Endogenous ouabain and hemodynamic and left ventricular geometric patternsin essential hypertension

We sought to evaluate the relationships among circulating levels of an endo genous ouabain-like factor (EO) and systemic hemodynamics and left ventricu lar (LV) geometry in patients with recently diagnosed essential hypertensio n. We selected 92 never-treated patients with essential hypertension. Blood samples were drawn for estimation of plasma EO (radioimmunoassay) and subj ects underwent echocardiographic examination to evaluate LV end-systolic an d end-diastolic wall thickness and internal dimensions. LV volumes, stroke volume, cardiac output, total peripheral resistance, LV mass, and relative wall thickness were calculated, and all except the last parameter were inde xed by body surface area. LV mass also was indexed by height(2.7). On the b asis of the values of LV mass index (body surface area or height(2.7)) and relative wall thickness, subjects were divided into groups with either norm al geometry, concentric remodeling, concentric hypertrophy, or eccentric no ndilated hypertrophy. In the study population as a whole, circulating EO le vels were significantly and directly correlated with mean blood pressure (r = 0.21, P =.048), relative wall thickness (r = 0.34, P =.001), and total p eripheral resistance index (r = 0.37, P =.0003). Plasma EO also was signifi cantly and inversely correlated with LV end-diastolic volume index (r = -0. 32, P =.002), stroke index (r = -0.34, P =.0009), and cardiac index (r = -0 .35, P =.0007). In multiple regression analysis, plasma EO was an independe nt correlate of total peripheral resistance index, cardiac index, and relat ive wall thickness. Regardless of the indexation method used for LV mass, p lasma EO was higher in patients with concentric remodeling than in those wi th either normal geometry or concentric hypertrophy. Plasma EO tended to be higher (indexation by body surface area) or was significantly higher (inde xation by height2.7) in subjects with concentric remodeling than in those w ith eccentric nondilated hypertrophy. Patients with concentric remodeling s howed the highest total peripheral resistance index and the lowest cardiac index. Our data suggest that EO plays a role in regulating systemic hemodyn amics and LV geometry in patients with essential hypertension. (C) 2001 Ame rican Journal of Hypertension, Ltd.