Hemodynamic determinants of the mitral annulus diastolic velocities by tissue Doppler

OBJECTIVES Our goal was to identify the hemodynamic determinants of the mit ral annulus (MA) diastolic velocities by tissue Doppler. BACKGROUND The MA diastolic velocities are promising indexes of left ventri cular (LV) diastolic function. However, their hemodynamic determinants have not yet been evaluated. METHODS Ten adult mongrel dogs underwent left atrial (LA) and LV pressure m easurements by Millar catheters while tissue Doppler was applied to record the MA diastolic velocities at the septal and lateral corners. Conventional transmitral flow was also obtained. Left atrial and LV pressures were modi fied utilizing fluid administration and caval occlusion, whereas dobutamine and esmolol were used to change LV and LA relaxation. Left ventricular fil ling pressures were altered during different lusitropic states to evaluate for the possible interaction of preload and LV relaxation on the early dias tolic velocity (Ea). RESULTS In the majority of dogs, a positive significant relation was observ ed between Ea and the transmitral pressure gradient (r = 0.57, p = 0.04). T he Ea had strong correlations with tau (r = -0.83, p < 0.001), LV -dP/dt (r = 0.8, p < 0.001) and minimal LV pressure (r = -0.76, p < 0.01). However, there was no relation between Ea and the transmitral pressure gradient in e xperimental stages where tau >50 ms. Furthermore, the late diastolic veloci ty at both corners of the MA had significant positive relations with LA dP/ dt (r = 0.67, p < 0.01) and LA relaxation (r = 0.73, p < 0.01) but an inver se correlation with LV end-diastolic pressure (r = -0.53, p = 0.01). CONCLUSIONS Left ventricular relaxation, minimal pressure and preload deter mine Ea while late diastolic velocity determinants include LA dP/dt, LA rel axation and LV end-diastolic pressure. (J Am Coil Cardiol 2001;37:278-85) ( C) 2001 by the American College of Cardiology.