Role of beta blockers in heart failure

Role of beta blockers in heart failure

Traditionally it is thought that sympatho-adrenergic system activation is compensatory in heart failure. This is true in acute heart failure. But in chronic heart failure, sympatho-adrenergic system becomes counterproductive and maladaptive. It increases the afterload and myocardial cell necrosis as well down regulation of beta receptors. This is why beta blockers have been considered in the treatment of chronic heart failure. Studies have shown that if you treat 100 patients with heart failure, it will prevent 4 deaths and 4 hospitalisations. Carvedilol, bisoprolol and metoprolol succinate have been shown to improve the survival in heart failure in various studies, but bucindolol failed to do so in the BEST trial [1]. Even though COMET trial [2] showed superiority of carvedilol over metoprolol tartrate, there were several criticisms about the methodology of the trial questioning whether it was a fair comparison. Metoprolol tartrate was a short acting preparation compared to the metoprolol succinate extended release preparation which was shown to be useful in heart failure earlier. Hence the superiority of carvedilol over metoprolol in heart failure is not yet fully accepted. Beta blockers are indicated in all patients with symptomatic heart failure. But they have to be started only only when they are stable and not on inotropic support or intravenous diuretics.

References

1. Beta-Blocker Evaluation of Survival Trial Investigators; Eric J Eichhorn, Michael J Domanski, Heidi Krause-Steinrauf, Michael R Bristow, Philip W Lavori. A trial of the beta-blocker bucindolol in patients with advanced chronic heart failure. N Engl J Med. 2001 May 31;344(22):1659-67.
2. Philip A Poole-Wilson, Karl Swedberg, John G F Cleland, Andrea Di Lenarda, Peter Hanrath, Michel Komajda, Jacobus Lubsen, Beatrix Lutiger, Marco Metra, Willem J Remme, Christian Torp-Pedersen, Armin Scherhag, Allan Skene, Carvedilol Or Metoprolol European Trial Investigators. Comparison of carvedilol and metoprolol on clinical outcomes in patients with chronic heart failure in the Carvedilol Or Metoprolol European Trial (COMET): randomised controlled trial. Lancet. 2003 Jul 5;362(9377):7-13.