Hemodynamics and plasma renin activity were measured in 20 ambulatory hospital inpatients with untreated mild to moderate essential hypertension. The control measurements were made after a period of four to seven days just on a diet containing 10 mEq sodium per day. The measurements were repeated following a week of oral propranolol hydrochloride therapy plus the low salt diet. Heart rate (P <.001), mean arterial pressure (P <.001), cardiac output (P <.05), and plasma renin activity (P <.05) were reduced in the majority of these patients following propranolol therapy but stroke volume increased (P <.05). Corrected ejection time and total peripheral resistance did not show significant change. The antihypertensive effect of propranolol could not be related to its hyporeninemic effect or to the fall in cardiac output. Under the experimental conditions of this study, no single parameter, either hemodynamic or plasma renin activity, was predictive of a definite antihypertensive response to propranolol therapy.
(Arch Intern Med 137:290-295, 1977)