2.2 Standard Echocardiographic Examination
Transthoracic echocardiographic examinations were performed with S5-1 probe, 1-5MHz (CX50, Phillip, Netherlands). Two-dimensional (2D) and Doppler echocardiography were performed according to the guidelines of the American Society of Echocardiography5. The following echocardiographic views were recorded over three cardiac cycles: left parasternal long- and short axis views and apical two‐ apical three- and apical four‐chamber views. Images were recorded on external hard disk and stored in digital format for offline analysis (Q-lab 10.8.5). The right ventricular anteroposterior diameter and LV diameter, left atrial (LA) diameter, LV interventricular septum (IVS) and LV posterior wall (LVPW) thickness and aortic diameter were measured at long axis view. The right atrial (RA) diameter was measured at apical four-chamber view. The pulmonary diameter was measured at pulmonary long axis view. LV systolic function included LV volumes, left ventricular ejection fraction (LVEF) were measured by the modified biplane Simpson’s rule. Mitral, aortic and pulmonary artery Doppler flow profiles were recorded, including maximum mitral inflow velocity at early (E) and late (A) diastole. Pulsed tissue Doppler imaging was obtained with the sample volume placed at the septum of mitral valve and free wall of tricuspid valve at the apical 4-chamber view. Velocity of mitral annulus at early diastole (e’), late diastolic myocardial a’) velocities, and RV TDI-s were recorded. The E/e’ ratio, being recorded at the level of the septum of the mitral annulus, was used as an index of LV filling pressure. Tricuspid annular plane systolic excursion (TAPSE) was measured in apical four-chamber view via placing the cursor at the tricuspid anterior annulus and measuring the distance of systolic annular RV excursion along a longitudinal line. All images were collected by an experienced investigator in echocardiography who was blinded to the clinical information.