Hecht H S, DeBord L, Sotomayor N, Shaw R, Ryan C
San Francisco Heart Institute, Seton Medical Center, Daly City, California 94015.
J Am Coll Cardiol. 1994 Feb;23(2):369-76. doi: 10.1016/0735-1097(94)90422-7.
The objectives of this study were 1) to determine the relationship between the amount of exercise-induced ischemic myocardium and the presence or absence of chest pain and ST segment depression, and 2) to define the incidence and characteristics of "truly silent ischemia," that is, ischemia that is not manifested by symptoms or electrocardiographic (ECG) findings.
There are no prior data relating ischemia to chest pain and ST depression. Thallium-201 imaging studies have evaluated perfusion but not ischemia. In contrast, supine bicycle stress echocardiography demonstrates exercise-induced ischemic dysfunction.
Supine bicycle stress echocardiography and arteriography were performed in 130 patients and the severity and geographic extent of ischemic myocardium were compared in three groups. On exercise, Group I patients had both chest pain and ST segment depression (symptomatic ischemia), Group II patients ST depression without chest pain (asymptomatic ischemia) and Group III patients had neither chest pain nor ST depression (truly silent ischemia).
There were no differences among groups in arteriographic characteristics. The incidence of "truly silent ischemia" was 43%. The number of abnormally contracting ischemic segments, average score per segment and sum of scores were virtually identical in Groups I and II and significantly greater than in Group III for the patients (p < 0.01 to < 0.0001), for the vessels as a group (p < 0.01 to < 0.0001) and for the left anterior descending (p < 0.01 to < 0.0001) and right (p < 0.05) coronary arteries. By multivariate analysis, positive findings on the stress ECG was the single most significant variable in relation to the amount of ischemia (p < 0.001); exercise chest pain had no significant relationship.
Exercise-induced ST segment depression is the single most significant variable in relation to the amount of ischemic myocardium; exercise-induced chest pain is not related to the amount of ischemia. Patients with "truly silent ischemia" constitute almost 50% of patients with coronary artery disease and have less ischemia than do patients with ECG indications of ischemia, with or without chest pain.
本研究的目的是：1）确定运动诱发的缺血心肌量与胸痛及ST段压低的有无之间的关系；2）明确“真正无症状性缺血”的发生率及特征，即未表现为症状或心电图（ECG）改变的缺血。
既往尚无关于缺血与胸痛及ST段压低关系的数据。铊-201显像研究评估的是灌注而非缺血。相比之下，仰卧位踏车负荷超声心动图可显示运动诱发的缺血性功能障碍。
对130例患者进行了仰卧位踏车负荷超声心动图和血管造影检查，并比较了三组患者缺血心肌的严重程度和范围。运动时，第一组患者既有胸痛又有ST段压低（有症状性缺血），第二组患者有ST段压低但无胸痛（无症状性缺血），第三组患者既无胸痛也无ST段压低（真正无症状性缺血）。
三组患者的血管造影特征无差异。“真正无症状性缺血”的发生率为43%。异常收缩的缺血节段数量、每个节段的平均评分及评分总和在第一组和第二组患者中几乎相同，且显著高于第三组患者（患者层面，p<0.01至<0.0001；血管组层面，p<0.01至<0.0001；左前降支，p<0.01至<0.0001；右冠状动脉，p<0.05）。多因素分析显示，负荷ECG的阳性结果是与缺血量相关的唯一最重要变量（p<0.001）；运动性胸痛与之无显著关系。
运动诱发的ST段压低是与缺血心肌量相关的唯一最重要变量；运动诱发的胸痛与缺血量无关。“真正无症状性缺血”患者几乎占冠心病患者的50%，且与有或无胸痛的ECG显示有缺血的患者相比，其缺血程度较轻。
