Aim: The object of this study was to investigate and compare the haemodynamic effects of treatment with a beta receptor blocker (metoprolol) or an angiotensin-converting-enzyme inhibitor (captopril) in 54 patients with idiopathic dilated cardiomyopathy.
Method: All patients had cardiac catheterization performed at rest and during exercise, before and after 3 months of treatment.
Results: The mean dose of metoprolol was 135 mg.day-1 and of captopril 98 mg.day-1. After treatment there was a significant reduction in left ventricular filling pressure both at rest (from 16 to 12 mmHg) and during exercise (from 27 to 20 mmHg) in the metoprolol group. In the captopril group a significant reduction was seen only during exercise (25 to 20 mmHg), compared to baseline. The stroke volume increased significantly after 3 months of therapy in the metoprolol group, both at rest (53 to 70 ml) and during exercise (56 to 79 ml). In the captopril group the increase reached significance only during exercise (72 to 79 ml). Cardiac output was maintained in both groups.
Conclusion: There were positive effects on left ventricular function in the metoprolol group as well as in the captopril group. Metoprolol reduced left ventricular filling pressure at rest and increased stroke volume both at rest and during exercise significantly more than captopril.