Effects of labetalol on left ventricular mass and function in hypertension--an assessment by serial echocardiography.

We determined echocardiographic (M-mode) indices of left ventricular mass and function serially at 1-month intervals in 10 patients with uncomplicated mild or moderate essential hypertension, before and after adequate control of blood pressure with labetalol, a combined alpha- and beta-receptor blocking agent. Seven patients had pretreatment echocardiographic evidence of left ventricular hypertrophy with disproportionate septal thickness in 4. Systolic blood pressure in the untreated state correlated well (r = 0.96) with left ventricular mass but poorly (r = 0.30) with diastolic pressure. Following a satisfactory blood pressure reduction, achieved in all patients, left ventricular mass decreased from 240.5 +/- 71.1 g to 159.5 +/- 40.7 g (P less than 0.01), interventricular septal thickness from 1.33 +/- 0.3 cm to 0.92 +/- 0.25 cm (P less than 0.01) and posterior wall thickness from 1.03 +/- 0.23 cm to 0.93 +/- 0.23 cm (P less than 0.05). While the maximum changes in left ventricular mass were noted by the end of first month (P less than 0.01) with insignificant changes thereafter, the correlation of fall in blood pressure with change in left ventricular mass was significant only after 2 months of treatment (P less than 0.05). Indices of left ventricular function (end-diastolic volume, ejection fraction, fractional diameter shortening, left atrial dimension and posterior aortic wall motion) were normal before treatment and remained unchanged during 3 months of treatment. In this short-term study, labetalol reduced left ventricular hypertrophy (expressed as left ventricular mass and wall thickness) without altering left ventricular function indices in patients with uncomplicated essential hypertension. This has important implications in the treatment of hypertensive patients.