三维斑点追踪技术评价正常成人左房功能的初步研究

目的：探讨三维斑点追踪技术(Three-dimensional speckle tracking imaging, 3D-STI)评价正常成人左房功能的应用价值。方法：选取健康志愿者共104例,按年龄分为青年组(年龄18~44岁)、中年组(年龄45~59岁)和老年组(年龄≥60岁)。采集心脏全容积图像并应用3D-STI软件脱机分析,获取左房容积曲线,得到左房最大容积(LAVmax)、最小容积(LAVmin)及收缩前容积(LAVpre)。计算出左房总排空容积LAVt、总排空分数LATEF、扩张指数EI、被动排空容积LAVp、被动排空分数LAPEF、主动排空容积LAVa、主动排空分数LAAEF、被动排空容积占总排空容积比率PE、主动排空容积占总排空容积比率,以上数据均用体表面积(BSA)标化。以上指标分别反映：(1)存储器功能： LAVmaxi、LAVmini、LAVprei 、LAVti、LATEF、EI；(2)管道功能：LAVpi、LAPEF 、PE(3)助力泵功能：LAVai、LAAEF 、AE。结果： 1、存储器功能指标：LAVmaxi、LAVprei、LAVmini、LAVti随年龄逐渐增大,三组间比较均有统计学意义(P＜0.05)；LATEF、EI三组间无显著差异(P＞0.05)；2、管道功能指标：与青、中年组相比,老年组LAVpi增大(P＜0.05)；中、老年组均较青年组LAPEF 、PE减低(P＜0.05)；4、助力泵功能指标：LAVai 、LAAEF随年龄增加而增大(P＜0.05)；中、老年组均较青年组AE增大(P＜0.05)。结论：三维斑点追踪技术可用于检测不同年龄段正常成人的左房容积及功能的变化规律,可能为临床监测左房功能改变和发现亚临床心血管疾病提供一种可靠的辅助手段。

Assessment of left atrial function in healthy subjects using three-dimensional speckle tracking imaging

ABSTRACT Objective: To discuss the value of the three-dimensional speckle tracking imaging in evaluation of the left atrial function in normal adults. Methods: 104 volunteers were divided into adolescence, middle-aged and elderly groups according to age. Acquired full volume cardiac images and applied 3D-STI off-line analysis software to get the time-volume curve of left atrium, then got left atrial maximum volume(LAVmax), left atrial pre-systole volume(LAVpre), left atrial minimum volume(LAVmin) and calculated left atrial total emptying volume(LAVt=LAVmaxi-LAVmin), left atrial total emptying fraction(LATEF=100%×LAVt/LAVmax), left atrial expansion index(EI= 100%×LAVt /LAVmin), left atrial passive emptying volume(LAVp=LAVmaxi-LAVpre), left atrial passive emptying fraction(LAPEF=100%×LAVp/LAVmax), left atrial active emptying volume(LAVa)=LAVprei-LAVmin), left atrial active emptying fraction(LAAEF=100%×LAVa/LAVpre), the passive emptying percentage of total emptying(PE=LAVp/LAVt), active emptying percentage of total emptying(AE=LAVa/LAVt). All the parameters were standardized by BSA. Of the above parameters, LAVmaxi, LAVprei, LAVmini, LAVti, LATEF and EI represent reservoir function; LAVpi, LAPEF and PE represent conduit function; while LAVai, LAAEF and AE represent booster pump function of the left atrum in heart cycle respectively. Results: 1. Reservoir function index: LAVmaxi, LAVprei, LAVmini and LAVti increased with increasing age(P<0.05); there was no significant difference in LATEF and EI among the three groups(P>0.05). 2. Conduct function index: the LAVpi increased in elderly group when compared with the adolescence and middle-aged groups(p<0.05),but there was no significant difference in the later two groups(P>0.05); Compared to the adolescence group, LAPEF and PE decreased in the middle-aged and elderly groups(P<0.05), while there was no statistical difference between the later two groups(P>0.05).3. booster pump function index: From the adolescence to the elderly group, LAVai and LAAEF increased significantly(P<0.05); Compared to the adolescence group, the AE increased in middle-aged and elderly group(P<0.05),while the difference between the later two groups was not significant(P>0.05). Conclusion: Three-dimensional speckle tracking imaging can be used to detect changes of left atrial volume and function in normal adults of different age, providing a reliable means for monitoring the early changes of left atrial function and subclinical cardiovascular disease.