Differential Effects of β-Blockers in Patients With Heart Failure

Abstract

Background —Both metoprolol and carvedilol produce hemodynamic and clinical benefits in patients with chronic heart failure; carvedilol exerts greater antiadrenergic effects than metoprolol, but it is unknown whether this pharmacological difference results in hemodynamic and clinical differences between the 2 drugs. Methods and Results —We randomized 150 patients with heart failure (left ventricular ejection fraction ≤0.35) to double-blind treatment with either metoprolol or carvedilol. When compared with metoprolol (124±55 mg/d), patients treated with carvedilol (49±18 mg/d) showed larger increases in left ventricular ejection fraction at rest (+10.9±11.0 versus +7.2±7.7 U, P =0.038) and in left ventricular stroke volume and stroke work during exercise (both P P P =0.035), but the 2 drugs improved symptoms, submaximal exercise tolerance, and quality of life to a similar degree. After a mean of 23±11 months of follow-up, 21 patients in the metoprolol group and 17 patients in the carvedilol group died or underwent urgent transplantation. Conclusions —The present study demonstrates that during long-term therapy, carvedilol improves cardiac performance to a greater extent than metoprolol when administered to patients with heart failure in the doses shown to be effective in clinical trials. These differences were likely related to a greater antiadrenergic activity of carvedilol.