Altered systolic left ventricular function in horses completing a long distance endurance race
Article first published online: 8 NOV 2010
© 2010 EVJ Ltd
Equine Veterinary Journal
Special Issue: Proceedings of the 8th International Conference on Equine Exercise Physiology
Volume 42, Issue Supplement s38, pages 216–219, November 2010
How to Cite
AMORY, H., VOTION, D.-M., FRAIPONT, A., GOACHET, A. G., ROBERT, C., FARNIR, F. and VAN ERCK, E. (2010), Altered systolic left ventricular function in horses completing a long distance endurance race. Equine Veterinary Journal, 42: 216–219. doi: 10.1111/j.2042-3306.2010.00253.x
- Issue published online: 8 NOV 2010
- Article first published online: 8 NOV 2010
- [Paper received for publication 09.01.10; Accepted 28.05.10]
- long duration exercise;
- systolic function;
- cardiac fatigue;
Reasons for performing study: It is unknown whether or not exercise-induced cardiac fatigue (EICF), as demonstrated in human athletes performing long duration exercise, occurs in endurance horses.
Objective: To examine the effects of a long distance endurance race on left ventricular systolic function in horses.
Methods: Echocardiography was performed before, and after, a 2 or 3 star international endurance race (106–132 km) in 11 horses. Systolic (s) and diastolic (d) interventricular and left ventricular free wall thickness (IVS and LVFW, respectively), left ventricular, left atrial and aortic internal diameter (LVID, LA and Ao, respectively), fractional shortening (FS) and ejection fraction (EF) were measured by echocardiography. Heart rate (HR), peak flow velocity (Vmax), flow velocity integral (FVI), ejection time (ET), pre-ejection period (PEP), velocity of circumferential fibre shortening (Vcf), stroke volume (SV) and cardiac output (CO) were measured from aortic Doppler wave recordings.
Results: After the race, LVIDd, Ao, LA, EF, FS, FVI, SV, ET and ET indexed for HR were significantly lower and IVSd, LVFWd, HR, PEP, PEP/ET and Vcf significantly higher as compared with prerace values. Pre- to post exercise changes in those parameters were not significantly correlated with changes in HR or in LVIDd.
Conclusions: Results suggest that EICF, with a decrease in left ventricular systolic function, could occur post exercise in horses performing long duration endurance races. However, a multanecus effect of altered preload and heart rate on the studied variables cannot be discounted.