宽QRS波左心室节段应变与容积相关性的超声研究

The spatio-temporal relationship of segmental volume and mural strain of left ventricle with wide and narrow QRS complex evaluated by dynamic three-dimensional echocardiography

目的应用动态三维超声心动图和组织多普勒成像(TDI)技术评价不同病因宽QRS波左心室节段应变与容积的相关性。方法采用彩色多普勒超声诊断仪对18例正常健康人、8例束支传导阻滞患者及11例安置起搏器患者分别采集心脏三维容积灰阶图像和组织多普勒二维图像,并应用QLAB分析软件,自动计算左心室17个节段容积和室壁心肌应变值。结果正常组(除前壁心尖段和后壁基底段,11%节段P>0.05)和右束支阻滞组(除室间隔基底段、前壁心尖段和后壁中段,22%节段P>0.05)各节段心肌容积与应变呈负相关(P<0.05),其回归方程中截距依节段递减(基底段>中段>心尖段);左束支阻滞组各节段心肌容积与应变的相关性差(P>0.05),室间隔最明显;起搏器组大部分节段应变与容积无良好相关性(前壁51%节段及后壁36%节段P>0.05),前壁最明显。结论右束支阻滞组左心室心肌收缩运动协调,左束支阻滞组、宽QRS波和窄QRS波起搏组心肌收缩运动不协调,导致节段容积呈不规则改变。

Objective To evaluate the spatio-temporal relationship of left ventricular segmental volume and mural strain in patients with wide and narrow QRS complex of bundle branch block and cardiac pacing. Methods Eight patients with bundle branch block, 2 patients with VVI pacing, 9 patients with DDD pacing and 18 healthy individuals （control group） underwent the examination of dynamic 3-dimensional volume grey-scale and 2-dimensional tissue Doppler echocardiography. Among them, 3 patients with DDD pacing had a narrow QRS complex （ ≤130 ms） and the other 16 patients had a wide QRS complex （ ≥130 ms） on ECG. The segmental volume and mural strain value of left ventricle.were measured and calculated along the anterior interventricular septum, anterior and posterior walls of the left ventricle at the basal, middle and apical segments using a QLAB software. Results There was a negative correlation between segmental volume and mural strain at the same segments of the left ventricle in the control group and patients with right bundle-branch block （RBBB） during one cardiac cycle （ P 〈 0. 05 ） except for anterior apical and posterior basal segment in control group （ in 11% of the segments, P 〉 0. 05 ） and septal basal, anterior apical and posterior middle segment in patients with RBBB （ in 22% of the segments, P 〉 0. 05）. A linear degressive relationship between the changes of segmental volume and mural strain from the basal to apex was demonstrated. However, there was no significant relationship of segmental volume and mural strain in patients with left bundle-branch block （LBBB）, and patients with wide and narrow QRS complex pacing （P 〉 0. 05 ）. The interventricular septum was the most asynchronous position in patients with LBItB, and anterior wall of left ventricle was the most asynchronous positions in patients with cardiac pacing. Conclusions The results demonstrate a synchrony of left ventricular mechanics in patients with RBBB, and an asynchronism of left ventricular mechanical activation in patients with LBBB, wide and narrow QRS complex pacing, which reflects the non- linear remodeling of the spatio-temporal relationship between the left ventricular segmental volume and mural strain.