ABSTRACT: Background:Transesophageal echocardiography (TEE) has not been compared to transthoracic echocardiography (TTE) for assessment of left ventricular diastolic function (LVDF). Left ventricular diastolic dysfunction is common in systemic lupus erythematosus (SLE), a disease model of premature myocardial disease. Methods:66 patients with SLE (mean age 36±12 years, 91% women) and 26 age-and-sex matched healthy volunteers (mean age 34±11 years, 85% women) underwent TEE immediately followed by TTE. From basal four-chamber views, mitral inflow E and A velocities, E/A ratio, E deceleration time, isovolumic relaxation time, septal and lateral mitral E' and A' velocities, septal E'/A' ratio, mitral E to septal and lateral E' ratios, and pulmonary veins systolic to diastolic peak velocities ratio were measured. Measurements were averaged over 3 cardiac cycles and performed by 2 independent observers. Results:LVDF parameters were worse in patients than in controls by TEE and TTE (all p?0.03). Most LVDF parameters were similar within each group by TEE and TTE (all p?0.17). By both techniques, mitral E and A, mitral and septal E/A ratios, septal and lateral E', septal and lateral E/E' ratios, and average E/E' ratio were highly correlated (r=0.64-0.96, all p?0.003); E deceleration time, isovolumic relaxation time, and septal A' velocities were moderately correlated (r=0.43-0.54, all p?0.03); and pulmonary veins systolic to diastolic ratio showed the lowest correlation (r=0.27, p=0.04). Conclusion:By TEE and TTE, LVDF parameters were worse in SLE patients than in controls; and in both groups, LVDF parameters assessed by TEE and TTE were similar and significantly correlated.