Background-Leaflet curvature is known to reduce mechanical stress. There are 2 major components that contribute to this curvature. Leaflet billowing introduces the most obvious form of leaflet curvature. The saddle shape of the mitral annulus imparts a more subtle form of leaflet curvature. This study explores the relative contributions of leaflet billowing and annular shape on leaflet curvature and stress distribution. Methods and Results-Both numerical simulation and experimental data were used. The simulation consisted of an array of numerically generated mitral annular phantoms encompassing flat to markedly saddle-shaped annular heights. Highest peak leaflet stresses occurred for the flat annulus. As saddle height increased, peak stresses decreased. The minimum peak leaflet stress occurred at an annular height to commissural width ratio of 15% to 25%. The second phase involved data acquisition for the annulus from 3 humans by 3D echocardiography, 3 sheep by sonomicrometry array localization, 2 sheep by 3D echocardiography, and 2 baboons by 3D echocardiography. All 3 species imaged had annuli of a similar shape, with an annular height to commissural width ratio of 10% to 15%. Conclusion-The saddle shape of the mitral annulus confers a mechanical advantage to the leaflets by adding curvature.This may be valuable when leaflet curvature becomes reduced due to diminished leaflet billowing caused by annular dilatation. The fact that the saddle shape is conserved across mammalian species provides indirect evidence of the advantages it confers. This analysis of mitral annular contour may prove applicable in developing the next generation of mitral annular prostheses.

Semi-automated detection of the LV endocardial surface from RT3DE data is suitable for clinical use because it allows rapid, accurate, and reproducible measurements of LV volumes, superior to conventional 2DE methods.

Automated simultaneous quantification of LA and LV volumes and LVEF is feasible and requires minimal 3D software analysis training. The automated measurements are not only comparable to manual measurements but also to CMR. This technique is highly reproducible and timesaving, and it therefore promises to facilitate the integration of 3D TTE-based left-heart chamber quantification into clinical practice.

Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus ( P <0.0001), a reduced annular height to commissural width ratio (AHCWR) ( P <0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces ( P <0.0001), greater leaflet billow volume ( P <0.0001) and billow height ( P <0.0001), longer lengths from papillary muscles to coaptation ( P <0.0001), and more frequent chordal rupture ( P <0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%–20%, and <15%, respectively; P =0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture ( r 2 =0.66, P <0.0001). MR severity correlated strongly with leaflet billow volume ( r 2 =0.74, P <0.0001) and inversely with AHCWR ( r 2 =0.44, P <0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P =0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.