Key result
In patients with LV enlargement and dysfunction, range and corrected area flux of the IVC vortex, LV end-systolic short diameter, and IVC time independently predicted VLVOT (R2=0.608, P<0.001).
Why the study?
The study investigated the relationship between the left ventricular vortex during isovolumic contraction and preejectional flow velocity in the left ventricular outflow tract.
Observational (n=173)
Effect estimate: R2 = 0.608
p-value: p=<0.001
Vector flow mapping demonstrates that in patients with LV enlargement and dysfunction, momentum transfer to the LV outflow tract depends on the range and volume of the isovolumic contraction vortex.
IVC vortex metrics may refine VLVOT assessment in LV dysfunction; hypothesis-generating and requires prospective validation before clinical use.
Objectives The purpose of this study was to investigate the relationship between the vortex in left ventricle (LV) during the isovolumic contraction (IVC) period and the preejectional flow velocity in LV outflow tract (VLVOT). Methods Color Doppler loops were acquired for vector flow mapping in apical long‐axis view in 76 patients with dilated cardiomyopathy, 61 patients with coronary artery disease and 36 healthy controls. Results All normals exhibited an IVC vortex reaching the LV base. VLVOT was significantly related to IVC vortex area flux, transmitral A velocity, mitral annular a′ velocity and E/e′ ratio, respectively. Transmitral A velocity was the only independent predictor of VLVOT (R2 = 0.292, P = 0.001). In patients the IVC vortex could reach the LV base, middle, or apex. VLVOT was significantly related to range, area and area flux of the IVC vortex, LV size, LVEF, mitral annular velocities, E/e′ ratio, transmitral A velocity, and IVC time, respectively. Range and corrected area flux of the IVC vortex, LV end‐systolic short diameter, and IVC time were independent predictors of VLVOT (R2 = 0.608, P < 0.001). Conclusions In normals, the transmitral A velocity (momentum) is efficiently transferred from mitral orifice to LV outflow tract by a normally formed IVC vortex, and transmitral A velocity is the only independent predictor of VLVOT. However, in patients with a wide range of LV enlargement and dysfunction, the momentum transfer is associated with not only the LV dimension and function, but also the range and volume of the IVC vortex.
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Li et al. (2019) conducted an observational in Dilated cardiomyopathy and coronary artery disease (n=173). Left ventricular vortex during isovolumic contraction vs. Healthy controls was evaluated on Predictors of preejectional flow velocity in LV outflow tract (VLVOT) (R2 = 0.608, p=<0.001). In patients with LV enlargement and dysfunction, range and corrected area flux of the IVC vortex, LV end-systolic short diameter, and IVC time independently predicted VLVOT (R2=0.608, P<0.001).
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