Hemodynamic Effect of Pindolol in Essential Hypertension with Special Reference to the Resistance and Capacitance Vessels of the Forearm

Ten patients, mean age 48 years, with essential hypertension of stage I and II according to the WHO classification, have been studied at rest and during work before and after on average 8 weeks oral treatment with a beta-adrenergic blocking agent, pindolol. The pindolol treatment caused a significant decrease in the systemic systolic and diastolic blood pressure, heart rate and cardiac output both at rest and during work. The systemic vascular resistance and the forearm vascular resistance decreased significantly after and during work, respectively. Forearm venous tone was significantly decreased at rest, during and after work. The plasma renin activity decreased. Three mechanisms seem to be involved in the antihypertensive effect of pindolol: 1) a negative chronotropic effect on the heart, 2) a decrease in peripheral vascular resistance, and 3) an increase in vascular capacitance affecting the venous return.