Abstract 2282: Left Ventricular Geometry Independently Affects Mitral Flow Propagation Velocity And Early Diastolic Intraventricular Pressure Gradient in Both Normal And Diseased Ventricle
Introduction: Patients with hypertrophic (HCM), as opposed to dilated (DCM) cardiomyopathy, have higher flow propagation velocity (Vp), early disatolic intraventricular pressure gradient (IVPG) and left ventricular (LV) untwisting velocity. It is unknown if these differences are intrinsic or due to load or relaxation.
Methods: We performed echocardiography in 40 controls, 27 HCM, and 56 DCM patients. Vp and IVPG (measured by Euler equation) were obtained from the color M mode of the mitral inflow. LV untwisting velocity (Untw) was measured by speckle tracking imaging while mitral annular early diastolic velocity (Ea) was obtained from color Doppler tissue data (Echopac PC, GE Medical USA). We correlated each of these parameters with transmitral E wave velocity, time constant(τ) of isovolumic pressure decay (τ = isovolumic relaxation time/[ln(systolic pressure)-ln(pulmonary wedge pressure)]) and the ratio of LV end-systolic volume divided by mass (LVV/LVM) as representative of LV geometry in a stepwise multiple regression. The combination of transmitral E wave velocity and τ served as a marker of the impact of preload and relaxation.
Results: Mean LVV/LVM was 0.34± 0.09 in normal subjects, 0.15±0.06 in HCM and 0.65± 0.25 in DCM patients (p<0.001 for all groups). After correction for τ and E wave velocity, LVV/LVM remained a strong independent predictor of Vp (p< 0.001), IVPG (p=0.009) and untwisting velocity (p< 0.001) (Figure⇓). However, LVV/LVM did not affect Ea (p=0.25).
Conclusions: LV geometry independently affects Vp, IVPG and untwisting velocity, but not Ea. LV geometry should be taken into account when considering normal values of these diastolic parameters.