血流向量图评价心脏再同步化治疗中长期患者暂时中断起搏器前后左心室流场演变

摘要

目的 应用血流向量图(VFM)评价心脏再同步化治疗(CRT)中长期患者暂时中断起搏器前后左室收缩期血液流场变化特征以及心功能变化情况.方法 严格按照入选标准选择起搏器植入术后6个月以上的对CRT有反应的患者32例,分别于中断起搏器前后行超声心动图检查,依次测量左室短轴舒张末内径(LVEDD)及收缩末内径(LVESD),左室舒张末容积(LVEDV)及收缩末容积(LVESV),并计算左室射血分数(LVEF),测量左室压力最大上升速率(LVDp/Dtmax),主动脉瓣上血流速度时间积分(AV-VTI),二尖瓣反流容积(MRV)、面积(MRA).利用VFM软件采集左室内血流向量图像,启用涡流模式图,取二尖瓣关闭瞬间(MVC)、主动脉瓣开放瞬间(AVO)、主动脉血流速度达峰瞬间(APV)以及主动脉瓣关闭瞬间(AVC)四个节点,分别测量涡流的横径(DH)、纵径(DL)、流量(FV)、深度(VD),计算涡流面积(VA),计算从主动脉瓣开放到主动脉血流速度达峰时涡流流量的衰减率(FV-CR％)和面积的衰减率(VA-CR％),并观察其演变特征.结果 与起搏器关闭前比较,关闭起搏器10 min后患者的AV-VTI、LVDp/Dtmax均降低,差异均具有统计学意义(P＜0.05);据VFM观测从主动脉瓣开放到主动脉血流速度达峰时左室腔FV-CR％、VA-CR％均减低,差异均具有统计学意义(P＜0.01);且LVEF与VA-CR％存在正相关,起搏器关闭前后其相关系数分别为0.632(P＜0.01)和0.654(P＜0.01).结论 暂时中断起搏器后常规超声心动图测量参数及VFM参数均出现明显恶化.VFM技术能够客观有效地反映中断起搏器前后左室收缩期血液流场特征的改变与左室功能的变化及其相关关系,并提示远期持续CRT治疗的必要性.%Objective To evaluate left ventricular systolic function and intra-cardiac flow field before and after temporary interruption of pacemaker in mid-to-long-term cardiac resynchronization therapy patients by vector flow mapping (VFM).Methods In strict accordance with the inclusion criteria,32 patients with pacemaker implantation of more than 6 months and responding to CRT were selected.Echocardiographic examination were carried out with Aloka α1 0 ultrasonic diagnostic system in all patients.Regular indices were measured including the sizes of left ventricle,left ventricular ejection fraction (LVEF),the maximal rise rates of left ventricular pressure (LVDp/Dtmax),aortic supravalvular flow velocity time integral (AV-VTI),and the mitral regurgitant volume (MRV),area (MRA).Afterwards,left ventricular blood flow vector image were acquired by VFM software.The center position of longitudinal (VD),diameters (DL and DH),area (VA) and flow volume (FV) of vortex were measured at mitral valve closing moment (MVC),aortic opening moment (AVO),aortic flow velocity peak moment (AVP),and aortic closing moment (AVC).And with further,the FV change rate of (FV-CR％) and the VA change rate (VACR％) during the period of time from AVO to AVP were measured,and their evolution characteristics were observed.Results Compared those indices before closing pacemaker with them after 10 minutes of closing,AV-VTI and LVDp/Dtmax were all decreased (P ＜0.05) ;Aecording to the results of VFM analysis,FVCR％ and VA-CR％ were both decreased during the period of time from AVO to AVP (P ＜0.01).Conclusions There were significant worsening effects on intra-ventricular hemodynamics and flow field characteristics when temporarily interrupted the pacemaker in mid-to-long-term CRT patients.The changes could be easily and objectively analyzed by VFM technique,and the results indicated the necessity of continuous CRT in those patients.