DTI检测缺血心肌左室舒张功能损伤特征的研究

目的　利用DTI技术研究缺血心肌左室舒张功能损伤特征。方法　对 2 4例疑似冠心病患者进行冠脉造影 ,在造影前后同步检测左室压力和左室后壁心肌舒张期运动速度的变化。结果　心肌缺血后左室舒张最低压显著升高 (P <0 0 5 ) ,而左室?p/dt、LVEDP和T常数无明显变化 ;心肌缺血后舒张早期左室后壁心肌运动速度明显下降 (P <0 0 1) ,晚期运动速度无明显变化 ;心肌缺血时左室后壁心肌舒张早期心内膜运动速度显著下降(P <0 0 1) ,心内 外膜速度梯度负值增大 (P <0 0 1)。结论　心内膜对缺血最敏感 ,缺血首先使舒张期心内膜运动速度下降 ,导致舒张早期室壁运动减弱 ,舒张功能异常。

FEATURES OF IMPAIRED LEFT VENTRICULAR DIASTOLIC FUNCTION DUE TO MYOCARDIAL ISCHEMIA AS DETECTED BY DTI

Objective To study the features of abnormal left ventricular diastolic function in ischemic myocardium by DTI (Doppler Tissue Imaging). Methods Left ventricular diastolic function was studied before and after coronary angiography in 24 patients suspected to have myocardial ischemia, left ventricular pressure parameters were obtained by left cardiac catheterization and diastolic velocity of left ventricular posterior wall (LVPW) was measured by DTI at the same time. Results 1.The lowest left ventricular diastolic pressure increased significantly during ischemia of myocardium(P<0.05), whereas the -dp/dt, LVEDP and T constant showed no significant change. 2. The early diastolic velocity of LVPW was significantly decreased during ischemia of myocardium (P<0.01), whereas the late diastolic velocity did not show significant change. 3. The early diastolic velocity of LVPW intramural regional myocardium was significantly decreased (P<0.01) and myocardial velocity gradient from intra-myocardium to peri-myocardium was significantly increased (P<0.001) during ischemia. Conclusions The endocardium is most sensitive to ischemia, therefore ischemia a decrease in diastolic velocity of intramural myocardium, contributing to weakening of early diastolic ventricular wall contractility and abnormal left ventricular diastolic function.