[Age-associated morphological change in interventricular septum].

To investigate the morphological features of the interventricular septum (IVS) in the senile heart, we examined 123 normotensives (59 males and 64 females), ranging in age from 22 to 91 yrs using 2D echocardiography. End-diastolic IVS thickness was measured at the mid-portion (M) and at the thickest portion within 15 mm distal to the aorto-septal junction (basal portion, B) on left parasternal long-axis tomogram. The sigmoid shape of the basal portion was evaluated in terms of aorto-septal (AS) angle. M showed no correlation with age, whereas B increased significantly with age in both sexes (males, r = 0.42, p < 0.01; females, r = 0.51, p < 0.01). B/M ratio, therefore, also increased with age (males, r = 0.49, p < 0.01; females, r = 0.39, p < 0.01). The AS angle decreased with age in both sexes (males, r = -0.33, p < 0.01; females, r = -0.51, p < 0.01). There was a significant inverse correlation between B/M ratio and AS angle (males, r = -0.31, p < 0.05; females, r = -0.50, p < 0.01). We conclude that the B/M ratio is a novel index reflecting heterogenously distributed hypertrophy in the IVS associated with age.