Equipment and methods: (1) TTE: MK-600 ultrasound equipment of ATL company and HP-500 or 1500 color Doppler diagnostic apparatus were used. Patients were examined with multi-posture and multi-section by TTE.

• 仪器设备和方法：门）177E检查采用 ATL ’AY司 MKnd00型超声仪及 HP500或 1500型彩色多普勒诊断仪，进行多体位多切面检查。