Utilzzo dei parametri ecocardiografici tradizionali ed a Doppler tissutale nella valutazione della disfunzione atrio-ventricolare in cani affetti da malattia mitralica cronica

The aim of this study is to evaluate the atrioventricular function using brand new echocardiographic techniques, such as Tissue Doppler Imaging (TDI) in dogs affected by chronic mitral valve disease (MVD). The first part of the project is focused on the analysis of right ventricular function in dogs affected by left sided heart failure, in order to better understand if the dysfunction of one ventricle might interfere with the function of the contralateral one. The main results were: absence of significance sisto-diastolic right ventricular dysfunction in dogs with different stages of MVD; direct relationship between right ventricular TDI variables and left ventricular functional parameters; lastly, the presence of more severe left ventricular diastolic abnormalities in patients with different degrees of pulmonary hypertension. In particular, the TDI variable mitral annulus E/e' ratio was directly correlated to pulmonary artery pressures and was a useful indicator in predicting presence of this condition. In the second study we used TDI to analyze global and regional function of the left atrium in normal dogs and in dogs with MVD and different degrees of left atrial dilation. The results showed that left atrial TDI is feasible and reproducible in dogs and we proposed some ranges of normality for this specie. We found a few differences in TDI left atrial variables between normal and diseased animals, however we identified some correlations between TDI parameters and the traditional echocardiographic left atrial functional variables (such as left atrial diameter, transmitral waves flow velocity). In conclusion we verified that new TDI based echocardiographic techniques are useful in the noninvasive evaluation of segmental cardiac function in normal and diseased dogs.