This study was aimed at investigating abnormalities in left ventricular size and function in patients with systemic lupus erythematosus without overt cardiovascular manifestations, in order to detect a very early impairment in myocardial function. Seventeen females and 1 male with systemic lupus erythematosus of 4 to 20 year duration and without clinical evidence of heart disease were studied. Twelve healthy volunteers, matched for age, sex and quatelet index, were utilized as controls. Each patient had a two-dimensional M-mode echocardiographic and Doppler examination. In patients with systemic lupus erythematosus there was an increase in left ventricular ejection fraction (p < 0.001), a slight reduction of end-diastolic volume index and a significant decrease of end-systolic volume index (p < 0.001). In the same patients we also found prolongation of the isovolumic relaxation time (p < 0.02), a clear impairment of diastolic filling parameters. Peak E velocity was lower (p < 0.01), peak A velocity was higher (p < 0.01), with a clear lowering, of the corresponding E/A ratio (p < 0.001) in patients with systemic lupus erythematosus.