The impact of beta-blockade on right ventricular function in mitral regurgitation.

BACKGROUND: Although mitral regurgitation (MR) results in left ventricular (LV) volume overload, right ventricular (RV) function may also be impaired. We investigated the influence of short-term beta-blockade on RV function in patients with moderate-severe MR. METHODS: Twenty-six patients were randomised in a cross-over design to receive two weeks of beta-blockade or placebo. Echocardiography was performed at baseline and at the end of the treatment periods. Measurements included: RV ejection fraction (RVEF) tricuspid annular motion and Tei index. RESULTS: No differences in mean RVEF (64.0 ± 6.0 v 67.0 ± 8.0%, p=0.3), tricuspid annular motion (13.5 ± 3.0 v 14.7 ± 2.9 cm/s, p=0.5), or median Tei index (0.61 (0.54, 0.88) v 0.59 (0.54, 0.74), p=0.8) were observed between placebo and metoprolol, despite significantly longer cardiac time intervals. Tei index under both conditions was significantly reduced. CONCLUSIONS: Short-term treatment with a beta-blocker did not influence RV function in these patients. Interestingly, the RV Tei index was high suggesting significant RV dysfunction despite normal RVEF.