Assessment of relationship between preejectional flow velocity and late diastolic vortex in left ventricular chamber by vector flow mapping

  AIM   To clarify the relationship between preejectional flow velocity in left ventricular (LV) outflow tract (V₀) and vortex in LV chamber during late diastole using vector flow mapping (VFM).

  METHODS   Color Doppler flow images were recorded from LV apical long-axis view in 55 healthy volunteers and 123 patients with coronary artery disease. The patients were divided into two groups: patients with LV ejection fraction (LVEF) > 50% and patients with LVEF < 50%. The area and flux of the anterior vortex in LV chamber at end-diastole and V₀ were measured.

  RESULTS   In healthy volunteers, V₀ was moderately related with vortex flux, corrected flux and transmitral A velocity, respectively. Corrected flux of vortex was the only independent predictor of V₀ (R² = 0.283, P < 0.01). Area and flux of vortex in patients with LVEF < 50% were greater than those in the other two groups, whereas corrected flux was lower than those in the other two groups (both P < 0.05). There was no significant difference in corrected vortex area between the three groups. V₀ in patients with LVEF < 50% was lower than those in the other two groups (both P < 0.05) and no significant difference in V₀ was found between the other two groups. In all patients, V₀ was moderately related with corrected vortex flux, LV size, LVEF, and systolic and late diastolic mitral annular velocities (s’ and a’), respectively. LV end-diastolic short diameter (β = −0.329, P < 0.01), a’ (β = 0.266, P < 0.01) and corrected vortex flux (β = 0.188, P < 0.05) were the independent predictors of V₀.

  CONCLUSION   The preejectional flow velocity in LV outflow tract is closely related to the vortex occurring during late LV diastole. The momentum of transmitral flow during late diastole can be transferred to LV outflow tract by the vortex, which facilitates LV ejection.