AUTO-ESTIMATION
OF THE PROPAGATION VELOCITY OF LEFT VENTRICULAR DIASTOLIC FLOW: FEASIBILITY
STUDY
Chen SB,
Chen S, Wang RF
Dept of
Pediatric Cardiology, XinHua Hospital,
Shanghai
Children's Medical Center, Shanghai, China
Objective: The propagation velocity
(Vp) of left ventricular (LV) diastolic flow derived from color M-mode
doppler echocardiography is reported to be a useful index of LV diastolic
function. Current methods to subjectively determine the slope of the
maximal velocity affect the accuracy of estimation. This study sought to
evaluate the feasibility of auto-estimation of Vp of LV diastolic flow.
Methods: Software was designed
to recognize different color and bright of pixel. Color doppler first
aliasing technique was adopted in this study. After locating ROI at mitral
valve orifice to near LV apex, the slope of the peak velocity of early
diastolic flow could be obtained with custom-made soft ware. A color M-mode
doppler images of LV diastolic flow and its Vp were obtained from apical two
and four chamber views in 25 patients with congenital heart disease, with
mean age of 5 years old. Within 24 hours of the doppler examinations,
cardiac catheterization was performed. -dp/dt and tau of LV were calculated
from pressure tracings.
Results: There was no
significant difference between Vp (56.25+11.5 cm/s) obtained from apical
four chamber view image and Vp (57.59+10.48 cm/s) obtained from apical two
chamber view image. -dp/dt of LV was 1821.1+368.1 mmHg, tau of LV was
26.01+5.4 ms in this group. Vp of LV diastolic flow obtained by
auto-estimation closely correlated with tau of LV ( r=0.75, 0.61, p=0.0001,
0.0047).
Conclusion: Vp of LV diastolic flow
measured from color M-mode doppler images with auto-estimation technique
correlated well with tau determined by cardiac catheterization. It
indicates that auto-estimation technique could be successfully used in
measuring Vp of LV diastolic flow.