More than 25 years ago it was proposed that beta blockers may be of benefit in heart failure1 and yet, until recently, there has been a general reluctance amongst the medical profession to prescribe them for this indication. This is not entirely surprising, as not too long ago heart failure was widely considered to be a major contraindication for the use of beta blockers. There is now considerable evidence from major clinical trials that beta blockers are capable of improving both the symptoms and prognosis of
patients with congestive heart failure (CHF).

The results from the second Cardiac Insufficiency Bisoprolol Study (CIBIS-II) and the Metoprolol CR/XL Randomised Intervention Trial in Heart Failure (MERIT-HF) have shown that selective 1 antagonists (i.e. bisoprolol and metoprolol respectively) can improve survival in patients with CHF.2,3 Carvedilol, a relatively new agent, is a non-selective beta blocker, which also has antioxidant effects and causes vasodilatation. A multi-centre US study showed there to be a 65% mortality reduction with carvedilol as compared with placebo.4 At present it is not clear whether 1 selectivity is important with respect to therapy in CHF, and this question is currently being addressed in the Carvedilol and Metoprolol European Trial (COMET).

In the UK, carvedilol has been licensed for the treatment of mild to moderate CHF (NYHA class II or III) and bisoprolol is also likely to be approved in the near future. Prior to commencement with beta blockers, patients should be clinically stable and maintained on standard therapy with diuretics, ACE inhibitors +/– digoxin. There is insufficient evidence at present to recommend the treatment of unstable or NYHA class IV patients. The Carvedilol Prospective Randomised Cumulative Survival Trial (COPERNICUS), which is recruiting patients with severe CHF, (NYHA class IIIB-IV) will hopefully be able to answer this question in the future.

Treatment should be initiated at a low dose and be increased gradually under supervised care. The patient should be monitored for 2–3 hours after the initial dose and after each subsequent dose increase to ensure that there is no deterioration in symptoms, significant bradycardia, or hypotension. In patients with suspected or known renal impairment, it is recommended that serum biochemistry is also monitored. A suggested protocol is as follows: initiate carvedilol at 3.125mg twice daily; the dose may be doubled at intervals of two weeks to a maximum of 25mg twice daily, depending upon tolerance.

It is clear that beta blockers are of prognostic benefit in patients with stable CHF who are in NYHA class II to III. However, there are several important areas in which the effect of beta blocker therapy is unknown. For example, should we be using beta blockers to treat asymptomatic patients with evidence of systolic ventricular dysfunction and is there a role for beta blocker therapy in the patient post-myocardial infarction who has ventricular impairment? Clinical trials are currently being performed to answer these questions.

Evidence of a beneficial effect of beta blockers on the syndrome of heart failure is accumulating. The use of beta blockers in this context may prove to be one of the most important pharmacological “re-discoveries” in cardiology in recent years.

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