[B-mode, M-mode and Doppler sonographic findings in mitral valve insufficiency of horses]

B- and M-mode echocardiography was performed on 38 horses. 34 patients had systolic heart murmur with the point of maximal intensity over mitral valve. Additionally, 17 of these patients were examined with the pulsed wave doppler echocardiography (Vingmed 200). In 26 patients with cardiac murmur and in 4 patients without cardiac murmur a mitral valve insufficiency was diagnosed by echocardiography. In 8 horses with a systolic murmur over mitral valve M- and B-mode evaluation could not reveal a haemodynamic importance of the murmur. The diagnosis of MVI was based on a dilation of left atrium with or without additional dilation of left ventricle on one hand and with a regurgitation of blood into left atrium found by pulsed wave doppler on the other hand. In 6 extremely dilated hearts a "real" ostium of regurgitation was detected as a direct echocardiographic finding in B-mode. Good correlations existed between echocardiographically evaluated changes of heart dimensions and autopsy measurements in 10 cases. The prognosis seems to be poor if systolic murmurs coincide with dilatation of left atrium and left ventricle, regurgitation of blood into left atrium or with a high degree dilation of left atrium without changes of left ventricle chamber size. In hearts with little to medium dilated left atrium without changes of left ventricle dimension and additionally a regurgitation into left atrium the prognosis seems at least to be cautious. Echocardiography is an available diagnostic help in evaluation of the importance of systolic murmur with the point of maximal intensity over the mitral valve especially in completion by pulsed wave doppler.