Noninvasive estimation of impaired left ventricular untwisting velocity by peak early diastolic intra-ventricular pressure gradients using vector flow mapping.

Abstract

Introduction of vector flow mapping (VFM) based on the combination of color Doppler and speckle-tracking echocardiography provides noninvasive assessment of early diastolic intra-ventricular pressure gradient (ED-IVPG). The purpose of this study was to evaluate the value of peak ED-IVPG measurement just after aortic valve closure using VFM for noninvasive estimation of impaired LV untwisting velocity as the index of LV relaxation in the clinical setting. The study included 65 consecutive patients in whom echocardiography was performed for the assessment of LV function. We assessed peak ED-IVPG between LV apex and base by VFM analysis software. We also measured peak LV untwisting velocity and LV twisting by speckle-tracking strain analysis. Peak ED-IVPG was successfully and quickly assessed in all the study patients. Peak ED-IVPG was significantly reduced in patients with impaired peak LV untwisting velocity (< 70 degrees/s) compared with patients without impaired peak LV untwisting velocity. The receiver operating characteristic analysis showed the best cut-off value of peak ED-IVPG for determining impaired peak LV untwisting velocity was 0.40mmHg (sensitivity 81%, specificity 74%, and area under the curve 0.81). There was a well correlation between peak ED-IVPG and peak LV untwisting velocity (r = 0.64, p < 0.0001). The present results suggest that peak ED-IVPG just after aortic valve closure measured by VFM may be used as noninvasive index for estimation of impaired LV untwisting velocity in the clinical setting.