Analysis by VFM
Optimized two-dimensional ultrasound color movies of the apical
three-chamber view were transferred to a computer with the VFM software
DAS-RS1 (Hitachi Ltd., Tokyo, Japan). Each image of one cardiac cycle
was selected using electrocardiography. All aliasing phenomena were
checked, and the aliasing area was manually corrected. The LV
endocardial boundary was initially traced manually and was then traced
automatically throughout the remaining frames. The software used
calculated intracardiac EL in one cardiac cycle from VFM images.
By echocardiography and electrocardiography, one cardiac cycle was
separated into the following three phases: ED, LD and Sys. ED was
defined as the phase from the opening of the mitral valve to before the
start of atrial contraction. LD was defined as the phase from the start
of atrial contraction to the closing of the mitral valve. Peak EL in
each phase was collected as a parameter. An example of the VFM analysis
in the present study is shown in Figure 1.