[Haemodynamic response to antihypertensive treatment with atenolol in patients with hypertension (author's transl].

The antihypertensive effect of atenolol, a cardioselective beta-blocker, was examined in 8 patients with essential hypertension. The most important haemodynamic changes observed were a significant reduction in heart rate (reduction in maximum heart rate at the end of symptom-limited exercise by 23% p less than 0.01) and a moderate fall in systolic blood pressure (reduction at submaximum level of exercise by 22%, p less than 0.01). The antihypertensive effect was attributable in half the patients to a drop in peripheral vascular resistance and in the other half evenly to a predominant reduction in cardiac output or to a reduction in both parameters. In view of the compensatory rise in stroke volume a significant reduction in cardiac output was not found. Symptom-limited exercise tolerance was increased in all patients. These results lead to the conclusion that the antihypertensive action of the cardioselective beta-blocker, atenolol is based on a lowering of the increased peripheral vascular resistance and a reduction in cardiac output; the latter mechanism is predominantly found in patients with hyperkinetic features.