Echocardiographic methods
All
transthoracic echocardiographic data were performed by a GE Vivid E95
ultrasound machine (GE Healthcare, Oslo, Norway) with cardiac sector
probe M5S and 4V (1.0–1.5 Hz), and using Echopac workstation
(Version:201) for offline analyses. Connect the ECG to record the moving
image of at least five cardiac cycles (frame rate>40fps),
to ensure the image is clear (endocardium) and complete (including
epicardium), and adjust the frame rate to 40% of the patient’s heart
rate. All echocardiograms of each patient were obtained by the same
ultrasound machine.
Standard ultrasoundexamination.
Along the parasternal LV long-axis
view measured the LV end-systolic diameter (LVIDS), LV end-diastolic
diameter (LVIDD), LV posterior wall thickness (LVPW), end-systolic
volume (ESV), end-diastolic volume (EDV). LVEF as indicators to assess
left ventricular systolic function was calculated by the modified
Simpson biplane method, with images recoded from
apical two-chamber and apical
four-chamber views. Fractional shortening (FS) was derived from M-mode
imaging.
In
the apical four-chamber section, the mean value of early diastolic peak
velocity (e’) of septal and lateral mitral annulus was computed by
tissue Doppler and pulsed Doppler imaging. The E/e′ ratio was calculated
by the ratio of the peak early transmission velocity (E) to the average
e’. Then FS and E/e′ ratio could be used to evaluate left ventricular
diastolic function [16]. Moreover, we used M-mode and tissue Doppler
imaging echocardiography methods to measure isovolumic relaxation time
(IRT), isovolumic contraction time (ICT) and ejection time (ET), and
then Tei index((IRT+ICT)/ET) was computed automatically by the
ultrasonic system as a reliable estimate of left ventricular global
function[17]. These data were
expressed as averages of three consecutive cycles.