Tissue Doppler-derived myocardial acceleration for evaluation of left ventricular diastolic function

Abstract

Our purpose was to evaluate a tissue Doppler-based index-peak myocardial acceleration (pACC)-during isovolumic relaxation and in evaluating left ventricular (LV) diastolic function. Simple, practical indexes for diastolic function evaluation are lacking, but are much desired for clinical evaluation. We examined eight sheep by using tissue Doppler ultrasound images obtained in the apical four-chamber views to evaluate mitral valve annular velocity at the septum and LV wall. The pACC thus derived was analyzed during isovolumic relaxation (IVRT) and during the LV filling period (LVFP). We then changed the hemodynamic status of each animal by blood administration, dobutamine, and metoprolol infusion. We compared the pACC values during IVRT and LVFP over the four different hemodynamic conditions with a peak rate of drop in LV pressure (-dP/dt(min)) and the time constant of LV isovolumic pressure decay (tau), as measured with a high-frequency manometer-tipped catheter. The pACC of the septal side of the mitral valve annulus during IVRT showed a good correlation with -dP/dt(min) (r = -0.80, p < 0.0001) and tau (r = -0.87, p < 0.0001). The mean left atrial pressure (LAP) correlated well with the septal side pACC during LVFP (r = 0.81, p < 0.0001). There was a weak correlation between the mitral valve annulus pACC at the LV lateral wall and mean LAP. The pACC during IVRT is a sensitive, preload-independent marker for evaluation of LV diastolic function. In addition, pACC during LVFP correlated well with mean LAP.