血流向量成像技术对非瓣膜性心房颤动患者左心耳血流流场特点的定量分析

目的 应用经食管超声心动图（TEE）和血流向量成像(VFM)技术研究非瓣膜性心房颤动（简称房颤）患者左心耳流场向量、涡流及能量损耗（EL）的特点。方法 选取接受TEE检查的非瓣膜性房颤患者35例，包括阵发性房颤组20例和持续性房颤组15例，对照组为同期接受TEE检查的窦性心律者12例，采用VFM技术分析不同心律状态下左心耳的血流动力学变化。结果 ①房颤组与窦性心律组相比，心率、左房内径、左心耳内径及血流速度的差异有统计学意义（P<0.05）。②窦性心律组及阵发性房颤组收缩早期和舒张晚期左心耳向量分布规则均匀，收缩晚期和舒张早期向量稀疏、紊乱；持续性房颤组多数于整个心动周期出现规则均匀的向量，但向量方向持续变化。③窦性心律组及阵发性房颤组舒张晚期观察到左心耳开口处的小涡流。④窦性心律组和阵发性房颤组左心耳流场EL于收缩早期及舒张晚期出现峰值，持续性房颤组左心耳流场EL多数在各时相均维持较高值。结论 VFM技术可以清晰显示不同心律状态下左心耳的流场特点，为评估房颤患者左心耳血流动力学提供了一种新方法。

Quantitative Measurements on the Blood Flow Fields of Left Atrial Appendage using Vector Flow Mapping in Patients with Nonvalvular Atrial Fibrillation

Objective To quantify the hemodynamic characteristics of patients with nonvalvular atrial fibrillation. Methods Twenty patients with paroxysmal atrial fibrillation and 15 patients with persistent atrial fibrillation enrolled in this study, while 12 patients with sinus rhythms served as controls. The hemodynamic characteristics of the patients in left atrial appendage were measured by transesophageal echocardiography (TEE) and vector flow mapping (VFM) using indicators such as vectors, vortex and energy loss (EL). Results ① Significant differences appeared between the patients with atrial fibrillation and the controls in heart rate, size of left atrium, size of left atrial appendage (LAA), and velocities of LAA filling and emptying. ② Regular vectors in LAA in early systole and late diastole were found in the patients with paroxysmal atrial fibrillation and the controls; whereas, irregular vectors with direction alternating were visualized in the whole cardiac cycle in the patients with persistent atrial fibrillation. ③ Small vortexes were observed at the opening of the left atrial appendage in late diastole in the patients with paroxysmal atrial fibrillation and the controls. ④ Peak EL values occurred in early systole and late diastole in the patients with paroxysmal atrial fibrillation and the controls. But the patients with persistent atrial fibrillation had increased EL values over the whole cardiac cycle. Conclusion VFM can visualize and quantify the hemodynamics of LAA in patients with different heart rhythms. It may provide a new method for assessing atrial fibrillation.