Changes in ventricular septal thickness during diuretic therapy.

We report on changes in echocardiographic parameters of left ventricular muscle mass in 20 hypertensive patients during short-term therapy with hydrochlorothiazide. In the group as a whole, blood pressure fell, but septal thickness and posterior wall thickness did not change. Septal thickness decreased in nine patients, and in all of these patients calculated left ventricular cross-sectional area also decreased. Septal thickness did not change or increased in 11 patients and in only one of these patients did cross-sectional area increase. These increases in septal thickness usually were associated with decreases in left ventricular transverse dimension. We therefore conclude that the increases in left ventricular wall and septal thickness during diuretic therapy probably reflect an adaptive change of cardiac muscle tissue around a smaller left ventricle.