Abstract 3563: Relationship Between Ventricular Deformation and Flow During Early Diastole
Background: It has recently been shown that energy stored during systole in the elastic elements of the myocardium is released during isovolumic relaxation (IVR) by rapid untwisting of the left ventricle (LV), generating intraventricular pressure gradients (IVPG) and assisting in the low-pressure filling of the heart. Peak IVPG coincides with outward movement of the mitral annulus early in diastole, but the role of annulus movement in IVPG generation and consecutive intraventricular flow propagation is unknown.
Methods: we studied 31 healthy controls (age 38±12 yrs, EF 67±6%), 21 HCM subjects (age 46±20 yrs, EF 65±7%), and 19 DCM subjects (age 55±16 yrs, EF 35±12%). Digital color M-mode data were used to obtain flow propagation velocity (Vp) and IVPG. 2-dimensional short-axis apical and basal LV views were analyzed by speckle tracking imaging software (Echopac PC, GE Medical) to obtain corresponding rotation rates. Peak untwisting velocity was then obtained from apico-basal rotation rate difference, while peak LV torsion was calculated by integrating rotation rate difference signal. Early diastolic mitral annulus velocity (Ea) was calculated by averaging pulsed wave Doppler tissue data obtained at the septal and lateral point of the mitral annulus.
Results: Peak torsion and peak untwisting velocity were decreased only in DCM patients. In contrast, Ea was similarly decreased in both HCM and DCM patients, while both Vp and IVPG were decreased more in DCM than in HCM patients. (Table⇓)
Conclusion: Loss of mitral annulus motion in HCM patients leads to small but significant decrease of IVPG and Vp. This indicates that both LV untwisting and mitral annulus motion facilitate early LV filling.