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

Abstract

Background: The effect of b-blockage on cardiac dyssynchrony in idiopathic dilated cardiomyopathy (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. © 2014 Via Medica.