Metoprolol Reverses Left Ventricular Remodeling in Patients With Asymptomatic Systolic Dysfunction

Abstract

Background— There are no randomized, controlled trial data to support the benefit of β-blockers in patients with asymptomatic left ventricular systolic dysfunction. We investigated whether β-blocker therapy ameliorates left ventricular remodeling in asymptomatic patients with left ventricular systolic dysfunction. Method and Results— Patients with left ventricular ejection fraction <40%, mild left ventricular dilation, and no symptoms of heart failure (New York Heart Association class I) were randomly assigned to receive extended-release metoprolol succinate (Toprol-XL, AstraZeneca) 200 mg or 50 mg or placebo for 12 months. Echocardiographic assessments of left ventricular end-systolic volume, end-diastolic volume, mass, and ejection fraction were performed at baseline and at 6 and 12 months. The 149 patients randomized to the 3 treatment groups (200 mg, n=48; 50 mg, n=48; and placebo, n=53) were similar with regard to all baseline characteristics including age (mean, 66 years), gender (74% male), plasma brain natriuretic peptide (79 pg/mL), left ventricular end-diastolic volume index (110 mL/m 2 ), and left ventricular ejection fraction (27%). At 12 months in the 200-mg group, there was a 14±3 mL/m 2 decrease (least square mean±SE) in end-systolic volume index and a 6±1% increase in left ventricular ejection fraction ( P <0.05 versus baseline and placebo for both). The decrease in end-diastolic volume index (14±3) was different from that seen at baseline ( P <0.05) but not with placebo. In the 50-mg group, end-systolic and end-diastolic volume indexes decreased relative to baseline but were not different from what was seen with placebo, whereas ejection fraction increased by 4±1% ( P <0.05 versus baseline and placebo). Conclusion— β-Blocker therapy can ameliorate left ventricular remodeling in asymptomatic patients with left ventricular systolic dysfunction.