【作者】 张晓娟；

【导师】 智光；

【作者基本信息】 中国人民解放军军医进修学院 ， 心血管内科， 2009， 博士

【摘要】 左室机械运动包括纵向运动、径向运动和扭转运动,目前左室的扭转与解旋运动已成为评价机械功能的一个全新的指标,目前心脏再同步化治疗是药物治疗外一项有效治疗心力衰竭的策略。本研究拟采用速度向量成像技术(Velocity Vector Imaging,VVI)评价心脏扭转与解旋运动及心脏各方向运动的失同步性,本研究内容如下:1.正常人左室扭转及解旋特征的研究选择94例健康志愿者,按照年龄分为青年组(21例,男15例,女6例,年龄18-45岁,平均31.71±10.04岁)、中年组(44例,男15例,女29例,年龄46-64岁,平均55.86±9.57岁)、老年组(22例,男10例,女12例,年龄65-79岁,平均71.66±15.73岁)、老老年组(7例,男2例,女5例,年龄≥80岁,平均83.00±4.17岁),观察正常人随着年龄增加左室扭转及解旋特征。结果:正常人左室心底部与心尖部心肌旋转角度、旋转速度曲线随心动周期规律变化;随着年龄增加,左室收缩期最大扭转角度(Ptw)、收缩末(主动脉瓣关闭时)左室扭转角度(AVCtw)、等容舒张末(二尖瓣开放时)左室扭转角度(MVOtw)及解旋速度(PUV)逐渐增加,二尖瓣开放时间(Time at MVO)逐渐延长,主动脉瓣关闭时间(Time at AVC)未见明显变化,左室Ptw在青年组为(16.33±3.63)°、中年组为(20.08±4.87)°、老年组为(23.24±5.84)°、老老年组为(23.03±2.08)°,AVCtw在青年组为(13.40±3.32)°、中年组为(16.73±4.60)°、老年组为(18.95±5.36)°、老老年组为(18.96±1.75)°;MVOtw在青年组为(8.93±3.13)°、中年组为(11.06±3.82)°、老年组为(12.66±4.07)°、老老年组为(12.78±1.64)°;解旋率(untwR)在青年组为(0.59±0.20)%、中年组为(0.47±0.12)%、老年组为(0.39±0.11)%、老老年组为(0.30±0.06)%,随着年龄的增加逐渐降低,各组间比较除老年组与老老年组之间没有统计学差异,余各组间比较均具有统计学差异(P＜0.01),其中解旋率与年龄呈负相关,Ptw、AVCtw、MVOtw、PUV、PTV与年龄呈正相关。2.扩心病患者左室扭转及解旋特征的研究选择扩张型心肌病(Dilated Cardiomyopathy,DCM)组患者19例(男性17例,女性2例,年龄18～82岁,平均50.52±17.52岁)),健康体检者21例(男性16例,女性5例,年龄18～80岁,平均49.05±16.94岁)作为对照组,扩心病患者按照E/A分为E/A＜2、E/A＞2两个亚组,结果显示:常规超声显示DCM组LVDd值增大,EF值减小;DCM患者左室心底部与心尖部心肌旋转角度、旋转速度随心动周期变化曲线明显紊乱;与正常组比较,DCM患者左室整体扭转角度和速度分别为(6.49±1.82)°、(67.84±15.60)°/s,较正常人显著减低(P＜0.01);左室舒张末及收缩末扭转角度DCM患者较正常人显著减低(P＜0.01),左室舒张末及收缩末时间在DCM-E/A＞2组较正常人及DCM-E/A＜2组显著缩短(P＜0.01);DCM患者左室解旋速度较正常人亦显著减低(P＜0.01),左室功能轻中度减低(DCM-E/A＜2)患者解旋率[(0.29±0.07)%]较正常人[(0.42±0.11)%]明显减低,但当左室功能重度减低(DCM-E/A＞2)时左室解旋率[(0.63±0.35)%]较正常人反而增加;左室整体扭转角度、舒张末扭转角度、收缩末扭转角度、解旋与左室射血分数未见明显相关性。3.速度向量成像技术在CRT中的应用本研究入选了心力衰竭并接受CRT治疗的患者28例,所有患者术前心脏失同步性评估均提示存在左室内失同步,但左室内延迟收缩的部位个体间存在较大的差异,其中以后壁最为常见,其次为侧壁、下壁;本研究规定患者术后发生心衰相关的死亡或左室收缩末容量较术前减少＜15%视为CRT无效,28例CRT患者中21患者治疗有效,7例患者CRT治疗无效,无效率25%;随访观察发现1个月、3个月就可见临床、心功能、活动耐量的显著改善,左室内失同步性也显著改善;本研究对左室失同步性的进一步研究发现:所有患者术前左室长轴存在失同步性,左室短轴方向也存在失同步性,短轴心底面6个节段的速度峰时间的最大-最小差值在CRT治疗有效、无效患者之间的差异较显著,左室短轴心底面最大差值(Ts max-min basal)对CRT治疗的预测价值最大(ROC曲线下面积为0.86),其灵敏度为81%,特异度为86%,截点为97.5ms;短轴12个节段的Ts-SD(ROC曲线下面积为0.80)的灵敏度、特异度均为76%,截点为57.8,短轴12个节段TS max-min(ROC曲线下面积为0.76,灵敏度为76%。特异度为72%,截点为121.5ms),长轴12个节段的Ts-SD(ROC曲线下面积为0.51,灵敏度为76%,特异度为39%,截点为43.2)及Ts max-min(ROC曲线下面积为0.52,灵敏度76%,特异度为43%,截点为136.4ms)也具有一定的预测价值,但较短轴稍差。综上所述,本研究结论如下:1.正常人与DCM患者左室心底部与心尖部心肌旋转角度、旋转速度曲线随心动周期规律变化,左室心尖部旋转速度方向舒张期主要呈顺时针方向;心底部舒张期主要表现为逆时针方向旋转;2.正常人心脏存在左室扭转、解旋运动,左室扭转角度、扭转速度随着年龄增加而增加,左室解旋速度随着年龄增加而增加,但左室解旋率随年龄增加而减小;3.DCM患者心脏扭转角度、扭转速度较正常人显著减弱,左室解旋率变化与左室功能有关,心功能重度减低时解旋率反而增加,这提示解旋率可能受前负荷程度的影响;4.心衰患者存在左室失同步,CRT可以改善患者心功能、活动耐量,改善左室失同步性;VVI技术通过评估左室长轴、短轴失同步性对CRT治疗效果提供一定的预测价值,其中以短轴Ts max-min basal的预测价值最为显著,其次为短轴12个节段的Ts-SD及Ts max-min。更多还原

【Abstract】 The left ventricular mechanical motion included longitudinal motion,radial motion and twisting.And the twisting and untwisting of left ventricle have been new indexes of the heart function.Cardiac resynchronization therapy(CRT) has been shown to a valuble stragy for heart failure patients.In this study,we want to assess the twisting,untwisting and desynchronization of left ventricle in long and short axis,and the contents of this study were the following:1.Assessment of left ventricular twisting and untwistingof healthy volunteers 94 healthy volunteers were assigned to four groups by age,young-group(range 18-45 yr,mean age 31.71±10.04 yr,6 females and 15 males), middle-age-group(range 46-64 yr,mean age 55.86±9.57 yr,29 females and 15 males),older-age-group(range 65-79 yr,mean age 71.66±15.73 yr,12 females and 10 males) and very-old-age-group(80≥yr,mean age 83.00±4.17 yr,5 females and 2 males).The results show that LV rotation degree,rotation velocity at baseline and apex were regular changed with the cardiac cycle;the rotation direction was clockwise at the base and counterclockwise at the apex,and is combined to yield a systolic counterclockwise twisting as seen from the apex. With aging,Ptw,AVCtw,MVOtw,PTV and PUV increased significantly(P＜0. 05) and UntwR decreased significantly(P＜0.05) in the young-group, middle-age-group and older-age-group,However no difference in all indexes was noted among the older-age-group and very-old-age-group.Ptw at young-group, middle-age group,old-age group and very-old-age group were(16.33±3.63)°, (20.08±4.87)°,(23.24±5.84)°and(23.03±2.08)°,AVCtw at young-group, middle-age group,old-age group and very-old-age group were(13.40±3.32)°, (16.73±4.60)°,(18.95±5.36)°and(18.96±1.75)°,MVOtw at young-group, middle-age group,old-age group and very-old-age group were(8.93±3.13)°, (11.06±3.82)°,(12.66±4.07)°and(12.78±1.64)°,the UntwR at young-group, middle-age group,old-age group and very-old-age group were(0.59±0.20)%, (0.47±0.12)%,(0.39±0.11)%and(0.30±0.06)%.There was a good correlation between Ptw,AVCtw,MVOtw,PTV,PUV,UntwR and age.2.Assessment of left ventricular twisting and untwisting of DCM patients19 DCM patients(range 18-80 yr,mean age 50.52±17.52 yr,2 females) and 21 age- and sex-matched normal controls(range18-80 yr,mean age 49.05±16.94 yr,5 females) were enrolled into this study.Then DCM patients were divided into two groups:E/A＜2 group and E/A＞2 group.The routine echo showed the left ventricle dilated and EF decreased.The results show that LV rotation degree, rotation velocity at baseline and apex were irregular changeable with the cardiac cycle;the rotation direction was clockwise at the base and counterclockwise at the apex,and are combined to yield a systolic counterclockwise twisting as seen from the apex,but the rotation at the basal and apex were the same direction in some patients.Ptw,AVCtw,MVOtw,PTV,PUV decreased significantly in DCM patients,and the UntwR was significantly decreased in the E/A＜2 group.But there was no correlation between Ptw,AVCtw,MVOtw,PTV,PUV,UntwR and EF in DCM patients.3.Application of Velocity Vector Imaging in cardiac resynchronization therapyVelocity vector imaging was applied to of 28 patients with heart failure who underwent cardiac resynchronization therapy.That velocity vector imaging can quantify left ventricular mechanical desynchronization before CRT therapy,but the delay contractile position was different in different patient,and the posterior wall was the most common delay contractile position.Long-term response to CRT was defined as a＞15%reduction in the left ventricular end systolic volume at 3 months of follow-up,so there were 21 responders and 7 non-responders;CRT has been shown to improve the heart function,activity toleration and desynchronization in responders.In this study,and predict response.The Ts max-min basal velocity time delays of 97.5 ms predicted response with 81% sensitivity and 86%specificity when followed(12.08±7.51) months after resynchronization therapy.Therefore,we come to the conclusions:1.The rotation direction in normal people and DCM patients was clockwise at the base and counterclockwise at the apex,and are combined to yield a systolic counterclockwise twisting as seen from the apex2.With aging,Ptw,AVCtw,MVOtw,PTV and PUV increased significantly and UntwR decreased significantly in normal people.3.Ptw,AVCtw,MVOtw,PTV,PUV decreased significantly in DCM patients,the UntwR was significantly decreased in the E/A＜2 group,but increase in the E/A＞2 group,this result indicated the UntwR may be effected by the pre-load.4.There was desynchronization in dysfunction heart;CRT therapy can improve the heart function and activity toleration;Ts max-min basal can predict CRT response with the highest sensitivity and specificity in both the short and longitudinal axis desynchronization更多还原