急性前壁心肌梗塞猪模型左室流场变化的相关研究

The Research on the Left Ventricular Flow Vector Characteristics in Pigs Model of Acute Anterior Myocardial Infarction

目的应用血流向量成像技术(vector flow mapping,VFM)研究滇南小耳猪急性前壁心肌梗塞前后左心室心室腔内血流流场变化特点.方法选取滇南小耳猪18只,在进行常规二维超声检查、VFM图像采集之后,开胸结扎左冠状动脉前降支(LAD)的中下1/3处,于1 h后再次进行常规二维超声检查、VFM图像采集,并分析心腔内血流速度向量、流线和漩涡等左心室流场参数,进行对比分析.结果在急性前壁心肌梗塞后,LVEF、LVFS均减小(P<0.05);心梗后在大部分收缩期内左心室内仍可见涡流,且心梗后的漩涡横径(Dx)、漩涡纵径(Dy)、涡流总持续时间均大于心梗前,差异有统计学意义(P<0.05).结论左心室前间壁心肌梗塞室壁运动减弱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.

Objective To study the left ventricular flow vector characteristics in Diannan Small-Ear pigs with anterior anterior wall myocardial infarction by using vector flow mapping（vector flow mapping, VFM）.Methods Routine echocardiography was performed in 18 Diannan small ear pigs and the flow vector and velocity of left ventricle were analyzed. Then the left anterior descending coronary artery（LAD） was ligated at the lower 1/3 piont,and the same echocardiography was performed again 1 hour after ligation. Some parameters,such as flow velocity vector,streamline and swirling flow field parameters of left ventricle,were comparatively analyzed.Results After acute anterior wall myocardial infarction,LVEF,LVFS were decreased（P〈0.05）. Pig＇s left ventricular intracavitary vortex in the ejection phase was still visible. The pig＇s vortex diameter（Dx）,vortex longitudinal diameter（Dy）,vortex total duration were larger after acute anterior wall myocardial infarction than before. The difference was statistically significant（P〈0.05）.Conclusions The left ventricular vortex extends from diastolic to systolic when aortic valve is opening,as the left ventricular wall motion decreases after their Left ventricular anteroseptal myocardial infarction.It suggests the lower left ventricular regional systolic function may reduce the blood flow velocity and extend the time of the left ventricular vortex,thus reduce the left ventricular intracardiac hydrodynamic efficiency and cardiac stroke volume.