Effects of metoprolol CR in patients with ischemic and dilated cardiomyopathy : the randomized evaluation of strategies for left ventricular dysfunction pilot study.

BACKGROUND

Metoprolol provides clinical benefits in patients with congestive heart failure (CHF). In this study, we investigated the effects of controlled-release metoprolol (metoprolol CR) on clinical status, on left ventricular (LV) volumes and function, and on neurohumoral activation in a large number of patients with CHF of mixed causes.

METHODS AND RESULTS

Four hundred twenty-six patients with symptomatic CHF were randomized to receive metoprolol CR or placebo for 24 weeks. Metoprolol CR did not affect 6-minute walk distance, New York Heart Association functional class, or quality of life. However, there was a significant improvement in measures of LV function with an attenuation in the increase in LV end-diastolic (+23+/-65 mL [placebo] versus +6+/-61 mL, P=0.01) and LV end-systolic (+19+/-55 mL [placebo] versus -2+/-51 mL, P<0.001) volumes after 24 weeks of therapy. LV ejection fraction was unchanged (-0.05% or -0.005) in the placebo group but increased by 2. 4% in the metoprolol CR-treated patients (P=0.001). Patients receiving metoprolol CR had a greater decrease in angiotensin II (P=0.036) and renin (P=0.032) levels but an increase in N-terminal atrial natriuretic peptide and brain natriuretic peptide levels (P<0. 01). There were fewer deaths in the group receiving beta-blockers (3. 4% versus 8.1%), and there was a similar number of patients experiencing the composite outcomes of death or any hospitalization.

CONCLUSIONS

When added to ACE inhibitors, angiotensin II receptor antagonists, or both, the use of metoprolol CR improves ventricular function, reduces activation of the renin-angiotensin systems, and results in fewer deaths.