2.3 Echocardiographic image analysis
(1) RT-3DE: Philips Qlab 10. 4 software was used to off-line analyze the
full-volume image. In the 3DQA mode, the left atrial volume curve was
obtained, and we recorded the maximal, minimal and pre-atrial
contraction left atrial volume (LAVmax, LAVmin, LAVp). Then, each left
atrial volume index (LAVImax, LAVImin, LAVIp) was obtained by
normalizing BSA. Finally, we calculated LATEF, LAAEF and LAPEF. the
calculation method was as follows: LATEF=
(LAVImax-LAVImin)/LAVImax×100%; LAAEF= (LAVIp-LAVImin)/LAVIp×100%;
LAPEF= (LAVImax-LAVIp)/LAVImax×100%. (2) 2D-STI: Off-line analysis of
apical two-chamber and four-chamber images of four consecutive cardiac
cycles using Philips Qlab 10. 4 software. In the aCMQ mode, we recorded
the intima of the left atrium and plotted the region of interest to
obtain the left atrial strain curve. LASr, LASct and LAScd were recorded
respectively, and the strain values of the the two views were added
together and included in the analysis after averaging. The mean peak
strain during left atrial systole, late diastole and early diastole
respectively represents LASr, LASct and LAScd. Where LASr is positive,
LASct and LAScd are both negative, so the absolute value was taken and
analyzed.