Haemodynamic effects in man during exercise of a single oral dose of narbivolol (R 67555), a new beta‐1‐adrenoceptor blocking agent: A comparative study with atenolol, pindolol, and propranolol

In eight normal volunteers R 67555 at 5 mg and 10 mg significantly lowered the exercise‐induced increase of systolic blood pressure by 20 and 25%, and the exercise‐induced increase of heart rate by 20 and 21% respectively. The blood pressure lowering effect of R 67555 6 hr after intake was comparable to that observed after atenolol, pindolol, and propranolol. In contrast, the lowering of exercise‐induced increase of heart rate was significantly less with R 67555 than with the other beta‐blockers tested. The ratio of PEP c /LVET c , a measure of left ventricular performance, significantly increased 3 hr after intake aof atenolol, propranolol, and 10 mg of R 67555 but not after pindolol and 5 mg of R 67555. Six hr after administration of pindolol and of 5 mg of R 67555, the ratio PEP C /LVET c was significantly lowered as compared with control values. The post‐exercise left ventricular ejection time (LVET c ) significantly shortened 3 hr and 6 hr after intake of 5 mg and 10 mg of R 67555, whereas a trend to prolongation was observed after administration of atenolol, pindolol, and propranolol.