应变率成像评价多巴酚丁胺负荷试验中缺血心肌的舒张功能

Evaluation of the diastolic function of ischemic myocardium by strain rate imaging combined with dobutamine stress echocardiography

目的探讨应变率成像(SRI)评价多巴酚丁胺负荷试验(DSE)中缺血心肌的舒张功能变化。方法选取20例冠心病患者和30例健康对照者,测量左心室前壁及前间隔心肌的应变率(SR)指标。结果正常组舒张早期SR随负荷剂量的增加而增大,与静息状态下比较差异有统计学意义(P<0.05)。冠心病组舒张早期SR在小剂量10、20μg.kg-1.min-1时测值增加(P<0.05),大剂量30、40μg.kg-1.min-1时测值降低,与正常组同一负荷阶段相比差异有统计学意义。缺血心肌收缩后收缩的检出率明显高于正常心肌(χ2=6.315,P<0.05)。舒张早期峰值SR在30μg.kg-1.min-1时检测的敏感性和特异性分别为88%和92%。结论缺血心肌的舒张早期峰值SR降低,是反映局部舒张功能变化敏感而特异的指标,收缩后收缩可评价局部心肌舒张功能。

Objective To assess the diastolic function of ischemic myocardium by ultrasonic strain rate imaging （SRI） combined with dobutamine stress echocardiography （DSE）. Methods The peak strain rate （SR） of early and late diastole were respectively measured in 2fl subjects with coronary disease and 30 healthy volunteers on anterior septum and anterior walls. Results In normal group,the early diastolic peak SR values increased while dobutamine dose rise（ P ~0.05）. In coronary disease group, SR values of early diastole increased at low dose （10μg·kg^-1·min^-1 and 20 μg·kg^-1·min^-1, P〈0.05）, while decreased at dose 30 μg·kg^-1·min^-1 and 40μg·kg^-1·min^-1, there was no statistical difference comparing with the rest condition. The post-systolic shortening （PSS） was higher in ischemic myocardium than in normal myocardium（x^2 = 6. 304, P 〈0.05）. The sensitivity and specificity of the early diastolic peak SR at dose 30 μg·kg^-1·min^-1 were 88% and 92% respectively. Conclusions The decreasing of early diastolic peak SR is sensitive and specific for the regional myocardial function evaluation, while the PSS provides a reliable assessment for the regional myocardial function.