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MIC trial: metoprolol in patients with mild to moderate heart failure: effects on ventricular function and
S Genth-Zotz1, R J Zotz, M Sigmund
1Department of Medicine II, Johannes Gutenberg-University, Langenbeckstrasse 1, 55131, Mainz, Germany.
Insights
Metoprolol improves heart function and exercise capacity in patients with heart failure (CHF). This beta-blocker therapy benefits both dilated cardiomyopathy (DCM) and coronary artery disease (CAD) patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Beta-blocker therapy is known to benefit heart failure (CHF) patients with idiopathic dilated cardiomyopathy (DCM).
- The efficacy of beta-blockers in CHF patients with ischemic heart disease (CAD) requires further investigation.
Purpose of the Study:
- To assess the functional benefits of metoprolol in patients with CHF secondary to CAD.
- To compare the effects of metoprolol in patients with DCM and CAD.
Main Methods:
- A placebo-controlled study involving 52 patients with CHF (26 DCM, 26 CAD) and left ventricular ejection fraction (EF) <40%.
- Metoprolol dosage was titrated to a mean final dose of 135 mg/day over 6 weeks.
- Cardiac function, cardiopulmonary exercise capacity (Vo(2)-max, Vo(2)-AT), and 6-minute walk test were assessed.
Main Results:
- Metoprolol significantly reduced heart rate at rest and during exercise.
- Significant improvements were observed in Vo(2)-max, Vo(2)-AT, and the 6-minute walk test.
- Left ventricular ejection fraction (EF) significantly increased in metoprolol-treated patients (from 27.3% to 35.2% at rest).
- Reduced left ventricular volumes were noted.
- No significant differences in response were found between CAD and DCM patient groups.
Conclusions:
- Additional therapy with metoprolol improved cardiac function and cardiopulmonary exercise capacity in patients with CHF.
- Metoprolol demonstrated functional benefits in CHF patients regardless of underlying etiology (DCM or CAD).
Unlabelled:
Beta-blocker therapy results in a functional benefit in patients with heart failure (CHF) due to idiopathic dilated cardiomyopathy (DCM). This study assessed if similar effects were observed in patients with ischemic heart disease (CAD), NYHA II-III after 6 months of therapy with metoprolol.
Methods And Results:
Fifty-two patients with CHF secondary to DCM (26 patients) and CAD (26 patients) and a left ventricular ejection fraction (EF)<40% were enrolled in the placebo-controlled study. The study medication was titrated over 6 weeks, the mean final dosage was 135 mg/day. Three patients died due to cardiogenic shock, two received placebo and one metoprolol. Eight patients did not complete the study due to non-compliance. Metoprolol significantly reduced heart rate at rest and after submaximal and maximal exercise. Vo(2)-max and Vo(2)-AT as well as the 6-min walk test improved significantly after metoprolol treatment. There was a significant increase in EF at rest (27.3-35. 2%), submaximal (28.5-37.7%) and maximal exercise (28.7-40.9%) in the metoprolol-treated patients. No differences were found between patients with CAD and DCM. We also observed reduced left ventricular volumes.
Conclusion:
The additional therapy with metoprolol improved cardiac function and the cardiopulmonary exercise capacity in patients with CHF.