Left ventricular (LV) diastolic performance was evaluated with pulsed-wave Doppler echocardiography in a cross-sectional population of patients with systemic lupus erythematosus (SLE) in search of subclinical myocardial involvement. Such involvement is reported to occur infrequently, despite pathohistologic evidence of myocarditis in up to 70% of patients with SLE. Thirty-five consecutive patients with SLE were evaluated, 14 with active and 21 with inactive disease, and were compared with 30 age-matched healthy control subjects. Twenty-six patients were restudied at 7 months. All had normal LV systolic function, normal pericardial and valvular structures, and no significant valvular regurgitation on Doppler echocardiography. In SLE patients with active disease, indexes of LV diastolic function differed significantly from the inactive group and from control subjects, with marked prolongation of isovolumic relaxation time (104 +/- 18 vs 74 +/- 13 ms, p = 0.0001), as well as reduced peak early diastolic filling velocity (E) (0.69 +/- 0.19 vs 0.83 +/- 0.17 ms, p = 0.01), reduced ratio of early to late diastolic flow velocity (E/A) (1.15 +/- 0.53 vs 1.47 +/- 0.35, p = 0.02), and prolonged mitral pressure halftime (74 +/- 14 vs 65 +/- 8 ms p = 0.01). Similar significant differences were found between the active and inactive SLE patient groups. SLE patients with inactive disease differed from control subjects in only mild prolongation of mitral pressure halftime. Abnormal prolongation of isovolumic relaxation (greater than 100 ms) was found to be the most useful marker of diastolic impairment, being present in 64% of SLE patients with active disease and in 14% of patients with inactive disease.(ABSTRACT TRUNCATED AT 250 WORDS)