心肌做功指数评价模拟失重对成人右心功能的影响

Effects of Simulated Weightlessness on Adult's Right Heart Function Assessed with Tei Index

目的用超声心动图心肌做功指数(Tei)探讨模拟失重对健康成人右心功能的影响。方法健康青年男性志愿者12名,21 d-6°头低位卧床模拟失重。分别于卧床前、卧床第10,20天行心脏彩超检查,记录心尖四腔切面组织多普勒图像,应用定量组织速度成像(QTVI)技术,脱机测量右房室环处等容收缩期(IVCT)、射血期(ST)及等容舒张期(IVRT),计算Tei。结果模拟失重10,20 d组与对照组比较,右室Tei均显著增大(P<0.01),IVCT缩短。模拟失重10 d组和20 d组比,右室Tei和IVCT无显著变化。模拟失重第10天,与对照组比IVRT无明显变化;模拟失重第20天,与对照组比,IVRT延长,差异具有显著性(P<0.05)。3组间IVCT无显著性差异。结论 Tei指数可定量评价失重状态下的右心功能下降。

Objective To elucidate the influence of simulated weightlessness on adult＇ s right heart function with Tei index obtained by echocardiography. Methods Twelve young-male subjects suffered simulated weight- lessness condition with continuous -6°head-down tilt bed rest（HDBR） for 21 d . Echocardiographic tissue Doppler figures were gotten from apical four-chamber view at the beginning, and on the 10th day and 20th day of the experiment. The technique of quantitative tissue velocity imaging was adopted to measure isovolumic contraction time（IVCT）, isovolumic relaxation time（IVRT） and systolic time（ST） at right atrioventricular ring, then the Tel index of right ventricle were calculated. Results Tel index of right heart increased signifi- cantly in the 10th day and 20th day group as compared with control group （P 〈 0.01 ）, however, IVCT de- creased. Tei index and IVCT in right heart of the 10th day group didn＇ t change remarkablely as compared with that of the 20th day group. On the 10th day, no remarkable change appeared in IVRT, while on the 20th day, IVRT of right ventricle prolonged significantly（P 〈0.05 ）. There was no significant difference in IVCT among groups. Conclusions Tel index can be used to assess quantitatively the effects of weightlessness simula- tion on fight heart function.