Herlitz J, Elmfeldt D, Hjalmarson A, Holmberg S, Málek I, Nyberg G, Rydén L, Swedberg K, Vedin A, Waagstein F, Waldenström A, Waldenström J, Wedel H, Wilhelmsen L, Wilhelmsson C
Am J Cardiol. 1983 May 1;51(8):1282-8. doi: 10.1016/0002-9149(83)90299-0.
In a double-blind randomized trial, 1,395 patients with suspected acute myocardial infarction (MI) were investigated to evaluate the possibility of limiting indirect signs of the size and severity of acute MI with the beta 1-selective adrenoceptor antagonist metoprolol. Metoprolol (15 mg) was given intravenously and followed by oral administration for 3 months (200 mg daily). Placebo was given in the same way. The size of the MI was estimated by heat-stable lactate dehydrogenase (LD[EC 1.1.1.27]) analyses and precordial electrocardiographic mapping. Lower maximal enzyme activities compared with placebo were seen in the metoprolol group (11.1 +/- 0.5 mukat X liter-1) when the patient was treated within 12 hours of the onset of pain (13.3 +/- 0.6 mukat X liter-1; n = 936; p = 0.009). When treatment was started later than 12 hours, no difference was found between the 2 groups. Enzyme analyses were performed in all but 20 patients (n = 1,375). Precordial mapping with 24 chest electrodes was performed in patients with anterior wall MI. The final total R-wave amplitude was higher and the final total Q-wave amplitude lower in the metoprolol group than in the placebo group. Patients treated with metoprolol less than or equal to 12 hours also showed a decreased need for furosemide, a shortened hospital stay, and a significantly reduced 1-year mortality compared with the placebo group, whereas no difference was observed among patients treated later on. After 3 months, however, there was a similar reduction in mortality among patients in whom therapy was started less than or equal to 12 hours and greater than 12 hours after the onset of pain. The results support the hypothesis that intravenous metoprolol followed by oral treatment early in the course of suspected myocardial infarction can limit infarct size and improve long-term prognosis.
在一项双盲随机试验中，对1395例疑似急性心肌梗死（MI）患者进行了研究，以评估使用β1选择性肾上腺素能受体拮抗剂美托洛尔限制急性心肌梗死面积和严重程度间接征象的可能性。静脉注射美托洛尔（15mg），随后口服给药3个月（每日200mg）。安慰剂以相同方式给药。通过热稳定乳酸脱氢酶（LD[EC 1.1.1.27]）分析和胸前心电图标测来估计心肌梗死面积。当患者在疼痛发作后12小时内接受治疗时，美托洛尔组的最大酶活性低于安慰剂组（11.1±0.5微卡/升）（13.3±0.6微卡/升；n = 936；p = 0.009）。当治疗开始时间晚于12小时时，两组之间未发现差异。除20例患者外（n = 1375），对所有患者均进行了酶分析。对前壁心肌梗死患者进行了24个胸电极的胸前标测。美托洛尔组的最终总R波振幅较高，最终总Q波振幅较低。与安慰剂组相比，在疼痛发作后12小时内或更短时间接受美托洛尔治疗的患者还显示出对速尿的需求减少、住院时间缩短以及1年死亡率显著降低，而在较晚接受治疗的患者中未观察到差异。然而，3个月后，在疼痛发作后12小时内或更短时间开始治疗的患者与12小时后开始治疗的患者之间，死亡率有类似程度的降低。结果支持这样的假设，即在疑似心肌梗死病程早期静脉注射美托洛尔后进行口服治疗可限制梗死面积并改善长期预后。
