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Home / Equine Research Bank / BMC Vet Res / Appropriate threshold levels of cardiac beat-to-beat variati...
BMC veterinary research2016; 12(1); 266; doi: 10.1186/s12917-016-0894-2

Appropriate threshold levels of cardiac beat-to-beat variation in semi-automatic analysis of equine ECG recordings.

Abstract: Although premature beats are a matter of concern in horses, the interpretation of equine ECG recordings is complicated by a lack of standardized analysis criteria and a limited knowledge of the normal beat-to-beat variation of equine cardiac rhythm. The purpose of this study was to determine the appropriate threshold levels of maximum acceptable deviation of RR intervals in equine ECG analysis, and to evaluate a novel two-step timing algorithm by quantifying the frequency of arrhythmias in a cohort of healthy adult endurance horses. Results: Beat-to-beat variation differed considerably with heart rate (HR), and an adaptable model consisting of three different HR ranges with separate threshold levels of maximum acceptable RR deviation was consequently defined. For resting HRs 100 bpm, the threshold level was 4%. Supraventricular premature beats represented the most prevalent arrhythmia category with varying frequencies in seven horses at rest (median 7, range 2-86) and six horses during exercise (median 2, range 1-24). Conclusions: Beat-to-beat variation of equine cardiac rhythm varies according to HR, and threshold levels in equine ECG analysis should be adjusted accordingly. Standardization of the analysis criteria will enable comparisons of studies and follow-up examinations of patients. A small number of supraventricular premature beats appears to be a normal finding in endurance horses. Further studies are required to validate the findings and determine the clinical significance of premature beats in horses.
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Publication Date: 2016-11-28 PubMed ID: 27894294PubMed Central: PMC5126988DOI: 10.1186/s12917-016-0894-2Google Scholar: Lookup
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  • 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.

The research article is about a study conducted to establish the acceptable levels of variation between heart beats in horses, and test a new method of doing so, with the findings guiding the development of standardized criteria for analyzing equine ECGs.

Research Context

  • The study was motivated by the difficulty in analyzing horse electrocardiograms (ECGs) due to the lack of standardized criteria and insufficient knowledge about natural beat-to-beat variations in equine heart rhythms.
  • Research has shown that premature heartbeats are a cause for concern in horses, adding another dimension to the challenge of equine ECG interpretation.

Study Purpose

  • The research aimed to specify the acceptable maximum deviation threshold of RR intervals (time between two R waves in the ECG signal) in horse ECG evaluations.
  • Another goal was to assess a new two-step timing algorithm by identifying the occurrence rate of heart rhythm disorders in a group of healthy adult endurance horses.

Research Findings

  • The variance in beat-to-beat was found to change significantly with the heart rate (HR).
  • The team developed a user-customizable model comprising three different HR categories, each with individual maximum RR deviation limit. The RR interval deviation threshold was – 20% for resting HRs below 60 beats/min (bpm), 10% for HRs between 60 and 100 bpm, and 4% for exercising HRs above 100 bpm.
  • The most common arrhythmia was premature beats originating from the upper chambers of the heart, occurring with different frequencies in seven resting horses (median 7, range 2-86) and six exercising horses (median 2, range 1-24).

Implications and Future Directions

  • The study concluded that the threshold standards for equine ECG evaluations should adjust in line with HR fluctuations because the beat-to-beat difference in horse cardiac rhythm varies based on HR.
  • Standardization of assessment criteria would help compare outcomes from different studies and monitor patient progress across subsequent examinations.
  • The researchers posit that a small count of premature beats originating above the ventricles is a typical finding in endurance horses.
  • Further investigations are necessary to validate these results and unpack the clinical implications of premature beats in horses.

Cite This Article

APA
Flethøj M, Kanters JK, Pedersen PJ, Haugaard MM, Carstensen H, Olsen LH, Buhl R. (2016). Appropriate threshold levels of cardiac beat-to-beat variation in semi-automatic analysis of equine ECG recordings. BMC Vet Res, 12(1), 266. https://doi.org/10.1186/s12917-016-0894-2

Publication

BMC veterinary research
ISSN: 1746-6148
NlmUniqueID: 101249759
Country: England
Language: English
Volume: 12
Issue: 1
Pages: 266
PII: 266

Researcher Affiliations

Flethøj, Mette
  • Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard Allé 5, 2630, Taastrup, Denmark. flethoj@sund.ku.dk.
Kanters, Jørgen K
  • Laboratory of Experimental Cardiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.
  • Department of Cardiology, Herlev & Gentofte University Hospitals, Copenhagen, Denmark.
Pedersen, Philip J
  • Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 100, 1870, Frederiksberg C, Denmark.
Haugaard, Maria M
  • Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard Allé 5, 2630, Taastrup, Denmark.
Carstensen, Helena
  • Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard Allé 5, 2630, Taastrup, Denmark.
Olsen, Lisbeth H
  • Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Groennegaardsvej 15, 1870, Frederiksberg C, Denmark.
Buhl, Rikke
  • Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard Allé 5, 2630, Taastrup, Denmark.

MeSH Terms

  • Animals
  • Arrhythmias, Cardiac / physiopathology
  • Arrhythmias, Cardiac / veterinary
  • Electrocardiography / veterinary
  • Female
  • Heart Rate
  • Horses / physiology
  • Male
  • Reference Values

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Citations

This article has been cited 3 times.
  1. Frick L, Schwarzwald CC, Mitchell KJ. The use of heart rate variability analysis to detect arrhythmias in horses undergoing a standard treadmill exercise test. J Vet Intern Med 2019 Jan;33(1):212-224.
    doi: 10.1111/jvim.15358pubmed: 30520119google scholar: lookup
  2. Navas de Solis C, Ramseyer A, Stefanovski D, Haughan J, Solomon CJ, Kirsch K. Association of heart rate variability, exercise intensity and exercising arrhythmias with competition results in eventing horses. Equine Vet J 2025 Nov;57(6):1446-1456.
    doi: 10.1111/evj.14491pubmed: 40008417google scholar: lookup
  3. Santosuosso E, Léguillette R, Shoemaker S, Baumwart R, Temple S, Hemmerling K, Kell T, Bayly W. A consort-guided randomized, blinded, controlled clinical trial on the effects of 6 weeks training on heart rate variability in thoroughbred horses. J Vet Intern Med 2025 Jan-Feb;39(1):e17253.
    doi: 10.1111/jvim.17253pubmed: 39655519google scholar: lookup
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