Does beta 1-selective agonistic activity interfere with the antihypertensive efficacy of beta 1-selective blocking agents?

In order to investigate whether addition of beta 1-selective agonism can interfere with the antihypertensive efficacy of beta 1-selective adrenoceptor blockers, two separate studies were carried out to evaluate the effects on blood pressure and heart rate of three beta 1-selective blockers with or without varying degree of beta 1-selective agonism. In hypertensive patients at rest, the greatest blood pressure reduction and bradycardia were found with atenolol, a beta 1-selective blocker without any agonistic activity; a consistently smaller effect on blood pressure and heart rate was observed with Visacor (ICI 141 292), a beta 1-selective blocker with moderate beta 1-selective agonism, whereas no clinically relevant decrease in blood pressure occurred with Corwin (ICI 118 587), the beta 1-selective blocker with high beta 1-selective agonism. In contrast, during exercise-induced sympathetic activation, all three compounds reduced systolic blood pressure and heart rate to a similar degree.