Evaluation of beta-blockers on left ventricular dyssynchrony and reverse remodeling in idiopathic dilated cardiomyopathy: A randomized trial of carvedilol and metoprolol.

BACKGROUND The effect of b-blockage on cardiac dyssynchrony in idiopathic dilated cardio-myopathy (IDC) is unknown. This study evaluated the impact of carvedilol and metoprolol succinate on left ventricular (LV) dyssynchrony and reverse remodeling in IDC. METHODS In this small, prospective, double-blind study, we randomly assigned 81 IDC patients to receive carvedilol or metoprolol succinate. Echocardiographic measurements (dyssynchrony, LV volumes and ejection fraction [EF]) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were obtained at baseline and at first and sixth month of therapy. RESULTS A total of 74 (91%) patients completed all investigations at sixth month (38 and 36 taking carvedilol and metoprolol succinate, respectively). In the carvedilol group, reduction in LV end diastolic volume (D LVEDV at 6 months, 50 ± 15 mL to 40 ± 17 mL, p = 0.03) and increase in LVEF (D LVEF, 7 ± 2% to 5 ± 3%, p = 0.02) was higher compared to the metoprolol group. Also improvement in inter-ventricular dyssynchrony achieved with carvedilol was higher than metoprolol (D interventricular delay at 6 months, 11 ± 8 ms to 6 ± 7 ms, p = 0.03). However, improvement in intraventricular dyssynchrony was similar in the two groups (D intraventricular delay, 9 ± 7 ms to 9 ± 6 ms, p = 0.91). Improvements in LV mechanical dyssynchrony and reverse remodeling achieved with both drugs were accompanied by reduction in NT-proBNP levels in both carvedilol and metoprolol groups (1614 ± 685 pg/mL to 654 ± ± 488 pg/mL and 1686 ± 730 pg/mL to 583 ± 396 pg/mL, respectively, p < 0.001 for both). CONCLUSIONS Although reduction in LVEDV and increase in LVEF was higher with carvedilol, improvement in intraventricular dyssynchrony was similar in carvedilol and metoprolol groups.