Abstract 12500: Attenuated Basal Left Ventricular Wall Contraction in Patients With Mitral Valve Prolapse Can be Secondary to Annular Dilatation With Augmented Closing Force: Pre- and Post-Operative Speckle Tracking Echocardiographic Study

Introduction: Mitral annulus (MA) is generally enlarged in patients with mitral valve prolapse (MVP), which may raise MV closing force acting to shift the MV and its adjacent basal left ventricular (LV) wall toward left atrium. Hypothesis: MA dilatation with augmented MV closing force may disturb basal LV wall systolic contraction in patients with MVP. Methods: In 11 healthy controls and 34 patients with MVP, 3 apical views were obtained to assess longitudinal strain of basal- and mid-LV segments by speckle tracking analysis. The ratio of basal- to mid-LV strain value was then calculated. MA area was calculated by annulus diameters in apical 4- and 2- chamber views. MV closing force was calculated as MA area х (systolic blood pressure - 10). Results: Patients with MVP showed significantly larger MA area (5.3±1.0 vs 3.8±0.7 cm2/m2) and MV closing force (638±192 vs 431±66 mmHg•cm2/m2), and reduced basal-LV strain (-18±3 vs -21±2%) than controls (all p<0.005), whereas mid-LV strain was similar between the 2 groups (-22±4 vs -22±3%, p=0.4). Consequently, significantly lower basal/middle ratio was observed in patients with MVP compared to controls (0.86±0.11 vs 0.95±0.08, p=0.004). By multivariate analysis, reduced basal/middle strain ratio was associated with augmented MV closing force (β=0.45, p=0.005) (Figure A), independent from the severity of mitral regurgitation (p=0.7). The basal/middle strain ratio significantly increased to 1.07±0.10 after annular size reduction in 5 patients with surgical MV plasty (p=0.04) (Figures B and C). Conclusions: In patients with MVP, an increase in MV closing force corresponding to MA dilatation, as opposed to the severity of mitral regurgitation, was related to attenuated basal LV wall contraction, which can be restored by MV plasty with annular size reduction. ![][1] [1]: /embed/graphic-1.gif