应变率显像检测心肌舒张起始时间对多巴酚丁胺负荷试验诱发心肌缺血的诊断价值

Diagnostic value of time to onset of regional relaxation by strain rate imaging in detecting dobutamine-induced cardiac ischemia

目的探讨心肌舒张起始时间（TR）对多巴酚丁胺负荷试验（DSE）所诱发心肌缺血的检测价值。方法选择冠心病患者35例及年龄、性别相匹配的健康志愿者20例,检测静息状态下心肌各节段TR值,冠心病组另行多巴酚丁胺负荷试验并检测最大负荷状态的TR值。结果对照组中间段TR短于心尖段（P〈0.05）及基底段TR（P〉0.05）。冠心病组静息状态运动异常的心肌与对照组比较TR值明显延长（P〈0.01）;DSE过程中各节段心肌TR普遍有所缩短,但非缺血心肌与缺血心肌相比,TR缩短程度差异有统计学意义（32%对18%,P〈0.05）,如果将DSE过程中TR变化率≤20%作为判断心肌缺血的标志,其敏感性90%,特异性78%。结论作为评价局部心肌舒缩功能的指标,TR的检测方便、快捷;DSE过程中TR变化率可以作为判断心肌缺血与否的一个定量指标。

Objective To examine the utility of time to onset of regional relaxation（TR） in patients with inducible ischemia. Methods Resting regional TR was examined in 55 subjects, 20 in control group and 35 in coronary artery disease （CAD） group. Patients in CAD underwent dobutamine stress echocardiography（DSE）, and regional TR was measured at peak dobutamine stress. Results In control group,mean resting TR was shorter in the mid segments compared to apical（ P〈0. 05） and basal segments （ P〈0. 05）. In CAD group, resting ischemic regional TR was significantly prolonged comparison with the same segmental TR in control group（ P〈0.01 ）. There was no statistical difference between the normal segmental TR in CAD group and the same segmental TR in control group. Regional TR in CAD group decrease during DSE, but the percent change in TR during dobutamine stress was significantly higher in normal compared to ischemic segments（32% vs 18%, P〈0.05）. A cutoff of 20% decrease in TR with DSE yielded a sensitivity of 90% and specificity of 78% for dobutamine-induced wall motion abnormality. Conclusions TR is a quantitative index of regional myocardial function with satisfactory feasibility. Percent change in TR may identify ischemic segments during DSE.