短暂中断心脏再同步化治疗功能性二尖瓣反流对左心室腔内流场的影响

Effect of Temporary Interruption of Cardiac Resynchronization Therapy on Left Ventricular Flow in Functional Mitral Regurgitation

目的应用血流向量成像图(VFM)评价心脏再同步化治疗(CRT)中长期患者临时短暂中断CRT治疗,功能性二尖瓣反流(FMR)对左心室腔内流场的影响。资料与方法回顾性分析宁夏医科大学总医院2021年1—10月CRT术后6个月以上有轻中度二尖瓣反流患者36例,分别于临时短暂中断CRT前后行超声心动图检查,测量左心室舒张末期容积(LVEDV)及收缩末期容积(LVESV),并计算左心室射血分数(LVEF);采用近端等速表面积(PISA)法定量评估FMR程度,测量二尖瓣有效反流口面积(EROA)及反流容积(MRV)。脉冲波多普勒于心尖左心室长轴切面记录二尖瓣及主动脉瓣频谱,并依据频谱测量收缩期各时相组成:等容收缩期(IVC)为二尖瓣关闭至主动脉瓣开放(AVO)的间期,射血期为AVO至主动脉瓣关闭(AVC)的间期。利用VFM软件采集左心室内血流向量图像,启用涡流模式图,取二尖瓣关闭瞬间、AVO瞬间、涡流观测终点3个时刻,分别测量涡流中心的横向位置、纵向位置、流量、面积并观察其演变特征。结果与中断CRT前比较,中断CRT 15 min后患者的LVEDV、LVESV、EROA、MRV均增加(t=2.356、2.258、4.621,P均<0.05);等容收缩期内纵向位置和涡流面积在AVO时刻中断CRT后小于中断前(t=2.764、2.258,P均<0.05),且等容收缩期涡流流量衰减幅度中断CRT后高于中断前(t=2.414,P<0.05);射血期内纵向位置和涡流面积在涡流观测终点中断CRT后显著大于中断前(t=2.642、2.414,P均<0.05),射血期涡流面积衰减幅度、射血期涡流流量衰减幅度中断后小于中断前(t=2.414、2.642,P均<0.05)。结论短暂中断CRT会加重FMR,同时FMR对于左心室内收缩期血液流畅会造成多方面的不良影响。VFM技术能无创、客观地评价CRT中长期患者暂时中断CRT时FMR对左心室流场的影响。

Purpose The application of vector flow imaging(VFM)evaluation of cardiac resynchronization therapy(CRT)in patients with mid-to-long-term temporary interruption of CRT functional mitral regurgitation on left ventricular flow.Materials and Methods A total of 36 patients with mild to moderate mitral regurgitation after CRT for more than 6 months in General Hospital of Ningxia Medical University from January to October 2021 were examined by echocardiography before and after the CRT was interrupted.Followed by measurement of left ventricular end-diastolic volume(LVEDV)and end-systolic volume(LVESV),And calculate left ventricular ejection fraction(LVEF);Quantitative assessment of FMR was performed using the proximal isovelocity surface area(PISA)method to measure the mitral effective regurgitant orifice area(EROA)and regurgitant volume(MRV).Pulsed wave Doppler in the left ventricular apical long axis view record mitral and aortic valve spectrum,and based on the spectrum measurement systolic phase composition:isovolumic contraction period(IVC)was the interval between mitral valve closing(MVC)and aortic valve opening(AVO);ejection time(ET)was the interval between AVO and aortic valve closure(AVC).VFM software was used to collect vector images of left ventricular blood flow,and the vortex pattern diagram was enabled.The moment of MVC,AVO,and eddy current observation endpoint(END)were used to measure the transverse position(PH),longitudinal position(PL),flow rate(FV),area(VA)of the vortex center and also observe their evolution characteristics.Results Compared with before interruption of CRT,the LVEDV,LVESV,EROA and MRV of patients increased after interruption of CRT 15 min,and the differences were statistically significant(t=2.356,2.258,4.621,all P<0.05);According to the VFM observation during the isovolumic contraction period,the PL and VA were less than before the interruption of the CRT at the AVO time,and the differences were statistically significant(t=2.764,2.258,all P<0.05),and the Vortex flow attenuation amplitude(ΔFV-IVC)during isovolumetric systole was higher than before the interruption of CRT,and the differences were statistically significant(t=2.414,P<0.05).In the ejection phase,the PL and VA were significantly greater than that before interruption at END(t=2.642,2.414,P<0.05),Attenuation range of vortex area in ejection phase(ΔVA-ET)and the attenuation rate of the vortex flow in the ejection phase(ΔFV-ET)were significantly smaller than those before the interruption,and the differences were statistically significant(t=2.414,2.642,P<0.05).Conclusion Temporary interruption of CRT may aggravate FMR,and FMR may cause multiple adverse effects on systolic blood flow in the left ventricle.VFM can noninvasively and objectively evaluate the effect of temporary interruption of CRT functional mitral regurgitation on left ventricular flow field in patients with CRT.VFM technique can noninvasively and objectively evaluate the effect of temporary interruption of CRT functional mitral regurgitation on left ventricular flow field in long-term CRT patients.