Valvular regurgitations, heart murmurs and cardiac dimensions in elite dressage horses

Abstract

OBJECTIVE: To assess the characteristics of heart adaptation and the prevalence of valvular regurgitation and heart murmurs in elite dressage horses. ANIMALS: 15 fit elite (competing at Z2 level and higher) dressage horses and 15 untrained warmblood horses. METHODES: All horses underwent a physical examination, cardiac auscultation and B-Mode, M- Mode and Colour Flow Doppler echocardiography. Dressage horses were further classified by training intensity and competition level to determine possible intensity effects. RESULTS: Healthy and fit dressage horses had a higher prevalence of valvular murmurs of the aorta, mitral and tricuspid valve than horses that were not trained. Also the prevalence of valvular regurgitations of the aorta, mitral and tricuspid valve detected with Doppler echocardiography was higher in the dressage group than in the control group. Right ventricle diameter (RVD), interventricular septum in diastole (IVSd), pulmonary artery diameter (PAD), calculated left ventricle mass (LVmass) and mean wall thickness (MWT) were significantly higher in dressage than control horses. Competition level groups (control, Z2 & ZZ and Prix Saint Georges) differed in IVSd, left ventriculair posterior wall in diastole (LVPWd), E-point to septal separation (EPSS), PAD, LVmass and MWT while training level groups differed in IVSd, LVPWd, EPSS, LVmass and MWT. CONCLUSION: This group of dressage horses did show left sided heart changes especially wall thickness adaptation and showed a higher prevalence of audible murmurs and valvular regurgitations than controls horses.