Diurnal modulation and sources of variation affecting ventricular repolarization in Warmblood horses.
Abstract: Irregularities in cardiac repolarization are known to predispose for arrhythmias and sudden cardiac death in humans. The QT interval is a quantitative measurement of repolarization, and clinically, the QTc (QT interval corrected for heart rate) and Tpeak to Tend intervals (TpTe) are used as repolarization markers. To support the use of these markers in horses, we sought to describe the possible influence of the environment, time of day, day-to-day effects, T wave conformation, age, body weight (BW), and horse-to-horse variation on repolarization measurements. Methods: 12 Warmblood geldings, age 10.8 ± 4.8 years. Methods: Holter ECGs were performed on days 0, 7 and 14. Measures of RR, QT, QTp, QTc and TpTe intervals and T wave conformation were obtained each hour during the recordings. An ANCOVA analysis was performed to estimate diurnal variation and the sources of variation affecting these intervals. Results: Differences between individual horses were the largest source of repolarization variability although the environment had a significant effect on repolarization as well. Diurnal variation affected both the RR interval and the repolarization markers. The QT, QTc and TpTe intervals were prolonged on day 0. Biphasic T waves shortened the TpTe interval approximately 10 ms. Age and BW did not appear to affect repolarization. Conclusions: Equine repolarization markers exhibit significant variation. Factors affecting repolarization measurements include horse-to-horse variation, diurnal variation, the environment, and T wave conformation. These factors must be considered if markers of equine repolarization are used diagnostically.
Copyright © 2014 Elsevier B.V. All rights reserved.
Publication Date: 2014-07-27 PubMed ID: 25278426DOI: 10.1016/j.jvc.2014.07.001Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- 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.
The study analyses factors affecting heart irregularities, measured through repolarization, in Warmblood horses. It determines the relevance of markers such as the QT interval in equine veterinary care and identifies horse-specific variation, diurnal variation, environmental factors, and T wave conformation as significant influencers.
Objective and Background
- The research aimed to understand the factors affecting ventricular repolarization, a critical heart measure in Warmblood horses. This was done by examining the effect of various factors like the environment, time of the day, daily effects, T wave formation, age, and body weight on repolarization measurements.
- The background of the study lies in understanding that irregularities in cardiac repolarization may lead to heart arrhythmias and sudden cardiac death in humans. The QT interval provides a quantitative measurement of this repolarization. The clinical markers for repolarization are the corrected QT interval (QTc) and the Tpeak to Tend intervals (TpTe).
Methodology
- 12 Warmblood geldings (neutered male horses), all aged about 11 years, were selected for the study.
- Holter ECGs were performed on predetermined days (0, 7, and 14) to measure RR, QT, QTp, QTc and TpTe intervals and T wave conformation every hour.
- An ANCOVA analysis was performed on these measurements to determine diurnal variation and the source of variation affecting these intervals.
Results
- The primary source of variability in repolarization came from differences between individual horses. However, the environment also played a significant role in affecting repolarization.
- The study found diurnal variations in the RR interval and repolarization markers, with QT, QTc, and TpTe intervals seeing a prolongation on day 0.
- The TpTe interval seemed to shorten by approximately 10 ms during biphasic T waves.
- Neither age nor body weight seemed to have any significant effect on repolarization.
Conclusion
- Equine repolarization measurements showed variation, influenced largely by individual variation between the horses, diurnal variation, the environment, and T wave conformation.
- The researchers concluded that these factors should be taken into account when using repolarization markers for diagnostic purposes in horses.
Cite This Article
APA
Pedersen PJ, Moeller SB, Flethøj M, Kanters JK, Buhl R, Klaerke DA.
(2014).
Diurnal modulation and sources of variation affecting ventricular repolarization in Warmblood horses.
J Vet Cardiol, 16(4), 265-276.
https://doi.org/10.1016/j.jvc.2014.07.001 Publication
Researcher Affiliations
- Department of Veterinary Clinical and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 100, 1870 Frederiksberg C, Denmark. Electronic address: philip@sund.ku.dk.
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Agrovej 8, 2630 Taastrup, Denmark.
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Agrovej 8, 2630 Taastrup, Denmark.
- Laboratory of Experimental Cardiology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Koebenhavn N, Denmark; Department of Cardiology, Herlev and Gentofte University Hospitals, Denmark.
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Agrovej 8, 2630 Taastrup, Denmark.
- Department of Veterinary Clinical and Animal Science, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlaegevej 100, 1870 Frederiksberg C, Denmark.
MeSH Terms
- Animals
- Atrioventricular Block
- Circadian Rhythm / physiology
- Electrocardiography, Ambulatory / veterinary
- Horses / physiology
- Male
- Parasympathetic Nervous System / physiology
- Sinoatrial Block
- Ventricular Function / physiology
Citations
This article has been cited 3 times.- 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. Electrocardiographic characteristics of trained and untrained standardbred racehorses.. J Vet Intern Med 2022 May;36(3):1119-1130.
- Cosgun A, Oren H. Variation of the T-wave peak-end interval and heart rate variability values in healthy males and females at various hours of the same day, and relationship of them.. J Arrhythm 2020 Feb;36(1):118-126.
- Pedersen PJ, Thomsen KB, Olander ER, Hauser F, Tejada Mde L, Poulsen KL, Grubb S, Buhl R, Calloe K, Klaerke DA. Molecular Cloning and Functional Expression of the Equine K+ Channel KV11.1 (Ether à Go-Go-Related/KCNH2 Gene) and the Regulatory Subunit KCNE2 from Equine Myocardium.. PLoS One 2015;10(9):e0138320.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
