Left ventricular hypertrophy reversal with labetalol and propranolol: a prospective randomized, double-blind study

Abstract

Hypertensive patients with left ventricular hypertrophy (LVH) have increased cardiovascular morbidity and mortality. Experimental studies indicate the importance of both the alpha and beta components of the adrenergic nervous system in the development and reversal of LVH. Therefore labetalol (L), a combined alpha and beta blocker, and propranolol (P), a nonselective beta blocker, were evaluated in a randomized, double-blind study of 35 hypertensive patients with echocardiographic evidence of LVH. Following 2 weeks of placebo, L or P was titrated as needed and tolerated to maximum total daily doses of 1600 mg and 640 mg, respectively. A thiazide diuretic was added if necessary for blood pressure control. M-mode echocardiograms were performed at baseline and after 1, 3, 6, and 12 months of blood pressure control. The echocardiograms were read independently by two blinded observers for end-diastolic dimension and wall thicknesses, and left ventricular mass. Fractional shortening, cardiac output, and peripheral vascular resistance were derived using standard formulas. Both drugs reduced blood pressure significantly and comparably. Significant changes in the echocardiographic measurements were observed as early as 1 month and usually persisted throughout the study. Both drugs decreased posterior wall thickness; however, only the decrease in propranolol group achieved statistical significance. Septal wall thickness was reduced by L at 3 and 12 months. End-diastolic dimension increased significantly in the L-treated group at 3, 6, and 12 months of therapy, whereas P had no effect on this measurement.(ABSTRACT TRUNCATED AT 250 WORDS)