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Effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy--echocardiographical follow-up
M Fukunami1, K Hashimura, M Ohmori
1Division of Cardiology, Osaka Prefectural Hospital, Japan.
Insights
Long-term beta-blocker therapy, specifically metoprolol, significantly improved heart function in patients with dilated cardiomyopathy (DCM). Less myocardial fibrosis predicted greater ejection fraction improvement, suggesting biopsy use for treatment selection.
Area of Science:
- Cardiology
- Pharmacology
- Internal Medicine
Background:
- Dilated cardiomyopathy (DCM) is a progressive condition affecting heart muscle function.
- Long-term therapeutic strategies for DCM require ongoing evaluation.
- Beta-blocker therapy is a potential treatment avenue for improving cardiac outcomes.
Purpose of the Study:
- To assess the long-term efficacy of beta-blocker therapy in patients with DCM.
- To determine if metoprolol improves echocardiographic parameters in DCM.
- To explore the relationship between myocardial fibrosis and treatment response.
Main Methods:
- A prospective study involving two groups of DCM patients (Group I: metoprolol treatment, Group II: control).
- Echocardiographic follow-up for evaluating left ventricular dimensions and ejection fraction.
- Analysis of endomyocardial biopsy specimens to quantify myocardial fibrosis.
Main Results:
- Metoprolol significantly improved left ventricular end-systolic dimension and ejection fraction in Group I compared to controls.
- Significant decrease in end-diastolic dimension observed in the metoprolol group after 12 months.
- Inverse correlation found between baseline myocardial fibrosis percentage and ejection fraction improvement (r = -0.677, p < 0.01).
Conclusions:
- Long-term metoprolol therapy demonstrates a favorable effect on cardiac function in DCM patients.
- Patients with less myocardial fibrosis may experience greater benefits from beta-blocker treatment.
- Endomyocardial biopsy can aid in selecting DCM patients suitable for chronic beta-blocker therapy.
Abstract:
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 end-diastolic 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 less than 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.