Subclinical Left Ventricular Dysfunction in Asymptomatic Chronic Mitral Regurgitation Patients with Normal Ejection Fraction: A Combined Tissue Doppler and Velocity Vector Imaging-Based Study

BACKGROUND: The optimal timing of the surgery in asymptomatic severe mitral regurgitation (MR) remains a challenge. The aim of the study is to evaluate the subclinical changes in LV longitudinal functions by using a novel strain imaging technique; velocity vector imaging (VVI); in patients with chronic MR. METHODS AND RESULTS: We studied 54 patients with asymptomatic, nonischemic, chronic MR (56.8 ± 9 years and 56% male) and 30 healthy controls (55 ± 6.5 years and 55% male) with normal ejection fraction. Patients with MR were analyzed in tertiles according to their regurgitant volumes (RV) and regurgitant fractions (RF): mild MR (RV < 30 mL, RF < 30% n = 7), moderate MR (RV: 30-59 mL, RF = 30-50%; n = 29), and severe MR (RV > 60 mL, RF ≥ 50%; n = 18). Conventional echocardiography and VVI-based strain imaging were performed to analyze LV functions. LV longitudinal peak systolic strain and strain rate (SRs) were significantly impaired in moderate and severe MR patients. Changes in LV longitudinal deformation were more significant in patients with severe MR. All deformation parameters showed a marked negative correlation with RV (LV Strain r =-0.583, P = 0.0001; LV SR r =-0.408, P = 0.002, respectively). CONCLUSIONS: LV long-axis functions are important markers of LV contractility in MR patients. Novel echocardiographic techniques may provide additional data on subclinical changes in the LV and give way to the optimal timing for the surgery in severe MR patients.