Basal Left Ventricular Dilatation and Reduced Contraction in Patients With Mitral Valve Prolapse Can Be Secondary to Annular Dilatation

Typical patients with MVP, especially global leaflet prolapse or Barlow type prolapse, have prominent MV annular dilatation with only modest LV dilatation. This discrepancy suggests that patients with MVP and annular dilatation frequently have basal predominance of LV dilatation (Figure 1). Predominantly, basal LV dilatation may cause greater systolic wall tension in the LV base compared with the middle and apical segments by Laplace’s law, which may lead to regionally attenuated contraction in the LV base. We, therefore, hypothesized that a dilated MV annulus in patients with MVP may be related to the basal predominance of LV dilatation and reduced contraction. We further hypothesized that such basal Background—Prominent mitral valve (MV) annular dilatation with only modest left ventricular (LV) dilatation in patients with MV prolapse (MVP) suggests predominant dilatation in adjacent basal LV, which may augment regional wall tension and attenuate contraction by Laplace’s law. We hypothesized that MV annular dilatation in patients with MVP is associated with the basal predominance of LV dilatation and attenuated contraction, which can be altered by surgical MV plasty with annulus reduction. Methods and Results—Echocardiography with speckle-tracking analysis to assess regional cross-sectional short-axis area and longitudinal contraction (strain) of basal, middle, and apical LV was performed in 30 controls and 130 patients with MVP. The basal value/averaged middle and apical values (B/M·A ratio) of LV cross-sectional area and strain were obtained. Patients with MVP showed significantly greater MV annular area (6.4±1.6 versus 3.7±0.6 cm/m), increased B/M·A LV area ratio (2.4±0.5 versus 1.8±0.2), and reduced B/M·A LV strain ratio (0.83±0.14 versus 0.96±0.09) than controls (P<0.001). Multivariable analyses identified that MV annular dilatation was independently associated with increased B/M·A LV area ratio (β=0.60, P<0.001), which was associated with reduced B/M·A LV strain ratio (β=−0.32, P<0.001). In 35 patients with MVP, B/M·A LV area and strain ratio significantly altered after surgical MV plasty with annulus reduction (2.5±0.5–1.8±0.3 and 0.73±0.10–0.89±0.17, P<0.001, respectively). Conclusions—In patients with MVP, MV annular dilatation was associated with the basal predominance of LV dilatation and reduced contraction, which can be altered by surgical MV plasty with annulus reduction, suggesting unfavorable influence from MV annular dilatation on basal LV. (Circ Cardiovasc Imaging. 2016;9:e005113. DOI: 10.1161/ CIRCIMAGING.115.005113.)