速度向量成像技术评价扩张型心肌病心脏扭转运动

Assessment of cardiac twist in dilated cardiomyopathy using echocardiography velocity vector imaging

目的应用超声心动图速度向量成像（VVI）技术对扩张型心肌病（DCM）患者心脏扭转运动的改变进行初步分析，进一步探讨VVI技术在评价心脏扭转运动方面的价值。方法采用VVI技术对33名正常人和30例扩张型心肌病患者进行研究。选取胸骨旁左室二尖瓣水平、乳头肌水平、心尖水平短轴切面及心尖四腔心、两腔心切面的图像，测量收缩期左室基底部、中部及心尖部最大旋转角度、峰值旋转速度、圆周应变（CS），达峰值旋转速度时间（TPRV）；舒张末期及等容舒张末期峰值解旋转速度，对比两组心脏旋转和扭转运动。结果（1）正常组左室扭转运动：自心尖部向心底部观察，等容收缩期心底部逆时针旋转，心尖部顺时针旋转；收缩期心底部顺时针旋转，心尖部逆时针旋转；乳头肌水平旋转形式不固定。左室整体扭转方向为逆时针。（2）部分DCM患者心脏扭转运动形式改变：30例研究对象中4例患者左室扭转形式不同于正常人，其中2例表现为心尖和心底均呈逆时针旋转，1例表现为心尖和心底均呈顺时针旋转，1例表现为心底部呈逆时针旋转而心尖部呈顺时针旋转。（3）旋转形式未发生变化的26例DCM患者的有关旋转和扭转运动参数均明显减低，以心尖部减低更为明显。DCM组与正常组相比：左室扭转角度7．34°±3．65°比17．01°±4．81°、扭矩（0．09±0．04）°／mm比（0．23±0．06）°／mm、扭转速度（60．23±23．67）°／s比（148．24±56．23）°／s、解扭转率（0．37±0．19）％／m比（0．59±0．33）％／m；心底部旋转角度-3．60°±2．38。比-6．56°±3．18°（P=0．014）、心尖部旋转角度5．80°±3．55°比12．13°±2．05°（P=0．000）、心底部CS-8．09％±2．73％比-19．49％±5．51％（P=0．013）、心尖部CS-8．94％±5．90％比-27．49％±9．53％（P=0．000）。（4）左室扭转角度与射血分数呈正相关（r=0．489，P〈0．05），DCM组心尖部TPRV较正常组明显延长，存在旋转运动不同步性（400．26±70．15）ms比（328．13±66．95）ms，P=0．008。结论（1）DCM心脏扭转功能呈弥漫性损伤，扭转功能受损对心脏整体功能的减低具有明显影响。（2）部分DCM心脏扭转运动形式表现与正常人不同。（3）VVI可客观反映DCM患者的心脏扭转功能。

[ Abstract] Objective To assess cardiac twist in dilated cardiomyopathy （DCM） patients using echocardiography velocity vector imaging （VVI） and to explore the clinical application value of VVI in evaluating cardiac twist. Methods Thirty-three normal subjects and 30 DCM patients were enrolled. Eehocardiographs of parasternal left ventricle basal, papillary muscle level and apical short axis plane, apical four-, two-chamber plane were obtained respectively. Systolic maximal rotation degree, peak rotation velocity, circumferential strain （CS）, time to peak rotation velocity （TPRV）, peak un-rotation velocity of end diastole and end isovolumic relaxation period in subendocardium were measured by VVI software. Results （1） In the normal group, left ventricle performed systolic wring motion with counterclockwise rotation at the apex and clockwise rotation at the base as seen from the apex, while with transient counterclockwise rotation at the base and clockwise rotation at the apex in isovolumic relaxation period. The papillary level rotation form was not constant. For the dominant rotation action of the apex, the whole cardiac twist form was counterclockwise. （2） Compared with the control group, 4 DCM patients cardiac twist pattern changed： two showed both counterclockwise rotation of the base and the apex, one represented both clockwise rotation of the base and the apex, another performed the base rotated counterclockwise and the apex rotated clockwise. （ 3 ） All rotation and twist parameters of other 26 DCM patients decreased, especially at the apical level： LVtw：7.34° ±3.65° vs 17.01° ±4.81°, LVtor：（0.09 ±0.04）°/mm vs （0.23 ± 0. 06） °/mm, torsion rate： （ 60. 23 ± 23.67 ） °/s vs （ 148.24 ± 56. 23 ） °/s, untwisting rate （ 0. 37 ± 0.19）%/m vs （0.59 ±0.33%）/m, basal CS：（ -8.09 ±2.73）% vs （ -19.49 ±5.51）% （P= 0.013）, apical CS：（ -8.94±5.90）% vs （ -27.49 ±9.53）% （P=0.000）, basal rotation angle： （ - 3.60 ± 2. 38 ） °vs （ - 6. 28 ± 3.05 ）° （ P = 0. 014）, apical rotation angle ： （ 5.80 ± 3.55 ） ° vs （ 11.02 ± 3.33 ）°（P = 0. 001 ）. （4） The apical TPRV in DCM group were longer than the control group represented rotational dyssynchrony in DCM patients （400. 26 ms±70. 15 ms vs 328.13 ms ±66. 95 ms, P =0. 008）. LVtw correlated positively well with EF （r = 0. 489, P 〈 0. 05 ）. Conclusion （ 1 ） Cardiac twist function was diffusely impaired in DCM patients and it contributed to the global cardiac dysfunction. （2） Cardiac twist pattern changed in some of DCM patients. （3） VVI can objectively reflect cardiac twist function in DCM patients.