Lee D D, Kimura S, DeQuattro V
University of Southern California School of Medicine, Los Angeles.
Lancet. 1989 Feb 25;1(8635):403-6. doi: 10.1016/s0140-6736(89)90002-0.
30 patients (10 normotensive, 20 hypertensive) with stable angina and positive treadmill exercise tests entered a double-blind, placebo-controlled crossover trial of metoprolol, 100 mg twice daily. At the end of each treatment phase, blood pressure was monitored for 24 h and Holter and real-time electrocardiographic (ECG) monitoring were carried out and an activity diary kept for 48 h. Blood samples for catecholamine measurement were taken after 30 min supine, 60 min standing, and at the first silent ischaemic event, triggered by the real-time ECG monitor, by means of an ambulatory blood withdrawal pump. Metoprolol lowered blood pressure and heart rate in both normotensive and hypertensive subjects, and reduced the frequency and duration of silent ischaemic episodes in hypertensive subjects. Plasma noradrenaline measured during silent ischaemia while the patients were resting was significantly higher than the control supine level without ischaemia. These findings suggest that noradrenergic hyperactivity may have a role in coronary vasoconstriction and that treatment which neutralizes sympathetic tone may be especially beneficial in treatment of silent ischaemia in hypertensive patients.
30例稳定型心绞痛且平板运动试验阳性的患者（10例血压正常，20例高血压）进入一项美托洛尔的双盲、安慰剂对照交叉试验，美托洛尔剂量为每日2次，每次100mg。在每个治疗阶段结束时，监测24小时血压，进行动态心电图和实时心电图（ECG）监测，并记录48小时活动日记。通过动态抽血泵，在仰卧30分钟、站立60分钟以及实时心电图监测触发的首次无症状缺血事件发生时采集血样用于儿茶酚胺测定。美托洛尔可降低血压正常和高血压受试者的血压及心率，并减少高血压受试者无症状缺血发作的频率和持续时间。在无症状缺血期间患者静息时测得的血浆去甲肾上腺素水平显著高于无缺血的对照仰卧位水平。这些发现提示，去甲肾上腺素能活性亢进可能在冠状动脉收缩中起作用，而中和交感神经张力的治疗可能对高血压患者无症状缺血的治疗特别有益。
