Measurement of cardiac structure and function by echocardiography

According to American Society of Echocardiography leading-edge method, transthoracic color doppler echocardiographic studies were performed and read by experienced cardiologists in a single core laboratory in our hospital, with a Vivid echocardiographic system (General Electric Co., Fairfield, CT, USA), which was equipped with a 3.5-MHz sector scan transducer²⁰. Two-dimensional guided M-mode measurement of right ventricular (RV) diameter, interventricular septal thickness, left ventricular (LV) posterior wall thickness and end-diastolic inner diameter were examined at end-diastole from the parasternal long-axis view; Right atrial (RA), left atrial (LA) and LV end-systolic inner diameter were measured at end-systole from the parasternal long-axis view; The methods for the calculation of LV mass index and ejection fraction were the same as described previously^16,17,20.