Repercussion of functional mitral regurgitation on reverse remodelling in cardiac resynchronization therapy

Abstract

Aims: Cardiac resynchronization therapy (CRT) reduces the degree of functional mitral regurgitation (FMR). However, FMR has also been associated with a lack of clinical response to CRT. We undertook this study to determine whether the presence of FMR influences the reverse remodelling induced by CRT. Methods and results: We used Doppler echocardiography to assess 20 patients with dilated cardiomyopathy before and 6 months after undergoing CRT. We evaluated the effect of reverse remodelling (reduction ≥ 10% in end-systolic volume) according to the presence or absence of important FMR, defined as a regurgitant orifice area (ROA) of ≥ 0.20 cm2. Of the 20 patients (mean age, 64.7 ± 8.2 years, eight women), 9 had marked FMR (ROA 0.40 ± 0.12 cm2), 6 mild FMR (ROA 0.15 ± 0.02 cm2), and 5 had trivial or no FMR. CRT reduced the presence of mitral regurgitation by 33.3% and induced reverse remodelling in 60% of the patients. A ROA ≥ 0.20 cm2 was associated with a lack of reverse remodelling, despite presenting similar baseline characteristics and a reduction in asynchrony to the other patients. Reverse remodelling was produced in all the other patients, with a significant reduction in end-systolic volume (41.7 ± 21% P = 0.003), accompanied by improvement in the ejection fraction (P = 0.003) and myocardial performance index (P = 0.027). Conclusion: CRT improved FMR, although the baseline presence of important mitral regurgitation, with a ROA ≥ 0.20 cm2, in patients undergoing CRT was associated with a lack of response in reverse remodelling. © The European Society of Cardiology 2007. All rights reserved.