应用血流向量图技术分析正常人左心室血流动力学特点

目的 应用血流向量图(vector flow mapping,VFM)技术分析正常人左心室血流动力学特点.方法 健康志愿者50例,心尖左室长轴观记录动态彩色多普勒血流图像,VFM技术分析不同心动时相左室内血流速度向量分布特点,观察左室内基本流和涡流的分布情况.结果 等容收缩期左室腔内以整体涡流为主;射血早期主动脉瓣下流出道血流首先加速射人主动脉,流人道一侧出现短暂的局部涡流,射血中、晚期心腔内涡流消失;主动脉瓣关闭前瞬间,左室内血流迅速转向心尖流动,并持续至等容舒张期结束;缓慢充盈期和左房收缩末期,左室出现整体涡流.结论 VFM技术能够检测各心动时相心腔血流向量分布,有望在分析病变心脏血流动力学变化中发挥重要作用.

Hemodynamics of normal left ventricle analyzed by vector flow mapping

Objective To investigate the hemodynamics of left ventricle(LV) in normal subjects by vector flow mapping(VFM)technique.Methods Color Doppler flow images were recorded from apical long-axis view in fifty healthy volunteers.The flow velocity vector in LV chamber during different phase of cardiac cycle was analyzed by VFM.Results During the isovolumic contraction.the LV was full of a large globe vortex.During the early ejection.the flow under the aortic valve was accelerated and ejected into the aorta.There were some brief local vortexes observed in the LV inflow at the early ejection and these vortexes disappeared during the mid and late ejection.At the instant of aortic valve closure,the intraventricular flow redirected rapidly from the base to the apex and persisted to the end of isovolumic relaxation.During the slow LV filling and left atrial contraction,a large global vortex occurred in the LV chamber again.Conclusions The distribution of flow velocity vector in the LV chamber can be detected by VFM during different phase of cardiac cycle.VFM would be a useful method for the investigation of hemodynamics in diseased heart.