右心室流出道起源室性期前收缩患者左心室腔流场分布模式的研究

目的 分析正常人及右室流出道(right ventricular outflow tract,RVOT)起源室性期前收缩(premature ventricular complexes,PVCs)患者左心室腔等容收缩期涡流及左心室腔不同层面时间-血流曲线分布规律，探讨RVOT起源PVCs对左心室腔流场分布模式的影响。方法 分别获取27例RVOT起源PVCs患者在窦性心搏、室性期前收缩时及25例正常人的心尖四腔观二维彩色多普勒血流图。应用血流向量标测(vector flow mapping，VFM)技术，在涡流模式下分析等容收缩期左心室腔涡流直径（横径、纵径）、速度（最大正向速度、最大负向速度）、圈数；获取左心室腔基底段至心尖段各层面时间-血流曲线，分别测量各层面收缩期负向、舒张期正向血流量。结果 与正常对照组比较，RVOT起源PVCs患者在室性期前收缩时，等容收缩期所形成涡流的涡流直径、速度、圈数均降低（P均＜0.01），左心室腔时间-血流曲线杂乱；窦性心搏时等容收缩期涡流的速度降低，左心室流量分布规律改变。结论 RVOT起源PVCs患者在窦性心搏及室性期前收缩时均存在左心室腔流场分布模式的改变,VFM技术能够用于标测正常及异常电激动状态下左心室腔内血液流场的变化。

Study of intracardiac flow patterns of left ventricle in patients with premature ventricular complexes from the right ventricular outflow tract

Objective To evaluate the patterns of intracardiac flow of left ventricle (LV) in patients with premature ventricular complexes (PVCs) from the right ventricular outflow tract (RVOT) by analyzing the vortex during isovolumetric contraction phase and the distribution rules of flow-time curves in each layer of LV.Methods Twenty-seven patients with frequent isolated PVCs from RVOT were involved and 25 healthy subjects as control.The color Doppler image of LV at apical four-chamber view was acquired.Vector flow mapping (VFM) was performed to assess the parameters of vortex during isovolumic contraction phase, including diameter (transverse and vertical diameter), velocity (maximal positive and negative velocity) and the number of vortex rings.Positive flow during systole and negative flow during diastole of LV in each layer were measured by flow-time curve.All values of patients with PVCs were recorded during sinus beats (PVC-S) and PVC (PVC-V) respectively.Results Significant differences were demonstrated in all parameters of vortex between the PVC-V and control subjects.And the flow-time curves disarrayed in PVC-V.The velocity of vortex in PVC-S was lower than that in control subjects.And the distribution pattern of flow-time curves in LV of PVC-S differed from that of control subjects.Conclusions Alternation of intracardiac fluid pattern in LV was demonstrated in patients with PVCs from RVOT during both sinus beats and PVC.VFM can be used to analyze the intracardiac flow field in normal and pathological electrical activation.