Nyberg G, Bjurö T, Hagman M, Smith U
Acta Med Scand Suppl. 1981;644:30-3. doi: 10.1111/j.0954-6820.1981.tb03114.x.
The bicycle exercise tolerance was studied in ten patients with angina pectoris after one week's treatment with an alpha-beta-blocker (labetalol 300 mg b.d.), alpha-beta-blocker (propranolol 80 mg b.d.) and placebo. The ST-segment of the ECG was continuously evaluated by on-line computerized averaging of complexes which greatly reduces noise and eliminate artefacts caused by varying baseline. Blood pressure was lowest with labetalol and heart rate lowest with labetalol and of heart rate during exercise was equally well depressed by both drugs. They also attenuated ST-depression at a given load but enhanced ST-depression for a given heart rate. At heart rate 100/min ST-depression was significantly greater with propranolol than with labetalol. It is concluded that provided ST-depression during treatment with B-blockers is correlated to myocardial ischemia in the same way as without such treatments used, other factors, e.g. an increase in cardiac size, will contribute more to the ischemia. labetalol may cause less increase in cardiac size than propranolol.
对10例心绞痛患者在接受α-β阻滞剂（拉贝洛尔，每日2次，每次300毫克）、α-β阻滞剂（普萘洛尔，每日2次，每次80毫克）和安慰剂治疗1周后进行了自行车运动耐力研究。通过对心电图复合体进行在线计算机平均来持续评估ST段，这大大降低了噪声并消除了由基线变化引起的伪迹。使用拉贝洛尔时血压最低，使用拉贝洛尔时心率最低，两种药物对运动期间心率的抑制作用相当。它们还在给定负荷下减轻了ST段压低，但在给定心率下增强了ST段压低。在心率为100次/分钟时，普萘洛尔引起的ST段压低明显大于拉贝洛尔。结论是，如果β阻滞剂治疗期间的ST段压低与未进行此类治疗时的心肌缺血相关方式相同，那么其他因素，如心脏大小增加，将对缺血的影响更大。拉贝洛尔可能比普萘洛尔引起的心脏大小增加更少。
