Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT

OBJECTIVES The aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT. BACKGROUND MR is very frequent among patients with dilated cardiomyopathy and conduction delay. METHODS Echocardiograms (pre-CRT and 12 +/- 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area. RESULTS At baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (DLV end-systolic volume-35.5% +/- 27.2% vs-4.1% +/- 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction. CONCLUSIONS ApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR. (C) 2022 by the American College of Cardiology Foundation.

Automated summary

This study aimed to explore the association between mechanical dyssynchrony of the left ventricle before CRT and improvement of MR after CRT. The results showed that ApRock, SF, and baseline MR were strongly associated with MR reduction after CRT, with LV reverse remodeling being its underlying mechanism.