Twenty cases of clinically diagnosed dilatation cardiomyopathy (DCM) were examined with the Model XJY-6 ultrasound instrument to determine the anatomical changes of their hearts and the changes of their left ventricular diastolic function (LVDF) . Twenty healthy individuals were also examined as control. The following results were observed.Most patients exhibited dilatation of all the chambers and the increase of the left ventricular weight, however, dilatation was the main manifestation. Cardiac dilatation and hypertrophy present the similar pictures on radiograph or ECG, differentiation of the two conditions can hardly be made with either of the above methods, but must depend on ultrasound especially in cases complicated with left atrial dilatation and fibrillation.The changes of LVDF of DCM patients revealed by ultrasoundfwere the abnormalities of the amplitude and rate of the posterior wall movement and of the dias-tolic filling volume and filling rate of the left ventricle. It was found that the PWE, DPWV, RFF, RER/ESV of the patients were much lower than those of the control (P