多普勒组织成像研究缺血心肌等容收缩期运动变化

目的　应用多普勒组织成像技术研究犬心肌缺血前后等容收缩期运动频谱的变化。方法2 3条犬分为A、B两组 ,A组为开胸实验组 ,冠脉左旋支后壁分支结扎前、后分别记录左室后壁短轴方向组织多普勒运动频谱 ;B组为经胸实验组 ,手术结扎冠脉左旋支后壁分支 ,术前及术后 1周经胸记录左室后壁短轴方向组织多普勒运动频谱 ;对照分析正常与缺血室壁收缩期运动频谱。结果　A、B两组正常室壁收缩期频谱包括前向等容收缩波 (IVC1)、后向等容收缩波 (IVC2 )和射血波 (S)。结扎冠脉后IVC1、S峰值显著降低 ,持续时间显著缩短 (P <0 .0 5 ) ;IVC2 峰值显著增大 ,持续时间显著延长 (P <0 .0 5 )。结论　缺血心肌收缩期运动频谱发生了显著变化 ,等容收缩期的频谱改变有可能作为检测心肌功能状态的指标

Assessment of alteration of ischemic myocardium's motion during systole by Doppler tissue imaging

Objective To study the velocity pattern of ischemic myocardium change during systolic phase by Doppler tissue imaging(DTI). Methods Twenty-three dogs were investigated as two groups. In 13 open-chest dogs as group A, regional wall motion abnormalities were induced by occluding branches of left circumflex coronary arteries(LCX). Left ventricular(LV) wall systolic velocity patterns at the mid-wall portion of the middle of LV posterior walls in the short-axis direction were recorded with DTI before and after artery occlusion. Ten dogs as group B were operated to occlude branches of LCX. Before and one week after operation the same parameters were recorded by transthoracic method. Results There were positive velocity peak(IVC 1), negative velocity peak(IVC 2) during isovolumic contraction and positive velocity peak(S) during ejection in DTI spectra of all normal LV posterior walls. The peak velocities of IVC 1 and S decreased significantly, but the peak velocity of IVC 2 increased significantly after occluding branches of LCX in both groups (P< 0.05). The times of IVC 1 and S shortened and the time of IVC 2 prolonged significantly(P< 0.05). Conclusions DTI spectra of ischemic myocardium during systolic phase changes significantly after occluding coronary artery, which suggests the velocity of isovolumic contraction could be the index for detecting the function of myocardium.