Effects of beta-blockers on neurohormonal activation in patients with congestive heart failure.

The effect of beta-adrenoceptor antagonists (beta-blockers) on neurohormonal activation in patients with congestive heart failure has been the subject of study in numerous small clinical trials. Short term therapy with beta-blockers is associated with a variable acute neurohormonal response which may be determined by the pharmacology of the agent under study and the baseline characteristics of the patient population. Long term therapy with beta-blockers devoid of intrinsic sympathomimetic activity (partial agonist activity) is associated with evidence of decreased plasma markers of activation of the sympathetic nervous system, the renin-angiotensin system, and endothelin-1. Beta1-selective and nonselective beta-blockers appear to be associated with evidence of decreased neurohormonal activation, with differential effects on beta-adrenoceptor density. Agents with partial agonist activity appear to differ from pure antagonists, with some studies reporting evidence of increased neurohormonal activation. The mechanisms by which beta-blockers reduce neurohormonal activation and the clinical relevance of changes in adrenergic function to their use in the treatment of heart failure require further investigation.