title: Hemodynamic determinants of the mitral annulus diastolic velocities by tissue Doppler.
abstract: OBJECTIVE
  Our goal was to identify the hemodynamic determinants of the mitral annulus (MA) diastolic velocities by tissue Doppler.
  
  
  BACKGROUND
  The MA diastolic velocities are promising indexes of left ventricular (LV) diastolic function. However, their hemodynamic determinants have not yet been evaluated.
  
  
  METHODS
  Ten adult mongrel dogs underwent left atrial (LA) and LV pressure measurements by Millar catheters while tissue Doppler was applied to record the MA diastolic velocities at the septal and lateral comers. Conventional transmitral flow was also obtained. Left atrial and LV pressures were modified utilizing fluid administration and caval occlusion, whereas dobutamine and esmolol were used to change LV and LA relaxation. Left ventricular filling pressures were altered during different lusitropic states to evaluate for the possible interaction of preload and LV relaxation on the early diastolic velocity (Ea).
  
  
  RESULTS
  In the majority of dogs, a positive significant relation was observed between Ea and the transmitral pressure gradient (r = 0.57, p = 0.04). The 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 experimental stages where tau >50 ms. Furthermore, the late diastolic velocity 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 inverse correlation with LV end-diastolic pressure (r = -0.53, p = 0.01).
  
  
  CONCLUSIONS
  Left ventricular relaxation, minimal pressure and preload determine Ea while late diastolic velocity determinants include LA dP/dt, LA relaxation and LV end-diastolic pressure.
authors.affiliation: Department of Medicine, Baylor College of Medicine, Houston, Texas, USA. sherifn@bcm.tmc.edu
authors.forename: S F
authors.initials: SF
authors.lastname: Nagueh
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.forename: H A
authors.initials: HA
authors.lastname: Kopelen
authors.forename: K J
authors.initials: KJ
authors.lastname: Middleton
authors.forename: D S
authors.initials: DS
authors.lastname: Khoury
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D003971:Diastole / Q000502:physiology*; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D009200:Myocardial Contraction / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology