【摘要】 目的对运动负荷5 min后的患者,用舒张期应变超声心动图法检测心肌缺血引起的左室舒张功能碍障,客观的判定局部心肌缺血。方法对37例怀疑缺血性心脏病患者(平均年龄65岁±9岁),在运动负荷前及负荷5 min后,分别在心尖部长轴切面,四腔心切面及二腔心切面的各室壁中间段合计6个左室节段上获取应变曲线。在各节段中,测定主动脉瓣关闭时应变值(A)及舒张期1/3时刻的应变值(B),从而计算出舒张应变指数(Strain diastlic inedx,简称SDI)SDI=A-B/A×100%,再计算出能反映运动负荷前后舒张应变指数变化的运动负荷前后SDI比,以运动负荷心肌同位素扫描所显示冠状动脉所支配心肌缺血的部位做为判定比较基准,根据运动负荷前后SDI比,探讨心肌缺血。结果在37例患者心肌的222节段中,应用运动负荷超声心动图法,检测出163个非缺血节段,59个缺血节段,与运动负荷心肌同位素扫描比较结果相一致,其中:非缺血163个节段负荷前后SDI无显著的差异,而缺血59个节段负荷前后SDI值有显著性差异,非缺血163个节段与缺血59个节段之间,运动负荷前后SDI有显著性差异,与运动负荷同位素相对照后,运动负荷前后SDI比的临界值为0.51时,敏感度为91%,特异性为89%,用此方法可以判定心肌缺血。结论应用舒张期应变超声心动图法在患者运动负荷5 min后,能检测到由于心肌缺血所产生的局部舒张期功能障碍,并判定心肌缺血。更多还原

【Abstract】 Objective Application diastolic strain echocardiography methods to objective determine regional myocardial ischemia.Methods 37 patients with suspected coronary artery disease(CAD) were enrolled.Strain echocardiographic images were acquired at mid segments of all the six left ventricular walls before and 5 minutes after exercise in the apical long axis,two-chamber and four-chamber views.Strain curves were obtained at each segment and peak values of strain at the closure of aortic valve(A) and at one third of diastolic duration(B) were measured.Strain diastolic index(SDI) was calculated as(A-B)/ A×100%.The ratio of SDI before exercise to that after exercise was defined as SDI ratio and compared with exercise SPECT as reference standard to detect myocardial ischemia.Results A total of 222 segments were evaluated by strain echocardiography.So as the results of exercise SPECT,163 segments were classified as non-ischemic segments;59 as ischemic segments.In ischemic segments,there were significant decreases of SDI from before to after exercise,whereas there were no significant differences of SDI from before to after exercise in non-ischemic segments.SDI ratio was significantly decreased in ischemic segments,but not in non-ischemic segments.Based upon the results of exercise SPECT,with a cutoff value of 0.51,SDI ratio yielded a sensitivity of 91% and a specificity of 89% to detect myocardial ischemia in the receiver-operating-characteristics.Conclusion Diastole strain echocardiography provides quantitative assessment of myocardial ischemia by detecting post-ischemic regional LV delayed relaxation even 5 minutes after exercise.更多还原