This study demonstrates the critical role of ventricular fluid mechanics, specifically a ring-vortex, in the normal diastolic closure of the mitral valve.
A model of the left ventricle was built incorporating a mitral and an aortic valve. The bicuspid mitral valve was seen to achieve most of its closure during diastole. This was shown to be due to a ring-vortex occupying the left ventricle together with flow deceleration through the mitral ring during the latter part of diastole. The vortex was asymmetrical in the model, because of the shape of the ventricle, and this caused the anterior cusp to close earlier in diastole than the posterior cusp. Enlargement of the ventricle eliminated the vortex and resulted in later closure of the mitral valve. The effect of atrial systole on valve closure was studied experimentally and theoretically.
B. J. Bellhouse (Wed,) studied this question.