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Equine veterinary journal2022; 54(6); 1013-1022; doi: 10.1111/evj.13551

Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion.

Abstract: The recurrence rate of atrial fibrillation (AF) in horses after cardioversion to sinus rhythm (SR) is relatively high. Atrial fibrillatory rate (AFR) derived from surface ECG is considered a biomarker for electrical remodelling and could potentially be used for the prediction of successful AF cardioversion and AF recurrence. Objective: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses. Methods: Retrospective multicentre study. Methods: Electrocardiograms (ECG) from horses with persistent AF admitted for cardioversion with either medical treatment (quinidine) or transvenous electrical cardioversion (TVEC) were included. Bipolar surface ECG recordings were analysed by spatiotemporal cancellation of QRST complexes and calculation of AFR from the remaining atrial signal. Kaplan-Meier survival curve and Cox regression analyses were performed to assess the relationship between AFR and the risk of AF recurrence. Results: Of the 195 horses included, 74 received quinidine treatment and 121 were treated with TVEC. Ten horses did not cardiovert to SR after quinidine treatment and AFR was higher in these, compared with the horses that successfully cardioverted to SR (median [interquartile range]), (383 [367-422] vs 351 [332-389] fibrillations per minute (fpm), P < .01). Within the first 180 days following AF cardioversion, 12% of the quinidine and 34% of TVEC horses had AF recurrence. For the horses successfully cardioverted with TVEC, AFR above 380 fpm was significantly associated with AF recurrence (hazard ratio = 2.4, 95% confidence interval 1.2-4.8, P = .01). Conclusions: The treatment groups were different and not randomly allocated, therefore the two treatments cannot be compared. Medical records and the follow-up strategy varied between the centres. Conclusions: High AFR is associated with failure of quinidine cardioversion and AF recurrence after successful TVEC. As a noninvasive marker that can be retrieved from surface ECG, AFR can be clinically useful in predicting the probability of responding to quinidine treatment as well as maintaining SR after electrical cardioversion.
© 2021 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2022-01-13 PubMed ID: 34957586PubMed Central: PMC9787611DOI: 10.1111/evj.13551Google Scholar: Lookup
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  • Journal Article
  • Multicenter Study

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.

The research investigates the use of Atrial Fibrillatory Rate (AFR) to predict the possibility of Atrial Fibrillation (AF) recurring in horses that have undergone either medical treatment or transvenous electrical cardioversion therapy. It concludes that high AFR is linked to the failure of the medical treatment using quinidine and the recurrence of AF post-cardioversion.

Research Objective and Methodology

  • The goal of the study was to evaluate whether the Atrial Fibrillatory Rate (AFR), which can be collected non-invasively through electrocardiograms (ECGs), could indicate the likelihood of successfully treating Atrial Fibrillation (AF) and predict its recurrence.
  • The research conducted was a retrospective multicentre study, which included horses with persistent AF that underwent cardioversion either through medical treatment (using the drug quinidine) or transvenous electrical cardioversion (TVEC).
  • The researchers analyzed bipolar surface ECG recordings by the process of spatiotemporal cancellation of QRST complexes and calculated the AFR from the remaining atrial signal. Statistical methods including Kaplan-Meier survival curve and Cox regression analyses were used to assess the relationship between AFR and the risk of AF recurrence.

Research Outcome

  • The study included 195 horses, where 74 received quinidine treatment and 121 were treated with TVEC. Ten horses failed to cardiovert to Sinus Rhythm (SR) after quinidine treatment and they had a higher AFR compared to those that successfully converted to SR.
  • Within the first six months post-cardioversion, 12% of the horses treated with quinidine and 34% of those treated with TVEC saw recurrence of AF. For those successfully treated with TVEC, an AFR above 380 fibrillations per minute was significantly associated with AF recurrence.

Research Limitations

  • The groups under consideration for treatment weren’t randomly allocated, which makes it inappropriate to conduct a comparison between the two treatments.
  • The medical records and follow-up strategy differed between the centres involved in the study.

Conclusion

  • The study concludes that a high AFR is associated with the unsuccessful treatment of AF with quinidine and the recurrence of AF after successful TVEC treatment.
  • As AFR can be obtained non-invasively from surface ECG, it proves to be a clinically useful marker in predicting the probability of responding to quinidine treatment as well as the possibility of maintaining SR after electrical cardioversion.

Cite This Article

APA
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. (2022). Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion. Equine Vet J, 54(6), 1013-1022. https://doi.org/10.1111/evj.13551

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 54
Issue: 6
Pages: 1013-1022

Researcher Affiliations

Buhl, Rikke
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Hesselkilde, Eva M
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Carstensen, Helena
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Hopster-Iversen, Charlotte
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
van Loon, Gunther
  • Equine Cardioteam, Department of Large Animal Internal Medicine, Ghent University, Merelbeke, Belgium.
Decloedt, Annelies
  • Equine Cardioteam, Department of Large Animal Internal Medicine, Ghent University, Merelbeke, Belgium.
Van Steenkiste, Glenn
  • Equine Cardioteam, Department of Large Animal Internal Medicine, Ghent University, Merelbeke, Belgium.
Marr, Celia M
  • Rossdales Equine Hospital, Newmarket, UK.
Reef, Virginia B
  • Department of Clinical Studies New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania, USA.
Schwarzwald, Colin C
  • Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Mitchell, Katharyn J
  • Equine Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Nostell, Katarina
  • Department of Clinical Sciences, Faculty of Veteirnary Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Nogradi, Nora
  • Dubai Equine Hospital, Dubai, UAE.
Nielsen, Søren S
  • Department of Veterinary Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Carlson, Jonas
  • Department of Cardiology, Lund University, Lund, Sweden.
Platonov, Pyotr G
  • Department of Cardiology, Lund University, Lund, Sweden.

MeSH Terms

  • Animals
  • Atrial Fibrillation / therapy
  • Atrial Fibrillation / veterinary
  • Electric Countershock / veterinary
  • Electrocardiography / veterinary
  • Heart Atria
  • Horse Diseases / therapy
  • Horses
  • Quinidine

Grant Funding

  • 1S56217N / Research Foundation Flanders
  • 2200674 / The Swedish Heart-Lung Foundation
  • DFF-7017-00050 / Det Frie Forskningsråd
  • BOF.BAS.2018.0022.01 / Special Research Fund Ghent University
  • DFF-7017-00050 / Independent Research Fund Denmark

Conflict of Interest Statement

No competing interests have been declared.

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Citations

This article has been cited 3 times.
  1. Nissen SD, Bastrup JA, Haugaard SL, Marion-Knudsen R, Schneider M, Kjeldsen ST, Carstensen H, Hopster-Iversen C, Nattel S, Jepps TA, Buhl R. Horse model of spontaneous atrial fibrillation share proteomic changes with humans. Sci Rep 2025 Aug 28;15(1):31694.
    doi: 10.1038/s41598-025-16885-7pubmed: 40877415google scholar: lookup
  2. Burns JJ, MacMillan KM, John EE. Retrospective review of atrial fibrillation in Standardbred racehorses at a tertiary care facility in Atlantic Canada. Can Vet J 2022 Oct;63(10):1051-1056.
    pubmed: 36185789
  3. Kjeldsen ST, Nissen SD, Buhl R, Hopster-Iversen C. Paroxysmal Atrial Fibrillation in Horses: Pathophysiology, Diagnostics and Clinical Aspects. Animals (Basel) 2022 Mar 10;12(6).
    doi: 10.3390/ani12060698pubmed: 35327097google scholar: lookup
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