title: Effect of light exercise on valvular regurgitation in standardbred trotters.
abstract: BACKGROUND
  Although valvular regurgitation is diagnosed frequently by colour Doppler echocardiography in racehorses at rest, there is currently no information about the effect of exercise on valvular regurgitation.
  
  
  OBJECTIVE
  To investigate the effect of light exercise on valvular regurgitation in a population of trotters.
  
  
  METHODS
  Standardbred trotters (n = 73) were examined by resting auscultation and echocardiography, of which 50 fullfilled the criteria of the study. Of these, 4 had reduced performance according to the trainers and were not included in the statistical analyses. Horses that showed valvular regurgitations diagnosed by colour Doppler echocardiography at rest, were light exercised and the regurgitant valves were then re-examined by colour Doppler echocardiography.
  
  
  RESULTS
  Of the 46 horses, 41 (89%) had one or more valvular regurgitations at rest with tricuspid regurgitation present in 83% of horses, mitral regurgitation 46%, pulmonary regurgitation 37% and aortic regurgitation 57%. After exercise, one or more valvular regurgitation persisted for 23 of the 41 horses (56%). The regurgitation decreased significantly for mitral, pulmonary and aortic valves; the mitral regurgitation persisted for 21% of the horses, pulmonary regurgitation persisted for 6% and aortic regurgitation persisted after exercise for 23 % with regurgitation diagnosed at rest. Half of those with tricuspid regurgitation at rest still had tricuspid regurgitation after exercise.
  
  
  CONCLUSIONS
  The results of this study showed that the majority of small valvular regurgitations disappear after light exercise. However, the severity of tricuspid regurgitation increased in 4 horses. Furthermore, these horses were not performing satisfactorily according to the trainers.
  
  
  CONCLUSIONS
  Studies in man have shown that severity after exercise suggests pathological regurgitation. The present study indicates that echocardiographic examination of valvular regurgitation after exercise might be a relevant examination in horses. However, more studies are needed to evaluate the effect of strenuous exercise on valvular regurgitation in horses.
authors.affiliation: Department of Large Animal Sciences, The Royal Veterinary andAgricultural University, 48 Dyrlaegevej, DK- 1870 Frederiksberg C, Denmark.
authors.forename: R
authors.initials: R
authors.lastname: Buhl
authors.forename: A K
authors.initials: AK
authors.lastname: Ersbøll
mesh_terms: D000818:Animals; D018618:Echocardiography, Doppler, Color / Q000379:methods / Q000662:veterinary*; D005081:Exercise Therapy; D005260:Female; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy / Q000662:veterinary*; D006734:Horse Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy*; D006736:Horses; D008297:Male; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy / Q000662:veterinary; D010805:Physical Conditioning, Animal / Q000502:physiology*; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy / Q000662:veterinary