MIC trial: metoprolol in patients with mild to moderate heart failure: effects on ventricular function and cardiopulmonary exercise testing

Beta-blocker therapy results in a functional benefit in patients with heart failure (CHF) due to idiopathic dilated cardiomyopathy (DCM). This study a ssessed if similar effects were observed in patients with ischemic heart di sease (CAD), NYHA II-III after 6 months of therapy with metoprolol. Methods and results: Fifty-two patients with CHF secondary to DCM (26 patients) an d CAD (26 patients) and a left ventricular ejection fraction (EF) < 40% wer e enrolled in the placebo-controlled study. The study medication was titrat ed 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 pa tients did not complete the study due to non-compliance. Metoprolol signifi cantly reduced heart rate at rest and after submaximal and maximal exercise . (V) over dot O-2-max and (V) over dot O-2-AT as well as the 6-min walk te st improved significantly after metoprolol treatment. There was a significa nt 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 w ere found between patients with CAD and DCM. We also observed reduced left ventricular volumes. Conclusion: The additional therapy with metoprolol imp roved cardiac function and the cardiopulmonary exercise capacity in patient s with CHF. (C) 2000 European Society of Cardiology. All rights reserved.