Changes in early and late diastolic filling patterns induced by long-term adrenergic beta-blockade in patients with idiopathic dilated cardiomyopathy.

BACKGROUND

beta-Blockers have been used in patients with idiopathic dilated cardiomyopathy to improve cardiac performance and theoretically would be beneficial to diastolic function. However, there are few reports on changes in diastolic function during chronic pharmacological treatment of congestive heart failure.

METHODS AND RESULTS

The present study was a substudy in the international Metoprolol in Dilated Cardiomyopathy Trial. Transmitral Doppler echocardiography was used to evaluate diastolic function in 77 patients randomly assigned to placebo (n = 37) or metoprolol (n = 40). The patients were treated for 12 months. Changes in Doppler flow variables in the metoprolol group implied a less restrictive filling pattern, expressed as an increase in E-wave deceleration time (placebo, 185 +/- 126 to 181 +/- 64 ms; metoprolol, 152 +/- 63 to 216 +/- 78 ms; P = .01, placebo versus metoprolol). Maximal increase in deceleration time had occurred by 3 months, whereas systolic recovery was achieved gradually and maximal effect was seen by 12 months of treatment. Although deceleration time was correlated to heart rate at baseline, changes in deceleration time were not significantly correlated to changes in heart rate during treatment.

CONCLUSIONS

During the first 3 months of treatment, maximal effects on diastolic variables were reached, whereas the most prominent effect on systolic function was seen late in the study. It is suggested that effects on diastolic filling account for subsequent later myocardial systolic recovery. The E-wave deceleration time, which in recent studies has been shown to be a powerful predictor of survival, was significantly improved in the metoprolol-treated patients.