Cardiac electrophysiological adaptations in the equine athlete-Restitution analysis of electrocardiographic features.
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Authors
Li, Mengye
Chadda, Karan R
Matthews, Gareth DK
Marr, Celia M
Huang, Christopher L-H
Publication Date
2018Journal Title
PLoS One
ISSN
1932-6203
Publisher
Public Library of Science (PLoS)
Volume
13
Issue
3
Pages
e0194008
Language
eng
Type
Article
Physical Medium
Electronic-eCollection
Metadata
Show full item recordCitation
Li, M., Chadda, K. R., Matthews, G. D., Marr, C. M., Huang, C. L., & Jeevaratnam, K. (2018). Cardiac electrophysiological adaptations in the equine athlete-Restitution analysis of electrocardiographic features.. PLoS One, 13 (3), e0194008. https://doi.org/10.1371/journal.pone.0194008
Abstract
Exercising horses uniquely accommodate 7-8-fold increases in heart rate (HR). The present experiments for the first time analysed the related adaptations in action potential (AP) restitution properties recorded by in vivo telemetric electrocardiography from Thoroughbred horses. The horses were subjected to a period of acceleration from walk to canter. The QRS durations, and QT and TQ intervals yielded AP conduction velocities, AP durations (APDs) and diastolic intervals respectively. From these, indices of active, λ = QT/(QRS duration), and resting, λ0 = TQ/(QRS duration), AP wavelengths were calculated. Critical values of QT and TQ intervals, and of λ and λ0 at which plots of these respective pairs of functions showed unity slope, were obtained. These were reduced by 38.9±2.7% and 86.2±1.8%, and 34.1±3.3% and 85.9±1.2%, relative to their resting values respectively. The changes in λ were attributable to falls in QT interval rather than QRS duration. These findings both suggested large differences between the corresponding critical (129.1±10.8 or 117.4±5.6 bpm respectively) and baseline HRs (32.9±2.1 (n = 7) bpm). These restitution analyses thus separately identified concordant parameters whose adaptations ensure the wide range of HRs over which electrophysiological activation takes place in an absence of heart block or arrhythmias in equine hearts. Since the horse is amenable to this in vivo electrophysiological analysis and displays a unique wide range of heart rates, it could be a novel cardiac electrophysiology animal model for the study of sudden cardiac death in human athletes.
Keywords
Action Potentials, Adaptation, Physiological, Animals, Electrocardiography, Female, Heart Conduction System, Horses, Male, Physical Conditioning, Animal, Running, Telemetry, Walking
Sponsorship
Medical Research Council (MR/M001288/1)
Wellcome Trust (105727/Z/14/Z)
British Heart Foundation (None)
Identifiers
External DOI: https://doi.org/10.1371/journal.pone.0194008
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280035
Rights
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/
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