How ventricular pressure drop can affect the mitral valve dynamics

The present paper describes the mechanisms responsible for dynamical motion of the mitral valve annulus during diastole. Several studies have suggested that the mitral annulus displacement and velocity in early diastole can be used as indicators of diastolic performance. The peak velocity of the mitral annulus away from the left ventricular (LV) apex during early diastole which indicates the rate of longitudinal expansion of the LV is reduced in patients with impaired diastolic relaxation. With the intention of relating the trans-mitral flow to mitral annulus plane dynamics, we experimentally measured mitral annulus recoil force, while applying an exponential pressure drop in a mechanical model of the left ventricle. The temporal changes in diameter of the mitral valve during rapid filling phase were also considered. The process of trans-mitral vortex ring formation was studied together with the measurement of mitral annulus recoil force within different pressure drop conditions. Matching the vorticity contour plots with the recoil force measurements resulted in the fact that the magnitude of recoil is maximal once the vortex ring is about to pinch off, regardless of the mitral valve size or the characteristics of ventricular pressure drop.

http://www.springerlink.com/content/w855565623w0g223/