Of the three physiopathological types of cardiomyopathy, dilated, hypertrophic and restrictive, it is the first which characteristically shows major left ventricular systolic dysfunction. The left ventricular volumes are increased, the ventricle becomes spherical and global ejection fraction decreases with diffuse or segmental wall motion abnormalities. The left ventricular mass is increased in an excentrical fashion with wall thinning. Isovolumic contraction is slower, the ejection time is shorter and, above all, the indices of contractility such as maximal velocity of the contractile elements ... are very abnormal and do not improve after positive inotropic stimulation.