【作者】 陈玉媛；

【导师】 谢明星；

【作者基本信息】 华中科技大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 舒张性心力衰竭(diastolic heart failure, DHF)是一组具有心力衰竭症状和体征而左室射血分数正常,以舒张功能异常为特征的临床综合征。流行病学调查数据显示DHF具有较高的发病率和病死率。发病率占所有心力衰竭病例一半以上,病死率与收缩性心力衰竭(systolic heart failure, SHF)相似,但预后明显优于SHF患者。静息状态下,DHF患者左室每搏输出量及射血分数正常,但其左室形态结构及心肌收缩功能正常与否仍存在争议,维持射血分数正常的机制尚不清楚。心肌扭转和应变在心脏功能中起至关重要的作用,是反映左室功能的敏感指标。新近发展的二维斑点追踪(Two-dimensional speckle tracking imaging, 2D-STI)技术通过实时跟踪同一位置心肌在不同帧频间的运动轨迹,可准确、无创地测量左室旋转角度,径向、纵向、环向应变及应变率等参数,能对左室心肌形变及扭转运动进行定性和定量分析,为评价心脏的局部与整体运动力学提供全新的定量方法。本研究旨在运用2D-STI技术评价DHF患者左室内、外膜层心肌旋转运动及径向应变率变化特征,以期为早期准确评价DHF患者心功能提供一种新方法。第一部分二维斑点追踪成像技术评价舒张性心力衰竭患者左室局部收缩功能应用2D-STI技术评价DHF患者左室心肌局部收缩功能。入选DHF患者32例,SHF患者20例。结果显示:①正常受检者左室各节段径向应变率曲线呈收缩期正向波和舒张早期、晚期负向波的三主波形态;同一水平不同室壁节段间径向应变率峰值无明显差异。②DHF患者及SHF患者室壁各节段径向应变率曲线形态与正常对照组相似。DHF患者左室同一水平不同节段间SRs差异无统计学意义(P>0.05)。③DHF组所有节段SRs均较正常对照组相应室壁节段SRs低,部分节段减低明显,差异有统计学意义(P<0.05)。SHF患者所有节段SRs显著低于正常受检者及DHF患者(P<0.01)。第二部分二维超声斑点追踪技术评价舒张性心力衰竭患者左室内、外膜层心肌功能应用2D-STI技术观测DHF患者左室内、外膜层心肌旋转运动规律及角度峰值,评价DHF患者内、外膜层心肌收缩功能。结果显示:①所有受检者左室同一水平内、外膜层心肌旋转运动方向相同。心尖水平呈逆时针方向旋转,基底水平呈顺时针方向旋转。②心尖水平及基底水平内膜层心肌旋转角度均大于外膜层心肌旋转角度。③与正常对照组相比,DHF及SHF患者心尖水平内膜层心肌旋转角度减低(DHF:5.63±2.20°,SHF:3.01±1.34°,正常:6.69±2.97°,P<0.001);DHF患者心尖水平外膜层心肌旋转角度较正常对照组外膜层心肌旋转角度值减低,但差异无统计学意义。SHF组较正常组及DHF组明显减低。④DHF组基底水平内、外膜层心肌旋转角度与正常对照组相应心肌层旋转角度比较未见明显异常,差异无统计学意义;SHF患者基底水平内、外膜层心肌旋转角度较正常组及DHF组患者显著减低。结论:①DHF患者左室各节段径向应变率曲线形态与正常对照组相似,同一水平不同节段间SRs无明差异。②左室同一水平内、外膜层心肌旋转运动方向相同;心尖水平及基底水平内膜层心肌旋转运动均大于外膜层心肌旋转运动;心尖水平内外膜层心肌旋转运动大于基底水平心肌旋转运动。③DHF组节段性室壁SRs及心尖水平内膜层心肌旋转运动减低,射血分数正常的DHF患者局部心肌收缩功能受损。更多还原

【Abstract】 BACKGROUND Diastolic heart failure(DHF) is a clinical syndrome characterized by the symptoms and signs of heart failure, a preserved ejection fraction (EF), and abnormal diastolic function. Epidemiology investigation shows that about 38%-50% of patients with congestive heart failure are DHF. The mortality and morbidity of DHF is very high. It can be similar to those with systolic heart failure, but the prognosis of DHF is more favorable than systolic heart failure (SHF). Although it is still controversial whether left ventricular (LV) systolic properties are reduced or not, these patients maintain a normal stroke volume and EF at rest. The underlying mechanisms accounting for a normal EF in this group have not been well delineated. Myocardial deformation and LV twist play an important role in cardiac contraction and relaxation. The newly developed two dimensional speckle tracking imaging (2D-STI) technique has presented us with the possibility of enhancing the accuracy of displacement estimation, which was successfully applied to the measurement of myocardial deformation and rotation. Specifically, myocardial deformation in the longitudinal, radial, and circumferential directions can be quantified, and LV twist can be measured. Therefore, we undertook this study to observe the left ventricular segmental peak systolic radial strain rate(SRr)and the characteristics of endocardial and epidcardial rotation by two-dimensional speckle tracking imaging, and to examine myocardial systolic performance in diastolic heart failure patients with a normal left ventricular ejection fraction, and elucidate the contributing mechanisms for a normal EF in patients with DHF. Part 1 Evaluation of left ventricular regional systolic function in DHF patients by two-dimensional speckle tracking imagingThe purpose of this part is to observe the peak value of systolic radial strain (SRr)rate about segmental left ventricular by two-dimensional speckle tracking imaging(2D-STI), and to evaluate the systolic performance in diastolic heart failure patients(DHF)with normal left ventricular ejection fraction. 32 DHF patients, 20 SHF patients and 32 normal subjects were enrolled in this study. Results:①In all the subjects, the curve character of SRr was similar.②There was no significant difference in SRr between different segments at the same level in both DHF patients and healthy subjects.③All segments SRr were lower in both heart failure groups than in controls, but several segments were depressed to a larger extent in DHF patients, and all segments in SHF patients were reduced significantly than in those with DHF.Part 2 Evaluation the difference of rotation between endocardium and epidcardium in DHF patients by two-dimensional speckle tracking imagingThe objective of this part is to assess the characteristics of endocardial and epidcardial rotation and evaluate the different rotation in DHF patients. Results:①In all the subjects, the rotation of the endocardium was obviously greater than that of epicardium.②As seen from the apex, LV endocardium and epicardium performed a wringing motion with a clockwise rotation at the base and countclockwise rotation at the apex.③In the apical plane, endocardial rotation was significantly lower in both heart failure groups than that in controls, and was depressed to a larger extent in SHF patients than in those with DHF (control: 6.69±2.97°, DHF: 5.63±2.20°, SHF: 3.01±1.34°, P<0.001). Epicardial rotation has no significant difference between the DHF group and the control group, though it was significantly lower in patients with SHF.④At the base, the rotation of endocardium and epicardium were not different between DHF and control groups,but it was significantly reduced in patients with systolic heart failure.Conclusions①In all the subjects, the curve character of SRr was similar. There was no significant difference in SRr among different segments at the same level in both DHF patients and healthy subjects.②In all the subjects, the rotation of the endocardium was obviously greater than that of epicardium. LV endocardium and epicardium performed a wringing motion with a clockwise rotation at the base and countclockwise rotation at the apex.③SRr of all segments were lower in both heart failure groups than in controls, but several segments were depressed to a larger extent in DHF patients. In the apical plane, endocardial rotation was significantly lower in DHF patients. The rotation of endocardium and epicardium in the basal and the epicardial rotation were not different between DHF and control groups. Although LV ejection fraction in DHF patients was normal, the systolic function is impaired in DHF patients.更多还原