Influence of Ventricular Pressure Drop on Mitral Annulus Dynamics Through the Process of Vortex Ring Formation
- 339 Downloads
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 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 measured mitral annulus recoil force for different valve sizes, while applying an exponential pressure drop in a simplified model of the ventricle. The temporal changes in diameter of the valve during rapid filling phase were also considered. The process of ventricular vortex 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 valve size or the characteristics of ventricular pressure drop. This study showed that the mitral annulus recoil is maximal once occurs at the vortex formation time ranging from 3.5 to 4.5. It was also shown that the presence of leaflets would dissipate the annulus recoil force.
KeywordsVortex ring Vortex formation time Left ventricle Diastole Mitral annulus recoil
Authors would like to acknowledge Edwards Lifesciences corp. for providing the bioprosthetic heart valves for this study.
- 1.Alam M., Höglund C. Assessment by echocardiogram of left ventricular diastolic function in healthy subjects using the atrioventricular plane displacement. Am. J. Cardiol. 69:505–565, 1992Google Scholar
- 2.Appleton C. P. Doppler assessment of left ventricular diastolic function: the refinements continue. J. Am. Coll. Cardiol. 2:1697–1700, 1993Google Scholar
- 16.Garcia M. J., Smedira N. G., Greenberg N. L., Main M., Firstenberg M. S., Odabashian J., Thomas J. D. Color M-mode Doppler flow propagation velocity is a preload insensitive index of left ventricular relaxation: animal and human validation. J. Am. Coll. Cardiol. 35:201–208, 2000PubMedCrossRefGoogle Scholar
- 20.Glasson J. R., Green G. R., Nistal J. F. et al. Mitral annular size and shape in sheep with annuloplasty rings. J. Thorac. Cardiovasc. Surg. 117:302–309, 1998Google Scholar
- 21.Glasson J. R., Komeda M., Daughters G. T. et al. Most ovine mitral annular three-dimensional size reduction occurs before ventricular systole and is abolished with ventricular pacing. Circulation 96(Suppl II):115–122, 1997Google Scholar
- 24.Guyton, A. C., and J. E. Hall. Textbook of Medical Physiology, 10th edn. WB Saunders Company, 2000Google Scholar
- 26.Hung M. J., Cherng W. J., Kuo L. T., Wang C. H., Chern M. S. Analysis of left atrial volume change rate during left ventricular diastolic phase with M-mode echocardiography for differentiation between normal and pseudonormal mitral inflow. Am. J. Cardiol. 89(5):552–556, 2002PubMedCrossRefGoogle Scholar
- 44.Ommen S. R., Nishimura R. A., Appleton C. P., Miller F. A., Oh J. K., Redfield M. M., Tajik A. J. Clinical utility of Doppler echocardiography and tissue Doppler imaging in the estimation of left ventricular filling pressures: a comparative simultaneous Doppler-catheterization study. Circulation 102:1788–1794, 2000PubMedGoogle Scholar
- 49.Rodriguez F., Langer F., Harrington K. B., Tibayan F. A., Zasio M. K., Cheng A., Liang D., Daughters G. T., Covell J. W., Criscione J. C., Ingels N. B., Miller D. C. Importance of mitral valve second-order chordae for left ventricular geometry, wall thickening mechanics, and global systolic function. Circulation 110(11 Suppl 1):II115–122, 2004PubMedGoogle Scholar
- 52.Standring S (2004) Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 39th edn. Edinburgh: Churchill LivingstoneGoogle Scholar
- 54.Su H. M., Lin T. H., Voon W. C., Lee K. T., Chu C. S., Lai W. T., Sheu S. H. Differentiation of left ventricular diastolic dysfunction, identification of pseudonormal/restrictive mitral inflow pattern and determination of left ventricular filling pressure by Tei index obtained from tissue Doppler echocardiography. Echocardiography 23(4):287–294, 2006PubMedCrossRefGoogle Scholar