Hemodynamic effect of long--term treatment with pindolol in essential hypertension with special reference to the resistance and capacitance vessels of the forearm.

Ten patients with essential hypertension have been studied at rest, during and after exercise following oral treatment for on an average 16 months with a beta-adrenoreceptor blocking agent, pindolol. The study was a direct continuation of an earlier, performed after 2 months' treatment. The hypotensive effect of pindolol was highly significant after 2 as well as 16 months of treatment. Heart rate was similarly lowered at 2 and 16 months, while carciac output, which was significantly lower during exercise after 2 months, had increased to the pretreatment level after 16 months. Peripheral vascular resistance, which was not affected after 2 months, had decreased significantly during and after exercise in the long-term study. A comparison between the hemodynamic situations after 2 and 16 months thus suggests that while a decrease in cardiac output is an early mechanism in the lowering of BP, changes in systemic vascular resistance seem to be more important after long-term treatment with pindolol.