Abstract
Background: Heart rate variability (HRV) analysis measures the inter-beat interval variation of successive cardiac cycles. Measurement of these indices has been used to assess cardiac autonomic modulation and for arrhythmia identification in exercising horses.
Objectives: To report HRV indices during submaximal exercise, strenuous exercise and recovery, and explore relationships with clinical conditions (arrhythmias, lameness, equine gastric ulcer syndrome (EGUS), lower airway inflammation and upper respiratory tract obstructions (URTO) in Thoroughbred (TB) racehorses.
Study Design: Retrospective, observational cross-sectional study.
Methods: One hundred and eighty Thoroughbred horses underwent a treadmill exercise test with simultaneous electrocardiographic (ECG) recording. Time-domain HRV indices (standard deviation of the R-R interval (SDRR); root mean square of successive differences (RMSSD)) were derived for submaximal and strenuous exercise and recovery segments. Clinical conditions (arrhythmia (during each phase of exercise), lameness, EGUS, lower airway inflammation and URTO) were assigned to binary categories for statistical analysis. Relationships between selected HRV indices and the clinical conditions were explored using linear regression models.
Results: During submaximal exercise, lameness was associated with decreased logRMSSD (B= -0.19 95% CI -0.31 to -0.06, P= 0.006) and arrhythmia was associated with increased logRMSSD (B= 0.31 95% CI 0.01-.608, P=0.04). During strenuous exercise, arrhythmia was associated with increased HRV indices (logSDRR B= 0.51 95% CI 0.40-0.62, P
Main Limitations: The main limitations of this retrospective study were that not every horse had the full range of clinical testing, therefore some horses may have had undetected abnormalities.
Conclusions: The presence of arrhythmia increased HRV in both phases of exercise and recovery. Lameness decreased HRV during submaximal exercise.
Objectives: To report HRV indices during submaximal exercise, strenuous exercise and recovery, and explore relationships with clinical conditions (arrhythmias, lameness, equine gastric ulcer syndrome (EGUS), lower airway inflammation and upper respiratory tract obstructions (URTO) in Thoroughbred (TB) racehorses.
Study Design: Retrospective, observational cross-sectional study.
Methods: One hundred and eighty Thoroughbred horses underwent a treadmill exercise test with simultaneous electrocardiographic (ECG) recording. Time-domain HRV indices (standard deviation of the R-R interval (SDRR); root mean square of successive differences (RMSSD)) were derived for submaximal and strenuous exercise and recovery segments. Clinical conditions (arrhythmia (during each phase of exercise), lameness, EGUS, lower airway inflammation and URTO) were assigned to binary categories for statistical analysis. Relationships between selected HRV indices and the clinical conditions were explored using linear regression models.
Results: During submaximal exercise, lameness was associated with decreased logRMSSD (B= -0.19 95% CI -0.31 to -0.06, P= 0.006) and arrhythmia was associated with increased logRMSSD (B= 0.31 95% CI 0.01-.608, P=0.04). During strenuous exercise, arrhythmia was associated with increased HRV indices (logSDRR B= 0.51 95% CI 0.40-0.62, P
Main Limitations: The main limitations of this retrospective study were that not every horse had the full range of clinical testing, therefore some horses may have had undetected abnormalities.
Conclusions: The presence of arrhythmia increased HRV in both phases of exercise and recovery. Lameness decreased HRV during submaximal exercise.
| Original language | English |
|---|---|
| Pages (from-to) | 727-737 |
| Number of pages | 11 |
| Journal | Equine Veterinary Journal |
| Volume | 55 |
| Issue number | 5 |
| Early online date | 20 Dec 2022 |
| DOIs | |
| Publication status | Published - 1 Sept 2023 |
Bibliographical note
Funding Information:This study was performed in the University of Bristol's Equine Sports Medicine Department and the authors thank all the staff involved in collection of this data. The authors also thank Klaus Engel from Engel Engineering Services who provided invaluable support with Televet 100. Langford Trust funded part of the study and Beaufort Cottage Educational Trust funded W. Sage.
Publisher Copyright:
© 2022 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.