Echocardiography
CONTRACTION
The instruments for echocardiography included Vivid E9 and Vivid E95 ultrasound systems (GE Vingmed Ultrasound, Horten, Norway). The baseline echocardiography for the admitted patients was implemented prior to their coronary angiography. The original data of echocardiography images were stored in DICOM format. EchoPac software (EchoPAC 204, GE Vingmed Ultrasound) was used to analyze conventional, MW, LA indices offline. The performance guidelines of echocardiography were the American Society of Echocardiography guidelines [MW indices were determined by the EchoPAC software, which had a pressure–strain loop area module made from non-invasively estimated LV pressure curves and LV strain. Peak systolic LV pressure was assumed to be equal to the peak brachial cuff systolic blood pressure that was measured simultaneously at the echocardiography examination, which has been reported previously [In addition, the measurement of LA strain was performed using the instrument of AFI LA (EchoPAC 204, GE Vingmed Ultrasound), in which zero strain was defined by the automatic R-wave trigger on the electrocardiogram. EchoPac 204 is equipped with a software package for evaluating LA strain based on the strain values in three phases: reservoir strain in systole (LASr), conduit strain in early diastole (LASct), and contraction strain in late diastole (LAScd).