Role of Left Atrial Reservoir Strain Rate in Left Atrial Remodeling in Severe Mitral Regurgitation

BACKGROUND: Impaired left atrial (LA) reservoir deformation has been found to be associated with poor functional capacity and outcomes in severe chronic mitral regurgitation (MR). Among patients with primary MR (valve incompetence due to mitral valve pathology), we focus on Carpentier II classification (prolapse or flail mitral valve) and aim to investigate determinants for decreased LA reservoir deformation and its impact on LA remodeling in severe MR. METHODS: Among 159 consecutive patients with severe chronic Carpentier II MR (left ventricular ejection fraction ≥ 60%), 55 underwent follow-up echocardiography, which was compared with their baseline study. We used the change of LA volume index as the rapidity of LA remodeling, LA eccentricity index as LA sphericity, and peak LA reservoir strain as well as reservoir strain rate (LASR(R)) derived from two-dimensional speckle-tracking echocardiography as LA reservoir function. RESULTS: Older age, elongated left atrium, increased LA volume index, as well as reduced left ventricular global longitudinal strain and LA ejection fraction all linked to a poor baseline LASR(R) (all p < 0.001). A second echocardiography during a mean follow-up of 15.3 ± 8.3 months revealed an enlarged left atrium (increased interval change of LA volume index; p < 0.001). In multivariate analysis, only the difference between the baseline and follow-up LASR(R) values (Δ: LASR(R); odds ratio (OR) 0.037, 95% confidence interval (CI) 0.003–0.496, p = 0.013) predicted accelerated LA remodeling. A poor baseline LASR(R) was significantly associated with its profound deterioration during the follow-up period (β: = -0.424, p = 0.002). CONCLUSION: In severe chronic Carpentier II MR, a reduced follow-up LASR(R) predicted future accelerated LA remodeling. Patients with a poor baseline LASR(R) are at a higher risk of its deterioration.