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Home / Equine Research Bank / J Vet Intern Med / Electrocardiographic characteristics of trained and untraine...
Journal of veterinary internal medicine2022; 36(3); 1119-1130; doi: 10.1111/jvim.16427

Electrocardiographic characteristics of trained and untrained standardbred racehorses.

Abstract: Long-term exercise induces cardiac remodeling that potentially influences the electrical properties of the heart. Objective: We assessed whether training alters cardiac conduction in Standardbred racehorses. Methods: Two hundred one trained and 52 untrained Standardbred horses. Methods: Cross-sectional study. Resting ECG recordings were analyzed to assess heart rate (HR) along with standard ECG parameters and for identification of atrial and ventricular arrhythmias. An electrophysiological study was performed in 13 horses assessing the effect of training on sinoatrial (SA) and atrioventricular (AV) nodal function by sinus node recovery time (SNRT) and His signal recordings. Age and sex adjustments were implemented in multiple and logistic regression models for comparison. Results: Resting HR in beats per minute (bpm) was lower in trained vs untrained horses (mean, 30.8 ± 2.6 bpm vs 32.9 ± 4.2 bpm; P = .001). Trained horses more often displayed second-degree atrioventricular block (2AVB; odds ratio, 2.59; P = .04). No difference in SNRT was found between groups (n = 13). Mean P-A, A-H, and H-V intervals were 71 ± 20, 209 ± 41, and 134 ± 41 ms, respectively (n = 7). We did not detect a training effect on AV-nodal conduction intervals. His signals were present in 1 horse during 2AVB with varying H-V interval preceding a blocked beat. Conclusions: We identified decreased HR and increased frequency of 2AVB in trained horses. In 5 of 7 horses, His signal recordings had variable H-V intervals within each individual horse, providing novel insight into AV conduction in horses.
© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
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Publication Date: 2022-04-30 PubMed ID: 35488721PubMed Central: PMC9151491DOI: 10.1111/jvim.16427Google 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 investigates the impact of long-term exercise on the electrical properties of the heart in Standardbred racehorses. The study finds that training indeed does affect these properties, notably reducing heart rate and increasing the frequency of second-degree atrioventricular block (2AVB).

Methodology

  • The study involved 201 trained Standardbred racehorses and 52 untrained ones. The use of a large number of horses allows for a more robust and reliable analysis of data.
  • The researchers performed a cross-sectional study, meaning they collected data from the horses at one point in time.
  • The researchers analyzed resting ECG (electrocardiogram) recordings to assess heart rate and other standard ECG parameters. They also identified any atrial and ventricular arrhythmias, which are abnormal heart rhythms.
  • The study conducted an electrophysiological study on 13 horses to assess the effect of training on the sinoatrial (SA) node and atrioventricular (AV) node by measuring sinus node recovery time (SNRT) and recording His signals. The SA node and AV node are components of the heart’s electrical system, controlling heart rhythm.
  • Data was adjusted for age and sex in multiple and logistic regression models before comparison.

Results

  • Trained horses had a lower resting heart rate in beats per minute (bpm) than untrained horses.
  • Trained horses exhibited second-degree atrioventricular block (2AVB), a type of heart block, more often than untrained horses.
  • No difference in sinus node recovery time (SNRT) was found between the two groups.
  • The researchers did not detect a training effect on atrioventricular (AV) nodal conduction intervals, suggesting the nodes’ function remained consistent regardless of training.
  • Out of the horses studied, in one case His signals, electrical signals within the heart, were present during a 2AVB event.

Conclusions

  • Trained horses were found to exhibit a decreased heart rate and an increased frequency of second-degree atrioventricular block (2AVB) compared to untrained ones.
  • The researchers made novel observations regarding variable H-V intervals, or variations in the timings within electrical conduction of the heart, in His signals among the trained horses.

This paper provides valuable insights into the changes in cardiac functioning and rhythm by long-term exercise, particularly beneficial for racehorses’ health management and welfare.

Cite This Article

APA
Nissen SD, Weis R, Krag-Andersen EK, Hesselkilde EM, Isaksen JL, Carstensen H, Kanters JK, Linz D, Sanders P, Hopster-Iversen C, Jespersen T, Pehrson S, Buhl R. (2022). Electrocardiographic characteristics of trained and untrained standardbred racehorses. J Vet Intern Med, 36(3), 1119-1130. https://doi.org/10.1111/jvim.16427

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 36
Issue: 3
Pages: 1119-1130

Researcher Affiliations

Nissen, Sarah D
  • Laboratory of Cardiac Physiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Weis, Rikke
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Krag-Andersen, Elisabeth K
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Hesselkilde, Eva M
  • Laboratory of Cardiac Physiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Isaksen, Jonas L
  • Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
Carstensen, Helena
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Kanters, Jørgen K
  • Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
Linz, Dominik
  • Laboratory of Cardiac Physiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
  • Department of Cardiology, Maastricht University Medical Center, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
  • Department of Cardiology, Radboud University Medical Center, Nijmegen, The Netherlands.
  • Centre for Heart Rhythm Disorders, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia.
Sanders, Prashanthan
  • Centre for Heart Rhythm Disorders, University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia.
Hopster-Iversen, Charlotte
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.
Jespersen, Thomas
  • Laboratory of Cardiac Physiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Pehrson, Steen
  • Department of Cardiology 2142, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Denmark.
Buhl, Rikke
  • Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Taastrup, Denmark.

MeSH Terms

  • Animals
  • Arrhythmias, Cardiac / veterinary
  • Cross-Sectional Studies
  • Electrocardiography / veterinary
  • Heart Atria
  • Heart Rate / physiology
  • Horse Diseases / diagnosis
  • Horses

Grant Funding

  • NNF18SA0034956 / Novo Nordisk Foundation
  • Bru00f8drene Hartmanns Fond

Conflict of Interest Statement

Authors declare no conflict of interest.

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Citations

This article has been cited 17 times.
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