法乐四联症右室流出道心肌超微结构特点及其临床意义

Ultrastructural characteristic of myocardium in right ventricular outflow tract with tetralogy of Fallot and its clinical significance

目的研究不同年龄组法乐四联症(TOF)右室流出道心肌超微结构特点。方法取31例TOF右室流出道心肌组织,按年龄分为1岁以下组、1～3岁组和3岁以上组,取12例其他心脏病患者右室流出道心肌作为对照组,分别用光学显微镜和透射电镜对心肌组织进行超微结构的观察。结果1～3岁TOF组和3岁以上TOF组心肌肌原纤维排列方向紊乱,同向性丧失,大量小线粒体增生堆积,分布不均匀,基质密度增加,Z线粗细不等、缺失、断裂；1岁以下TOF组超微结构改变较轻微。对照组可见心肌结构正常。结论TOF右室流出道存在许多心肌超微结构异常的心肌细胞,TOF病人应尽量在1岁以内进行手术,可避免心肌超微结构变化对心功能的不良影响。

Objective To study the ultrastructural characteristic of myocardium in the right ventricular outflow tract with tetralogy of Fallot （TOF） in different age groups and elucidate its clinical significance. Methods Total 31 patients with TOF aged 3 months to 25 years were selected as study groups and divided into 3 groups：group 1,11 patients,ranging in age from 3 months to 1 year; group 2,7 patients, ranging in age from 1 to 3 years;group 3,13 patients, ranging in age from 3 to 25 years. Twelve patients with small artrial or ventricular septal defect served as control group. Material of intraoperative biopsies of the right ventricular myocardium of all 31 patients was studied under both light and electron microscopies. Results In study groups,the sarcolemma often formed pouches filled with abnormal mitochondria and the myocardial fibers presented a disoriented arrangement. In addition, the myofibrils had the thickened Z band,appearance of hypercontraction and even lost the normal structures. The ultrastructural alteration of myocardium became more severe after 1 year old than ever. Conclusion Many ultrastructural changes of right ventricular myocardium in patients with TOF correlated with age cart be observed. It is suggested that surgical treatment of TOF should be achieved as early as possible.