EFFECTIVENESS OF LONG-TERM BETA-BLOCKER THERAPY FOR DILATED CARDIOMYOPATHY - ECHOCARDIOGRAPHICAL FOLLOW-UP

To evaluate the effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy (DCM), two groups (Group I: 18 patients, Group II: 17 patients) with DCM divided by the order at the entry were followed echocardiographically for 16.9 +/- 3.0 months in Group I and 21.4 +/- 3.9 months in Group II. Metoprolol (final dose: 60 mg/day) was administered in Group I, but not in Group II (the control), although the conventional treatment for heart failure was continued. The left ventricular end-systolic dimension and ejection fraction assessed by echocardiography improved significantly after 6 months in Group I, but not in Group II, even after 48 months, although there were no significant differences in baseline data between the two groups. The enddiastolic dimension decreased significantly after 12 months in Group I only. It was estimated, using the point count method on a left ventricular endomyocardial biopsy specimen taken at entry, that the improvement (DELTA-EF) of the ejection fraction 12 months after metoprolol administration inversely correlated (r = -0.677, p < 0.01) with percent fibrosis, indicating that the more myocardium remains, the more improvement is expected. These findings suggested a favorable effect of beta blockade in DCM, especially in cases with less fibrosis, showing that the endomyocardial biopsy could be of clinical use in selecting candidates for chronic beta-blocker therapy in DCM.