应用血流向量图研究左心室射血期涡流变化

Study of evolution of left ventricular intracavitary vortex during ejection using vector flow mapping

目的应用血流向量图(vector flow mapping,VFM)技术研究正常人和心功能衰竭患者射血期涡流的变化特点。方法扩张性心肌病患者[左心室射血分数(LVEF)< 50%]63例组成心衰组,对照组包括健康志愿者50例。心尖左心室长轴观记录左心室彩色多普勒血流信号用于涡流分析。结果对照组射血期左心室涡流迅速消散,消散位置主要位于基底水平二尖瓣下。心衰组射血期涡流持续时间较对照组增加,射血中期涡流面积与流量均大于对照组,差异均具有显著性意义(均P < 0.01);涡流持续位置主要位于心尖水平。结论正常左心室射血期涡流迅速消散,而扩张性心肌病心衰患者涡流持续存在于心尖部,提示射血期涡流的变化与左心室结构、功能密切相关。

AIM To investigate the evolution of the left ventricular (LV) intracavitary vortex during LV ejection in healthy subjects and patients with heart failure using vector flow mapping (VFM). METHODS VFM was performed from LV apical long-axis view in 50 healthy volunteers and 63 patients with dilated cardiomyopathy (LV ejection fraction < 50%). RESULTS In healthy subjects, the intraventricular vortex dissipated quickly during early ejection. The vortex decreased and disappeared mainly at the base of LV chamber (e.g., under the closed mitral valve). In patients with heart failure, the vortex stayed or disappeared mainly at LV apex during LV ejection. Compared with controls, patients with heart failure had a significantly longer duration of the vortex during the period of LV ejection and larger area and flow volume of the vortex at the middle of LV ejection (all, P < 0.001). CONCLUSIONS In patients with heart failure, the vortex persists and stays mainly at apex during LV ejection, whereas the vortex dissipates quickly during early ejection under the closed mitral valve in healthy subjects, suggesting that the evolution of the intraventricular vortex during LV ejection is associated with LV dimensions and functions.