Metoprolol therapy improved ventricular function between months 1 and 3 (p=0.013) and reduced left ventricular mass from 333 to 275 g by 18 months (p=0.011).
RCT (n=26)
Blinded outcome assessment
Does metoprolol improve ventricular function, mass, and geometry over time in men with dilated cardiomyopathy?
Metoprolol therapy in heart failure initially causes a mild reduction in systolic function, followed by improvement after 1 month and long-term reversal of maladaptive remodeling by 18 months.
p-value: p=0.013
OBJECTIVES: We examined the time course of ventricular functional improvement in patients with dilated cardiomyopathy who received beta-blockade and the long-term effects of beta-blockade on ventricular mass and geometry in these patients. BACKGROUND: Previous studies have shown that beta-adrenergic blocking agents when administered long term improve ventricular function in patients with heart failure. However, the time course of improvement in ventricular function and the long-term effects of beta-blockade on ventricular mass and geometry are not known. METHODS: Twenty-six men with dilated cardiomyopathy underwent serial echocardiography on days 0 and 1 and months 1 and 3 of either metoprolol (n = 16) or standard therapy (n = 10). At 3 months all patients on standard therapy were crossed over to metoprolol, and late echocardiograms were obtained after 18 +/- 5 (mean +/- SD) months of metoprolol therapy. All echocardiograms were read in blinded manner. RESULTS: Patients treated with metoprolol had an initial decline (day 1 vs. day 0) in ventricular function (increase in end-systolic volume and decrease in ejection fraction). Ventricular function improved between months 1 and 3 (p = 0.013, metoprolol vs. standard therapy). Left ventricular mass regressed at 18 months (333 +/- 85 to 275 +/- 53 g, p = 0.011) but not at 3 months. Left ventricular shape became less spherical and assumed a more normal elliptical shape by 18 months (major/minor axis ratio 1.5 +/- 0.2 to 1.7 +/- 0.2, p = 0.0001). CONCLUSIONS: Patients with heart failure treated with metoprolol do not demonstrate an improvement in systolic performance until after 1 month of therapy and may have a mild reduction in function initially. Long-term therapy with metoprolol results in a reversal of maladaptive remodeling with reduction in left ventricular volumes, regression of left ventricular mass and improved ventricular geometry by 18 months.
Hall et al. (1995) conducted an RCT in Dilated cardiomyopathy (n=26). Metoprolol vs. Standard therapy was evaluated on Ventricular function improvement between months 1 and 3 (p=0.013). Metoprolol therapy improved ventricular function between months 1 and 3 (p=0.013) and reduced left ventricular mass from 333 to 275 g by 18 months (p=0.011).