Beta-blockade in heart failure : comparison of carvedilol with metoprolol

OBJECTIVES This study was performed to compare the long-term clinical efficacy of treatment with metoprolol versus carvedilol in patients with chronic heart failure. BACKGROUND Beta-adrenergic blockade is of proven value in chronic heart failure. Metoprolol, selective beta-blocker, is widely used, but recent trials suggest carvedilol, nonselective beta-blocker with alpha-1-receptor antagonist activity and antioxidant activities, is also effective. It is uncertain, however, if these additional properties of carvedilol provide further clinical benefit compared with metoprolol. METHODS In this randomized double-blind control trial, 51 patients with chronic heart failure and mean left ventricular (LV) ejection fraction of 26% ± 1.8% were randomly assigned treatment with metoprolol 50 mg twice daily or carvedilol 25 mg twice daily in addition to standard therapy after four-week dose titration period for total of 12 weeks. Response was assessed by quality of life questionnaire, New York Heart Association class, exercise capacity (6-min walk test), radionucleotide ventriculography for LV ejection fraction, two-dimensional echocardiography measurement of LV dimensions and diastolic filling and 24-h electrocardiograph monitoring to assess heart rate variability. RESULTS Both carvedilol and metoprolol produced highly significant improvement in symptoms (p < 0.001), exercise capacity (p < 0.05) and LV ejection fraction (p < 0.001), and there were no significant differences between the two drugs. Carvedilol had significantly greater effect on sitting and standing blood pressure, LV end-diastolic dimension and normalized the mitral E wave deceleration time. CONCLUSIONS Both metoprolol and carvedilol were equally effective in improving symptoms, quality of life, exercise capacity and LV ejection fraction, although carvedilol lowers blood pressure more than metoprolol.