Global Diastolic Strain Rate for the Assessment of Left Ventricular Relaxation and Filling Pressures

Abstract

Background— Diastolic strain rate (SR) measurements that comprise all left ventricular (LV) segments are advantageous over myocardial velocity for assessment of diastolic function. Mitral early diastolic velocity (E)/SR ratio during the isovolumetric relaxation (IVR) period can be used to estimate LV filling pressures. Methods and Results— Simultaneous echocardiographic imaging and LV pressure measurements (7F catheters) were performed in 7 adult dogs. Loading conditions were altered by saline infusion and caval occlusion, and lusitropic state was changed by dobutamine and esmolol infusion. A curve depicting global SR was derived from each of the 3 apical views, and SR was measured during IVR (SR IVR ) and early LV filling (SR E ). SR IVR had a strong correlation with time constant of LV pressure decay during the IVR period (τ) ( r =−0.83, P <0.001), whereas SR E was significantly related to LV end-diastolic pressure ( r =0.52, P =0.005) in the experimental stages where τ was <40 ms. In 50 patients with simultaneous right heart catheterization and echocardiographic imaging, mitral E/SR IVR ratio had the best correlation with mean wedge pressure ( r =0.79, P <0.001), as well as in 24 prospective patients ( r =0.84, P =0.001). E/SR IVR was most useful in patients with ratio of E to mitral annulus early diastolic velocity (E/Ea ratio) 8 to 15 and was more accurate than E/Ea in patients with normal ejection fraction and regional dysfunction (both P <0.01). Conclusions— Global SR IVR by 2-dimensional speckle tracking is strongly dependent on LV relaxation. E/SR IVR can predict LV filling pressures with reasonable accuracy, particularly in patients with normal ejection fraction and in those with regional dysfunction.