Pauliks Linda B, Pietra Bill A, Kirby Scott, Logan Loralee, DeGroff Curt G, Boucek Mark M, Valdes-Cruz Lilliam M
Pediatric Cardiology, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA.
J Heart Lung Transplant. 2005 Nov;24(11):1804-13. doi: 10.1016/j.healun.2004.05.032.
Tissue Doppler imaging (TDI), a non-invasive echocardiography technique, permits quantitative analysis of the regional distribution pattern of myocardial velocities. During normal childhood development, regional function changes markedly, including an increasing predominance of longitudinal velocities. This study analyzed the impact of heart transplantation on ventricular mechanics in growing children.
TDI was performed in 30 pediatric heart transplant recipients (7.1 +/- 6.2 years) and 32 age-matched healthy children (6.8 +/- 5.4 years). Patients had no rejection history and were 3.1 years (median) post-transplant. Color TDI images from apical and parasternal views were stored as echocardiographic raw data. Off-line analysis was used to measure peak systolic and diastolic myocardial velocities in 6 basal cardiac segments for longitudinal (anterior, inferior, lateral, septal, right ventricle) and radial velocities (posterior). Isovolumic acceleration, a load-insensitive function marker, was determined as slope of the upstroke of the isovolumic contraction wave. Multiple regression modeling was used for statistics.
Systolic myocardial velocities still increased with age after transplantation, but the velocity distribution pattern was changed. In transplanted hearts, left ventricular longitudinal velocities were lower and radial velocities were higher than in the controls, but isovolumic acceleration was similar. In the right ventricle, longitudinal velocities and isovolumic acceleration were significantly decreased after transplantation. Wall motion abnormalities were present in 50% of patients.
Regional wall motion analysis shows significant alterations of the fundamental biomechanical pump function of the left ventricle after heart transplantation in children, with a shift from longitudinal to radial fibers and depressed right ventricular wall motion. This may have important implications for the long-term graft function required in children.
组织多普勒成像（TDI）是一种非侵入性超声心动图技术，可对心肌速度的区域分布模式进行定量分析。在儿童正常发育过程中，区域功能会发生显著变化，包括纵向速度的优势日益增加。本研究分析了心脏移植对成长中儿童心室力学的影响。
对30名小儿心脏移植受者（7.1±6.2岁）和32名年龄匹配的健康儿童（6.8±5.4岁）进行TDI检查。患者无排斥反应病史，移植后中位时间为3.1年。从心尖和胸骨旁视图获取的彩色TDI图像作为超声心动图原始数据存储。采用离线分析测量6个心脏基底节段的纵向（前壁、下壁、侧壁、间隔、右心室）和径向（后壁）的收缩期和舒张期心肌峰值速度。等容加速度是一种负荷不敏感的功能指标，定义为等容收缩波上升支的斜率。采用多元回归模型进行统计学分析。
移植后收缩期心肌速度仍随年龄增加，但速度分布模式发生改变。在移植心脏中，左心室纵向速度低于对照组，径向速度高于对照组，但等容加速度相似。在右心室，移植后纵向速度和等容加速度显著降低。50%的患者存在室壁运动异常。
区域室壁运动分析显示，儿童心脏移植后左心室基本生物力学泵功能有显著改变，从纵向纤维向径向纤维转变，右心室壁运动减弱。这可能对儿童所需的长期移植物功能具有重要意义。
