To investigate whether the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E') (E/E' ratio) can detect left ventricular diastolic dysfunction more sensitively than the ratio of E to mitral peak velocity of late filling (A) (E/A ratio) in systemic lupus erythematosus (SLE). A total of 137 patients with SLE were investigated and compared with 110 age-matched and sex-matched controls retrospectively. Two-dimensional echocardiography and M-mode echocardiography including conventional and tissue Doppler imaging were performed. There were no differences in the left ventricle ejection fractions and the mean E/A ratio between the two groups. However, the mean E/E' ratio of patients was higher than that of the controls (10.4 +/- 4.0 vs 7.7 +/- 2.1, P < 0.01). Significantly higher left ventricle ejection fractions and lower E/E' ratio were found in patients with systemic lupus erythematosus receiving angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker than those not receiving (P < 0.05). Our study showed that the E/E' ratio is more sensitive than the E/A ratio for detection of the left ventricle diastolic dysfunction. Furthermore, patients who had received angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker treatment showed significantly better preservation of both systolic and diastolic function of left ventricle in comparison with those who had not received.