Haemodynamic effects of pindolol in hypertensive patients

Five men and five women, mean age 48 years, with hypertension in stages I or II of the WHO classification, were given preoral treatment with pindolol. The pindolol treatment lead a significant decrease in the systolic and diastolic blood pressure, at rest and during work both after 2 months and after 16 months treatment. 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 venous capacitance affecting the venous return. Comparison of the results after 2 and after 16 months of treatment suggests that a decrease in cardiac output is an early mechanism in the lowering of the blood pressure, while a decrease in vascular resistance seems to be more important after long-term treatment with pindolol.