| dc.description.abstract | SUMMARY
Background: Mitral regurgitation in horses is a relatively common clinical finding. It has a physiological form when it does not cause haemodynamic changes and does not affect exercise tolerance. In these cases, the regurgitation is usually mild, and the mitral valve leaflets are normal in appearance. Its pathological form is caused by different structural abnormalities, such as nodular or diffuse degenerative thickening of the leaflets, mitral valve prolapse, bacterial endocarditis or rupture of the chordae tendineae.Objectives: To review the current literature about mitral regurgitation, and present ten clinical cases.Materials and Methods: Ten horses with variable degree of mitral regurgita-tion were included in this retrospective study. Physical examination, two-dimensional, M-mode and colour flow Doppler echocardiography were performed in all cases.Results and Discussion: None of the horses showed signs of congestive heart failure. All animals had a systolic cardiac murmur with variable duration. Seven horses had holo- or pansystolic murmurs, the remaining three horses had a midsystolic, a mid-to-late systolic, and a systolo-diastolic murmur. Intensity of the murmurs varied between 2 and 4 out of 6. The points of maximum intensity of the murmurs were in the left 4th to 5th intercostal spaces. No cardiac arrhyth-mias were detected in the horses during the cardiology workup. Five horses had multiple increased cardiac parameters determined by echocardiography, but most of these were mild, except in three horses, where end-diastolic left atrial, and end-systolic and end-diastolic left ventricular diameters were markedly elevated. Four animals had nodular or diffuse thickening of the mitral valve, one showed mitral valve prolapse, one had a vegetative lesion on the septal leaflet of the mitral valve, and in one case it was not possible to differentiate between chordal rupture and chronic bacterial endocarditis. Four horses showed mild, another four moderate, and the remaining two severe mitral regurgitation determined by colour flow Doppler echocardiography. | en_US |
