Selective or nonselective beta-adrenergic blockade in patients with congestive heart failure

Abstract

Controlled clinical trials, performed in more than 13,000 patients, have consistently shown the beneficial effects of long-term beta-blocker therapy in patients with chronic heart failure. However, it is not clear whether this is a class effect or if it is specific only for some agents. Beneficial effects on the prognosis of the patients with mild to moderate heart failure have been obtained with metoprolol, bisoprolol, and carvedilol. Metoprolol and bisoprolol are selective for beta(1)-receptors and without ancillary properties, carvedilol, at doses of 25 mg twice daily, blocks beta(1)-, beta(2)-, and a(1)-adrenergic receptors, and has associated antiproliferative and antioxidant activities. These differences are important for the acute hemodynamic effects, but it is still controversial whether they may also influence the long-term effects of therapy. Differently from selective b-blockers, carvedilol blocks all adrenergic receptors, does not upregulate beta1-receptors, decreases cardiac norepinephrine release, and has associated antioxidant effects. These differences may cause a larger increase in left ventricular function, which was significant in some, but not all of the direct comparisons of the two agents. The long-term effects of different beta-blockers on prognosis are currently compared in the Carvedilol or Metoprolol European Trial, in which more than 3000 patients with chronic heart failure have been 1:1 randomized to metoprolol or carvedilol and are going to be followed for more than 2 years.