Mitral inflow velocity, left atrium contraction inflow velocity in early diastole and their ratio were detected by Doppler flow imaging.Difference of the index of the two groups was compared.

• 并用二尖瓣血流多普勒法检测舒张期早期血流速度峰值、左心房收缩期血流速度峰值及二者比值，比较两组间所测指标的差异。