[Effects of Antihypertensive Treatment on the Thickening of the Basal Portion of the Interventricular Septum in Essential Hypertension]

Previous echocardiographic studies have indicated that the basal portion of interventricular septum is locally thickened in many patients with essential hypertension. This retrospective study investigated whether this localized thickening is decreased by antihypertensive treatment. Twenty-four patients with mild essential hypertension (15 males, 9 females, mean [+/- SD] 55 +/- 9 years) were selected who had local thickening at the basal portion of interventricular septum (> or = 11 mm) on echocardiograms recorded within 3 months after the first visit and were followed up by echocardiography 6 months or more after the start of antihypertensive treatment. Interventricular septal wall thickness at the mid portion (IVST), posterior wall thickness (PWT), left ventricular mass index (LVMI), aorto-septal angle, blood flow velocity in left ventricular outflow tract, and the thickness of the basal portion of interventricular septum (septal wall maximum thickness within 1.5 cm apex side from the joint of interventricular septum and aorta in the long-axis view of B-mode echocardiograms) were measured. Blood pressure was significantly decreased from 152.7 +/- 8.7/93.1 +/- 8.0 mmHg to 140.0 +/- 8.2/86.6 +/- 8.2 mmHg by treatment (p < 0.0001). The thickness of the basal interventricular septum was significantly reduced by treatment from 12.3 +/- 1.7 mm to 10.3 +/- 1.4 mm (p < 0.0001). Mean IVST, PWT and LVMI were slightly reduced by treatment, but the differences were not statistically significant. These results suggest that the thickening of basal interventricular septum is induced by high blood pressure, and the measurement of the thickness of basal interventricular septum might be a useful tool to estimate and monitor the effect of antihypertensive treatment in patients with mild essential hypertension.