冠状动脉造影正常的心绞痛患者心肌血流分布特征的研究

目的 研究X 综合征患者心房起搏状态下心肌血流分布特征和微血管功能的变化。方法 采用定量心肌超声显像(MCE) 测定25 例X 综合征患者在心房起搏状态下心肌血流分布特征和微血管功能状态的变化。测定前对所有患者进行活动平板运动实验(Bruce 方案), 将运动中出现前壁ST 水平或下斜型压低患者分配在X 综合征组(X 组, 男5 例,女6 例, 平均年龄52 岁), 而无ST 段变化的患者为对照组(男7 例, 女7 例, 平均年龄46 岁)。基础及心房起搏(150 bpm, 共3 min) 后即刻测定前降支区域心内膜和心外膜下心肌灰阶比值(ED/EP)。结果 心房起搏可诱发所有X 综合征患者出现胸痛及ST 段压低, 而对照组则阴性。起搏后即刻X 综合征患者ED/EP 比值显著降低(0.98 ±0.10 ~ 0.76 ±0.17, P <0.01), 而对照组则无变化。结论 运动负荷状态下心肌血流分布异常是导致X 综合征患者出现胸痛和ST 段压低的主要原因。

Characteristics of myocardial blood flow distribution in patients with angina pectoris and normal coronary arteriograms

Aim To evaluate microvascular function and its relation to the genesis of chest pain and S T segment depression during exercise in patients with syndrome X. Methods Changes pacing-induced in transmural myocardial blood f low distribution were quantitatively assessed by 2-dimensional myocardial contrast echocardiog raphy. Myocardial blood flow distribution before and after pacing stress was assessed by measuring the ratio of the endocardial to epicardial gray level (ie, endo/epigray level ratio) in the territory of the left anteior descending coronary. Results Of 25 patients w ith a history of chest pain and normal coronary arteries with the negative ergonovine test, 11 had exercise-induced chest pain and ST segment depression(syndrome X), and 14 did not (controls). Pacing-induced chest pain and ST segment depression were observed in syndrome X, but not in controls. The endo/epigray level ratio in syndrome X significantly decreased after pacing (form 0.98 ±0.10 to 0.76 ±0.17, P <0.01), but not in controls (from 0.97 ±0.08 to 0.99 ±0.08, P >0.05). Conclusion Abnormal myocardial blood flow distribution may play an important role in exercise induced chest pain and ST segment depression in these patients.