Watanabe T, Harumi K, Akutsu Y, Yamanaka H, Okazaki O, Michihata T, Katagiri T
Third Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan.
Jpn Heart J. 1997 Mar;38(2):207-18. doi: 10.1536/ihj.38.207.
Exercise-induced downsloping ST-segment depression is a common manifestation of severe myocardial ischemia. Although greater downsloping ST-segment depression is suspected to indicate more severe ischemia, its exact relationship to regional myocardial blood flow (RMBF) has not yet been clarified. We investigated the relationship between the magnitude of downsloping ST-segment depression and exercise-induced changes in RMBF and collateral perfusion. Nitrogen-13 ammonia positron emission tomography was performed in 6 healthy volunteers and 72 patients with angiographically proven coronary artery disease. The left ventricle was divided into 11 regions of interest, and RMBF in each region was measured at rest and during low-level supine bicycle exercise. Downsloping ST-segment depression of 0.1 mV or more at 80 milliseconds after the J point was accepted as significant. Low-level exercise induced downsloping depression of 0.1 to 0.2 mV in 10 patients (group D1) and downsloping depression of 0.2 mV or more in 8 patients (group D2). Multivessel disease was common in both group D1 (80% of patients) and group D2 (88% of patients). Collateral circulation was significantly more frequent in group D1 (90%) than in group D2 (13%, p < 0.01). Ischemic areas were larger and cardiac function was worse in group D2 than in group D1. The RMBF increased sufficiently in all regions (56 +/- 30%) with exercise in the healthy group. In group D1, RMBF was unchanged or decreased in ischemic areas (10 +/- 23%) but increased sufficiently in surrounding areas (50 +/- 32%). In group D2, RMBF was unchanged in ischemic areas (17 +/- 24%) and increased insufficiently in surrounding areas (41 +/- 21%). Therefore, exercise-induced downsloping ST-segment depression of 0.1 to 0.2 mV may reflect an underlying change in blood flow in viable myocardium with collateral perfusion, and downsloping depression of 0.2 mV or more may reflect more severely impaired myocardium without collateral perfusion.
运动诱发的ST段下斜型压低是严重心肌缺血的常见表现。尽管更大程度的ST段下斜型压低被怀疑提示更严重的缺血，但其与局部心肌血流量（RMBF）的确切关系尚未阐明。我们研究了ST段下斜型压低的程度与运动诱发的RMBF及侧支循环灌注变化之间的关系。对6名健康志愿者和72例经血管造影证实患有冠状动脉疾病的患者进行了氮-13氨正电子发射断层扫描。将左心室分为11个感兴趣区，在静息状态和低水平仰卧位自行车运动期间测量每个区域的RMBF。J点后80毫秒时ST段下斜型压低0.1 mV或更多被视为有意义。低水平运动使10例患者（D1组）出现0.1至0.2 mV的ST段下斜型压低，8例患者（D2组）出现0.2 mV或更多的ST段下斜型压低。多支血管病变在D1组（80%的患者）和D2组（88%的患者）中都很常见。D1组（90%）的侧支循环明显比D2组（13%，p<0.01）更常见。D2组的缺血区域比D1组更大，心脏功能更差。健康组所有区域的RMBF在运动时均充分增加（56±30%）。在D1组，缺血区域的RMBF无变化或减少（10±23%），但周围区域充分增加（50±32%）。在D2组，缺血区域的RMBF无变化（17±24%），周围区域增加不足（41±21%）。因此，运动诱发的0.1至0.2 mV的ST段下斜型压低可能反映了有侧支循环灌注的存活心肌血流的潜在变化，而0.2 mV或更多的下斜型压低可能反映了无侧支循环灌注的更严重受损的心肌。
