应用速度向量显像技术评价正常人及肥厚型心肌病患者的心肌扭转

Assessment of left ventricular rotation by velocity vector imaging

目的应用速度向量显像技术研究正常人和肥厚型心肌病（HCM）患者的左心室心肌扭转方式。方法对25例健康志愿者（对照组）和41例HCM患者（HCM组）行常规超声心动图检查，采集二尖瓣水平短轴观、心尖水平短轴观、心尖四腔观及心尖二腔观二维图像，得到左室舒张末期容积、收缩末期容积、左室射血分数和室壁厚度。脱机分析得到收缩期心底部心内膜、心外膜和心尖部心内膜、心外膜的扭转速度峰值及扭转位移峰值，并分别计算心底部内外膜扭转速度／位移差值及心尖部内外膜扭转速度／位移差值。结果收缩期心室扭转在心底部呈顺时针，在心尖部则呈逆时针，心尖部扭转幅度显著大于心底部（P〈0．05或P〈0．001），心内膜扭转显著大于心外膜（P〈0．01或P〈0．001）。扭转速度一时间曲线由一个收缩期峰和两个舒张期峰组成，扭转位移一时间曲线由一个舒张末期的小峰和一个收缩期的大峰组成。HCM组心底部呈不对称性肥厚，在显著肥厚的节段，HCM组心肌内外膜扭转速度／位移差值显著大于对照组（P〈0．01或P〈0．001）。结论速度向量显像技术能够简便准确地评价心室扭转，并能够发现HCM患者内外膜心肌扭转的不协调性。

Objective To investigate left ventricular rotation in healthy subjects and patients with hypertrophy cardiomyopathy（HCM）. Methods Twenty-five healthy subjects and 41 patients with HCM were enrolled. Two-dimensional standard echocardiography were performed and analyzed using Siemens Sequoia C512 system and velocity vector imaging 2.0 version. Left ventricular end diastolic volume（EDV）, end systolic volume（ESV）, left ventricular ejection fraction（LVEF）, systolic peak rotation velocity and displacement of endocardium and epicardium of basal and apical part of left ventricle were measured. Difference of basal and apical rotation velocity and displacement between endocardium and epicardium （DVbase,DVape,DDbase,DDape） were calculated. Results Left ventricle rotated clockwise at basal part and counterclockwise at apex during systole. It rotated stronger at apex（ P〈0.05 or P〈0. 001 ） than at basal part and stronger in endocardium than in epicardium（ P 〈0.01 or P 〈0. 001 ）. The rotation velocitytime curve consisted of a peak during systole and two peak during diastole,while the rotation displacementtime curve was composed of a smaller diastolic peak and a larger systolic peak. There was asymmetrical hypertrophy at the basal part of HCM patients,and DVbase and DDbase were significantly increased （ P〈0.01 or P〈0. 001） in the significant hypertrophy segment. Conclusions Velocity vector imaging can assess left ventricular rotation effectively. HCM patients acquire mismatch of endocardium and epicardium rotation.