, Germany.
Tfelt-Hansen, Jacob
  • Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark.
  • Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark.
Pehrson, Steen
  • Department of Cardiology, The Heart Centre, Copenhagen University Hospital, København, Denmark.
Jespersen, Thomas
  • Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, København, Denmark.
Buhl, Rikke
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.

MeSH Terms

  • Animals
  • Anti-Arrhythmia Agents / therapeutic use
  • Atrial Fibrillation / drug therapy
  • Atrial Fibrillation / veterinary
  • Female
  • Flecainide / therapeutic use
  • Horse Diseases / drug therapy
  • Horses
  • Pacemaker, Artificial
  • Time Factors

Grant Funding

  • Marie Sklodowska-Curie grant agreement No 675351 / European Union Horizon 2020 research and innovation programme
  • 14-4713 / The Augustinus Foundation
  • 14-4713 / The Kustos Foundation of 1881

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Citations

This article has been cited 8 times.
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