Fig. 4: Normal human mitral annulus model and dynamic saddle shape geometry changes.

a The interpolated cubit spline fit of an exemplary normal human mitral annulus at midsystole. Note the prominent saddle shape. The black markers in a clockwise direction starting in the anterior segment represent the posteromedial commissure, left trigone, anterior midpoint, right trigone, anterolateral commissure, and posterior midpoint. The red markers represent the rest of the tracked annulus points. b Mean normal human annular height throughout a cardiac cycle. The annular height increases in systole. c Mean normal human annular height to intercommissural distance ratio (AHICR) throughout a cardiac cycle. The AHICR increases throughout systole. d Mean normal human intercommissural distance throughout a cardiac cycle. The intercommissural distance remains relatively constant. e Mean normal human anteroposterior distance throughout a cardiac cycle. The anteroposterior distance demonstrates a gradual increase. f Mean normal human 2D annular area throughout a cardiac cycle. Shaded areas represent standard error. b–f generated from three human subjects.