Time-motion reconstruction of mitral leaflet motion from two-dimensional echocardiography in mitral valve prolapse

To assess the contributions of mitral leaflet billowing and exaggerated systolic mitral anular expansion to posterior motion of mitral leaflets recognized as mitral valve prolapse (MVP) by M-mode echocardiography, time-motion reconstructions of the anteroposterior displacement of points equally spaced along the anterior and posterior mitral leaflets were derived by computer-assisted analysis of 2-dimensional echocardiograms. Late or holosystolic posterior displacement of mitral leaflets, greater than or equal to 2 mm, occurred in the reconstructions from 24 of 24 (100%) patients with MVP with leaflet billowing and in 20 of 24 (83%) patients with MVP without leaflet billowing compared with 4 of 35 (11%) age-sex matched normal adults (both p less than 0.0000002). Posterior motion of the posterior mitral leaflet in time-motion reconstruction was significantly less with respect to the posterior end of the mitral anulus than with respect to the chest wall in patients with nonbillowing MVP (1.6 +/- 1.9 vs 2.7 +/- 1.6, p less than 0.02), but not in those with leaflet billowing (3.6 +/- 1.8 vs 3.9 +/- 1.8, p = not significant), because anular expansion contributed importantly to MVP in the former but not in the latter group. Thus, M-mode echocardiographic patterns of MVP reflect the separate but interacting effects of distinct abnormalities of mitral anular and leaflet dynamics.