中文摘要：

目的应用应变成像（SI）和应变率成像（SRI）技术评价不同二尖瓣置换术式对左心室收缩功能的影响。方法根据是否保留瓣下结构将55例二尖瓣置换患者分为3组，A组20例为未保留瓣下结构，B组20例为保留后叶瓣下结构，C组15例为保留全部瓣下结构。分别于术前、术后7～10天及术后3个月行超声检查，对比分析3组患者瓣膜置换前后心肌收缩期峰值应变（Ss）和收缩期峰值应变率（SRs）变化情况。结果术后7～10天，3组心肌Ss和SRs差异无统计学意义；术后3个月，C组心肌Ss和SRs改善优于B组和A组；B组心肌ss和SRs改善优于A组。结论二尖瓣置换术中保留全部二尖瓣瓣下结构更有利于术后心功能恢复。

英文摘要：

Objective To investigate the changes of left systolic ventricular function after mitral valve replacement with different degrees of chordal preservation by using strain and strain rate imaging. Methods A total of 55 patients undergo- ing mitral valve replacement were enrolled, including 20 receiving complete excision of the subvalvular apparatus （group A）, 20 receiving preservation of the posterior chordopapillary apparatus only （group B） and 15 receiving total chordal pres- ervation of chordal preservation （group C）. Systolic peak strain （Ss） and systolic peak strain rate （SRs） were measured be- fore operation, 7--10 days and 3 months after operation. Results No significant difference of Ss nor SRs was found among 3 groups 7--10 days after operation. Three months later, Ss and SRs were significant different between each two groups, the changes of Ss and SRs in group C were greater than those in group B and A, in group B were greater than those in group A. Conclusion Mitral valve replacement with preservation of total subvalvular apparatus is beneficial to the recovery of heart function.