The Eisenmenger syndrome has been associated with right ventricular (RV) enlargement and systolic dysfunction. However, little attention has been directed toward potentially characteristic changes in left ventricular (LV) dimensions or function. Therefore, 2-dimensional echocardiography (short-axis-papillary muscle level) was performed in 24 adults (mean age 33 +/- 7 years) with Eisenmenger syndrome to evaluate RV and LV size and function. A significant correlation was found between RV and LV end-diastolic areas (r = 0.96; regression slope 1.06), and fractional area change (r = 0.88; regression slope 1.03) in patients with a nonrestrictive ventricular septal defect (VSD) (n = 15). In contrast, in patients with Eisenmenger syndrome but no VSD (n = 9), RV and LV end-diastolic areas (r = 0.68; regression slope 0.10), and fractional area change (r = 0.08; regression slope -0.09) were discordant. RV function was preserved in most patients with a VSD, and mean RV fractional area change was significantly greater than in those without a VSD (0.50 +/- 0.13 vs 0.18 +/- 0.08; p < 0.001). No significant difference was apparent in these 2 groups (patients with and without a VSD) with respect to age, pulmonary artery systolic pressure, partial arterial oxygen pressure or hematocrit. Thus, the results indicate a relation between biventricular chamber dimensions and systolic function that is dependent on the nature and locus of the primary intracardiac defect responsible for the Eisenmenger syndrome.