Beta-blockers in congestive cardiomyopathy. Conceptual advance or contraindication?

Beneficial effects of metoprolol in heart failure associated with coronary artery disease: a randomized trial

OBJECTIVES

This clinical trial was performed to determine the safety and clinical impact of titrated metoprolol therapy in patients with heart failure, documented coronary artery disease and a low ejection fraction.

BACKGROUND

Despite known cardiodepressant effects, long-term use of beta-adrenergic antagonists appears to be beneficial in patients with idiopathic dilated cardiomyopathy. However, this therapy has not been critically evaluated in patients with heart failure and coronary artery disease.

METHODS

In 50 patients with heart failure, known coronary artery disease and an ejection fraction < or = 0.40, we examined the impact of metoprolol therapy in a 6-month double-blind, placebo-controlled randomized trial, assessing the frequency of heart failure exacerbations and changes in symptoms (New York Heart Association functional class), ejection fraction and exercise duration. Placebo-treated patients who completed 6-month follow-up studies then underwent a trial with metoprolol therapy (crossover group).

RESULTS

Metoprolol was titrated to a mean maximal dose of 87 mg/day (range 25 to 100) without serious adverse reactions. During double-blind therapy, use of a beta-blocker was associated with a significant reduction in the number of hospital admissions (4% vs. 32%, p < 0.05), overall improved functional class (p = 0.02), increased ejection fraction (4 +/- 7% [mean +/- SD] compared with 0 +/- 6%, p < 0.05) and a greater increase in exercise duration (193 +/- 276 vs. 38 +/- 213 s with placebo, p < 0.01). Crossover outcome paralleled the favorable impact seen during randomized metoprolol therapy.

CONCLUSIONS

Cautious use of titrated metoprolol appears to be safe and beneficial when added to standard heart failure therapy in patients with dilated cardiomyopathy associated with coronary artery disease.

Chronic congestive heart failure. Where have we been? Where are we heading?

Chronic congestive heart failure is a frequently occurring disease associated with an impaired quality of life and significant mortality rate. Progress has been made in dissecting the pathophysiologic changes of congestive failure and in using vasodilators, newer positive inotropic agents, and other treatment modalities. Despite these advances, the overall mortality rate from congestive heart failure has not decreased. Further, many unanswered questions remain: How and why does a myocardial cell die? How should quality of life be measured? When should vasodilators and positive inotropic agents be given? What role do receptors play in pathogenesis and therapy? Can sudden death in heart failure be prevented? These and other questions will provide the stimulus for further studies in congestive heart failure.