定量组织速度成像技术评价心肌梗死患者局部心肌的收缩后收缩

Postsystolic shortening in regional myocardium of myocardial infarction patients assessed by quantitative tissue velocity imaging

目的 探讨定量组织成像技术 (QTVI)评价 3支血管病变的心肌梗死患者左心室局部心肌各时期纵向运动特点和在等容舒张期出现的收缩后收缩现象及临床意义。方法 应用定量组织速度成像技术评价 3 0例心肌梗死患者 (MI组 )和 3 0例无任何心脏疾患者 (对照组 )的左心室局部心肌 ,获得纵向上不同壁的基底段和中间段同步多普勒速度、时间速度积分曲线 ,测量其等容收缩期 (IVC)、射血期 (S)、等容舒张期 (IVR)、快速充盈期 (E)、心房收缩期 (A)的峰值速度 (VIC、VS、VIR、VE、VA)和最大时间速度积分 (TVImax)。结果 MI组纵向上心肌各节段运动峰值速度均较对照组下降 ,梗死节段更明显。等容舒张期多个节段出现的异常正向波提示收缩后收缩。此外 ,梗死组多个节段时间速度积分出现收缩期末和等容舒张期两个波峰 ,TVImax较对照组明显下降。结论 3支病变血管的心肌梗死患者收缩和舒张功能明显减低 ;等容舒张期的异常活动提示收缩后收缩 ,存在局部心肌的室壁运动异常 ;等容舒张期的VIR是局部心肌室壁运动异常和心肌缺血的标志。

Objective By quantitative tissue velocity i maging(QTVI),to observe longitudinal wall motion characteristics during isovolumic contraction, ejection, isovolumic relaxation, early relaxation, atrial systole phases in regional myocardium of myocardial infarction patients with three diseased blood vessels, and to assess postsystolic shortening in isovolumic relaxation phase and its clinical meanings. Methods Left ventricular regional myocardium of 30 myocardial infarction patients (MI group) and 30 non-cardiac disease subjects (control group) was assessed by QTVI. After dynamic images were collected and information was analyzed off-line, left ventricular myocardial velocity and time velocity integral profiles were acquired along long axis asynchronously in basal and middle segments of different walls, peak velocities (V IC , V S, V IR , V E, V A) during different phases and maximum time velocity integral (TVI max )in regional myocardium was measured. Results Peak velocities(V IC , V S, V IR , V E, V A) in different segments of left ventricular regional myocardium in MI group were lower than those of control group, especially more obviously in infarcted segments. Peak velocity amplitude in ejection declined, but it had positive velocity spike; abnormal positive velocity in isovolumic relaxation phase suggested postsystolic shortening. What's more, time velocity integrals in some segments of MI group had two wave crests, reached maximum in isovolumic relaxation phase, but were still lower than that of control group. Conclusions Systolic and diastolic function in MI patients with three diseased blood vessels are apparently impaired; abnormal movement in isovolumic relaxation phase suggests existence of postsystolic shortening and abnormal wall motion in regional myocardium.V IR is a marker of abnormal regional wall motion and ischemic myocardium.