2. Esophageal ultrasonic exclusion criteria： LVEF≤30%; Presence of left atrial appendage thrombus; High risk PFO patients(presence of atrial septal aneurysm); Have obvious mitral valve stenosis (the area of mitral valve≤ 2 cm2); Have obvious and unexplained pericardial effusion(≥4 cm2). Presence of complex aortic plague(≥4 mm) in ascending aorta.