Portegies M C, Sijbring P, Göbel E J, Viersma J W, Lie K I
Department of Cardiology, University Hospital Groningen, The Netherlands.
Am J Cardiol. 1994 Dec 1;74(11):1095-8. doi: 10.1016/0002-9149(94)90458-8.
Recent studies strongly support the prognostic importance of transient silent ischemia. Because patients with silent ischemia are at higher risk of a cardiac event, they are likely to benefit not only from control of symptoms, but also from treatment directed at prevention of ischemia. The efficacy of controlled-release metoprolol 200 mg once daily and diltiazem 60 mg 4 times daily was assessed in a randomized, double-blind, crossover study in 32 patients with proven coronary artery disease, predominantly asymptomatic myocardial ischemia, positive bicycle exercise test results, and > or = 5 minutes of asymptomatic ST-segment depression on a 24-hour screening ambulatory electrocardiogram (ECG). At the beginning and at the end of both 3-week treatment periods, an exercise test was performed and a 72-hour ambulatory ECG was recorded. Both active treatment periods were preceded by a 2-week placebo phase. Both treatments effectively reduced and postponed exercise-induced ST depression and reduced the total ischemic integral on the ambulatory ECG. Only metoprolol significantly reduced the mean number of ischemic episodes (54%, p = 0.0003, vs 31% for diltiazem, p = NS) and the mean duration of ischemia (51%, p = 0.012, vs 27% for diltiazem, p = NS) compared with baseline values. Metoprolol strongly blunted the morning and afternoon peak in the circadian distribution of ischemia, whereas diltiazem did not change the circadian distribution of ischemia at all.
近期研究有力地支持了短暂性无症状性心肌缺血在预后方面的重要性。由于无症状性心肌缺血患者发生心脏事件的风险更高，他们不仅可能从症状控制中获益，还可能从针对预防缺血的治疗中获益。在一项随机、双盲、交叉研究中，对32例经证实患有冠状动脉疾病、主要为无症状性心肌缺血、自行车运动试验结果阳性且24小时动态心电图（ECG）显示有≥5分钟无症状性ST段压低的患者，评估了每日一次200毫克控释美托洛尔和每日4次60毫克地尔硫䓬的疗效。在两个为期3周的治疗期开始和结束时，进行运动试验并记录72小时动态心电图。两个积极治疗期之前均有一个为期2周的安慰剂阶段。两种治疗均有效减轻并推迟了运动诱发的ST段压低，并降低了动态心电图上的总缺血积分。与基线值相比，只有美托洛尔显著减少了缺血发作的平均次数（54%，p = 0.0003，地尔硫䓬为31%，p = 无统计学意义）和缺血的平均持续时间（51%，p = 0.012，地尔硫䓬为27%，p = 无统计学意义）。美托洛尔强烈减弱了缺血昼夜分布中的上午和下午高峰，而地尔硫䓬根本没有改变缺血的昼夜分布。
