1. We compared the effects, after 3 weeks oral
therapy, of
xamoterol 200 mg twice daily and
enalapril 2.5, 5 or 10 mg twice daily on home and clinic blood pressure, glomerular filtration rate (GFR) and renal plasma flow,
stroke and minute distances, linear resistance and on plasma
renin activity in 19 patients with mild to moderate
heart failure in a single-blind randomised crossover study. 2.
Enalapril reduced mean home blood pressure by 17/7 mm Hg compared with
xamoterol (P less than 0.0001) and by 19/7 mm Hg compared with placebo. Compared with placebo
xamoterol had no effect.
Enalapril reduced predose blood pressure, compared with
xamoterol, on average by 15/5 mm Hg (P = 0.02 systolic, 0.09 diastolic) and by 20/7 mm Hg compared with placebo. At 4 h post-dose the mean differences were:
xamoterol-
enalapril 13/10 mm Hg (P = 0.01 systolic, 0.0007 diastolic) and placebo-
enalapril 23/9 mm Hg. 3.
Stroke and minute distances were marginally less 4 h following
xamoterol than following
enalapril: mean (s.e. mean) values were 9.4 (0.7) vs 10.4 (0.8) cm (P = 0.23) and 699 (51.7) vs 767 (62.1) cm (P = 0.04) respectively. Linear resistance was reduced by
enalapril, from the placebo value of 13.2 (1.2) to 11.0 (0.9) mm Hg m-1 and marginally increased by
xamoterol, to 14.2 (1.2) mm Hg m-1, the difference between active treatments being statistically significant (P = 0.03). 4. Renal plasma flow, GFR and filtration fraction were not influenced by
enalapril or
xamoterol therapy. There were no significant correlations between glomerular filtration rate and either blood pressure or
stroke distance.(ABSTRACT TRUNCATED AT 250 WORDS)