β-blockers in heart failure : Do they improve the quality as well as the quantity of life?

Heart failure is a common clinical problem in patients with cardiovascular disease. Mortality remains high despite conventional therapy. The morbidity associated with heart failure accounts for numerous hospitalizations and significant health care expenditures. Therapy has been directed at relieving symptoms, augmenting exercise capacity, reducing hospitalizations and improving survival. Randomized clinical trials have shown that angiotensin-converting enzyme (ACE) inhibitors achieve these therapeutic goals and exert a favourable influence on disease progression. Recent clinical trials evaluating metoprolol, bisoprolol and carvedilol have clearly established that judicious use of beta-adrenergic blockers in heart failure patients who have been stabilized favourably influences the natural history of the disease, even when given as additional therapy to patients already receiving ACE inhibitors. Carvedilol is a non-selective beta-adrenergic blocking drug with vasodilatory properties that has been recently approved by the U.S. Food and Drug Administration for use in patients with NYHA functional class II or III heart failure. It was the only agent to produce a statistically significant survival benefit in a pre-specified analysis that included all the patients randomized into the multicentre U.S. Carvedilol Heart Failure Trials Program, irrespective of disease aetiology. As with trials looking at ACE inhibitor therapy, studies involving beta-blocker therapy in patients with heart failure have evaluated the effects of these drugs on hospitalization, NYHA functional class, exercise capacity and survival. In the U.S. Carvedilol Heart Failure Trials Program, the risk of hospitalization for any cause was reduced by 29%, the risk of hospitalization for a cardiovascular cause was reduced by 28% and the risk of dying was reduced by 65%. Thus, carvedilol has been shown in randomized clinical trials to improve the quantity of life and, at least in terms of the incidence of hospitalization, to improve the qualify of life as well. Randomized trials have consistently reported a favourable change in NYHA functional class in patients treated with beta-adrenergic blocking drugs: the majority of patients became less symptomatic. In the U.S. Carvedilol trials, patients and physicians reported (separately) an improvement in global status, and less deterioration when treatment was randomized to carvedilol. The positive influence of such therapy is reflected in a reduction in hos