前壁心肌梗塞患者左室壁三维运动与左室流场变化相关性研究

目的应用血流向量成像技术（vector flow mapping,VFM）和三维斑点追踪技术（three-dimensional speckle tracking 3DT）,研究正常人和前壁心肌梗塞室壁节段性运动异常患者的心室腔内血流流场、流体力学状态与心肌机械力学状态间的关联关系.方法选取健康成人30例、前壁心肌梗塞患者30例,首先进行常规二维超声检查,之后分别进行实时全容积成像三维成像图像采集和VFM图像采集,在获取左心室全容积图像后分析图像,自动计算左心室旋转角度（rotation angle,RA）、各节段室壁运动峰值径向应变（Radial strain,RS）等参数,在VFM血流图像中分析心腔内血流速度向量、流线和漩涡等左心室流场参数.结果病例组与健康对照组相比,病例组LVEDV增大、LVEF减小（P〈0.05）;病例组在射血期左心室心腔内仍可见占据绝大部分左心室心腔的整体涡流;病例组的漩涡横径（Dx）、漩涡纵径（Dy）、涡流总持续时间均大于健康对照组,差异有统计学意义（P〈0.05）;病例组左心室旋转角度（rotation angle,RA）、旋转率（rotation rate,RR）、扭转角度（twist angle,TA）及扭转率（twistrate,TR）越小射血期左心室内涡流范围越大（漩涡横径Dx、漩涡纵径Dy增大）,持续时间越长,成显著负相关（r=-0.693,r=-0.751,r=-0.655,r=-0.672,P〈0.05）.结论左心室前间隔中间段、前壁中间段、心尖段RS、AS减低直接导致了本来在左心室内舒张期形成的涡流直接延续到了收缩期主动脉瓣开放之后,提示左心室重构以后心室形态改变,局部收缩功能减低导致了左心室内血流速度减低以及涡流持续时间延长,从而降低了左心室心腔内流体力学效率,使心脏搏出量减少.

The Correlation between Left Ventricular Flow Vector Characteristics and Left Ventricular Wall Motion in Patients with Anterior Myocardial Infarction

Objective To study the correlation between Left ventricular flow vector characteristics and left ventricular wall motion in normal people and patients with anterior wall myocardial infarction and abnormal segmental ventricular wall motion by using vector flow mapping（vector flow mapping,VFM） and three dimensional speckle tracking（three-dimensional speckle tracking 3DT）. Methods Echocardiography was performed in 30 patients with anterior myocardial infarction and 30 healthy people. Flow vector and velocity of left ventricle were analyzed on apical 3 chambers view with color Doppler. The left ventricle（LV） rotation angle（RA）,rotation rate（RR）,torsion angle（TA） and torsion rate（TR） in the apical full-volume image were measured and compared by using three-dimensional speckle tracking imaging.Results Compared with the healthy control group, patient group＇s LVEDV increased, LVEF decreased（P〈0.05）.Patient＇s left ventricular intracavitary vortex in the ejection phase was still visible. The patient＇s vortex diameter（Dx）,vortex longitudinal diameter（Dy）,vortex total duration were larger than those in the healthy control group. There was a significant difference in them between the patient group and control group（P〈0.05）. The lower patient＇s left ventricular rotation angle（rotation angle,RA）,rotation rate（rotation rate,RR）,torsion angle（twist angle, TA） and the rate of twist（twist rate,TR）,the larger vortex Dx and Dy,and the vortex duration was longer. There was a significantly negative correlation（r=-0.693,r=-0.751,r=-0.655,r=-0.672,P〈0.05）. Conclusions The patient＇s left ventricular vortex formed in diastolic period may extend to systolic period when aortic valve is opening, this results directly from the reduction of RS and AS in left ventricular anterior septal middle segment,anterior wall middle segment and apical segment. The results suggest that after left ventricular remodeling,the ventricular morphous changes,the lower left ventricular