Picano E, Pogliani M, Lattanzi F, Distante A, L'Abbate A
CNR Institute of Clinical Physiology, Pisa, Italy.
Am J Cardiol. 1989 Jan 1;63(1):14-6. doi: 10.1016/0002-9149(89)91067-9.
Exercise-induced ischemia is generally attributed to an increase in myocardial demand in the presence of coronary stenosis limiting flow supply. An additional mechanism--the occurrence of coronary steal due to excessive endogenous adenosine release--has also been hypothesized. The effect of adenosine receptor blocking by aminophylline in effort ischemia was tested in 8 patients with stable effort-induced angina pectoris, reproducible positive exercise stress tests and angiographically assessed coronary artery disease. Following double-blind, randomized intravenous infusion of aminophylline (3 mg/kg over 3 minutes) or placebo (20 ml of saline over 3 minutes), the patients underwent upright bicycle exercise stress tests on 2 consecutive days. After aminophylline, there was an increase in work tolerance (aminophylline 7.5 +/- 1.8 minutes of exercise vs placebo 5.4 +/- 1.5 minutes; p less than 0.05). There was a parallel increase in the ischemic threshold, evaluated with the rate-pressure product (mm Hg X beats/min X 100(-2)) at 0.1 mV of ST-segment depression (221 +/- 35 vs 184 +/- 20; p less than 0.01). Thus, at a dosage that should effectively inhibit adenosine receptors, aminophylline infusion exerts a beneficial effect on exercise-induced ischemia, possibly through the prevention of myocardial flow maldistribution elicited by excessive adenosine release during effort.
运动诱发的局部缺血通常归因于在冠状动脉狭窄限制血流供应的情况下心肌需求增加。另外一种机制——即由于内源性腺苷过度释放导致的冠状动脉窃血现象——也已被提出。在8例稳定型运动诱发心绞痛、运动应激试验结果可重复且经血管造影评估患有冠状动脉疾病的患者中，测试了氨茶碱阻断腺苷受体对劳力性局部缺血的影响。在双盲、随机静脉输注氨茶碱（3分钟内输注3mg/kg）或安慰剂（3分钟内输注20ml生理盐水）后，患者连续2天进行直立位自行车运动应激试验。输注氨茶碱后，运动耐量增加（氨茶碱组运动7.5±1.8分钟，安慰剂组运动5.4±1.5分钟；p<0.05）。以ST段压低0.1mV时的速率-压力乘积（mmHg×心跳次数/分钟×100⁻²）评估的缺血阈值也有相应增加（分别为221±35和184±20；p<0.01）。因此，在能有效抑制腺苷受体的剂量下，输注氨茶碱对运动诱发的局部缺血有有益作用，可能是通过防止运动期间内源性腺苷过度释放引起的心肌血流分布不均来实现的。
