Redwood S R, Bashir Y, Huang J, Leatham E W, Kaski J C, Camm A J
Department of Cardiological Sciences, St George's Hospital Medical School, London, U.K.
Eur Heart J. 1997 Aug;18(8):1269-77. doi: 10.1093/oxfordjournals.eurheartj.a015438.
Administration of intravenous magnesium sulphate has been shown to be protective during acute myocardial ischaemia and it may therefore have beneficial effects in unstable angina. The purpose of this study was to assess the effects of a 24-h infusion of magnesium in patients with unstable angina.
Patients who presented with unstable angina with electrocardiographic changes were randomized to receive a 24-h intravenous infusion of magnesium or placebo within 12 h of admission. The primary endpoint was myocardial ischaemia, as assessed by 48 h Holter monitoring. Resting 12-lead ECGs, creatine kinase-MB release and urinary catecholamines were also assessed. Patients were followed for 1 month. Thirty-one patients received magnesium sulphate and 31 placebo. Baseline characteristics and extent of coronary disease were similar in both groups. On 48 h Holter monitoring, 14 patients (50%) had transient ST segment shifts in the magnesium group vs 12 patients (46%) in the placebo group. However, there were fewer ischaemic episodes in the magnesium group (51 vs 101, P < 0.001) and there was a trend towards an increase in the total duration of ischaemia in the placebo group compared to the magnesium group in the second 24 h (2176 min vs 719 min respectively, P = 0.08). Regression of T wave changes on the 24 h ECG occurred more frequently in patients who received magnesium compared to those treated with placebo (11 patients vs 0 patients respectively, P < 0.005). Creatine kinase-MB release was significantly less at 6 and 24 h in patients who received magnesium compared to those treated with placebo. Catecholamine excretion was lower in patients treated with magnesium than in those treated with placebo (adrenaline: 1.05 +/- 0.16 vs 1.61 +/- 0.32 ng.mmol-1 creatinine; noradrenaline: 9.99 +/- 1.82 vs 18.48 +/- 2.41 ng.mmol-1 creatinine respectively in the first 12 h sample, P < 0.05).
Intravenous magnesium reduces ischaemic ECG changes, creatine kinase-MB release and urinary catecholamine excretion in the acute phase of unstable angina. Thus, magnesium may be a beneficial additional therapy for these patients. Further studies are required to confirm these finding.
静脉注射硫酸镁已被证明在急性心肌缺血期间具有保护作用，因此可能对不稳定型心绞痛有益。本研究的目的是评估24小时输注镁对不稳定型心绞痛患者的影响。
出现不稳定型心绞痛且伴有心电图改变的患者在入院12小时内被随机分为接受24小时静脉输注镁或安慰剂。主要终点是通过48小时动态心电图监测评估的心肌缺血。还评估了静息12导联心电图、肌酸激酶-MB释放和尿儿茶酚胺。对患者随访1个月。31例患者接受硫酸镁治疗，31例接受安慰剂治疗。两组的基线特征和冠状动脉疾病程度相似。在48小时动态心电图监测中，镁组有14例患者（50%）出现短暂ST段移位，而安慰剂组为12例患者（46%）。然而，镁组的缺血发作次数较少（51次对101次，P<0.001），并且在第二个24小时内，安慰剂组的缺血总时长有比镁组增加的趋势（分别为2176分钟对719分钟，P=0.08）。与接受安慰剂治疗的患者相比，接受镁治疗的患者在24小时心电图上T波改变的恢复更频繁（分别为11例患者对0例患者，P<0.005）。与接受安慰剂治疗的患者相比，接受镁治疗的患者在6小时和24小时时肌酸激酶-MB释放显著减少。接受镁治疗的患者儿茶酚胺排泄低于接受安慰剂治疗的患者（肾上腺素：在最初12小时样本中分别为1.05±0.16对1.61±0.32纳克·毫摩尔⁻¹肌酐；去甲肾上腺素：分别为9.99±1.82对18.48±2.41纳克·毫摩尔⁻¹肌酐，P<0.05）。
静脉注射镁可减少不稳定型心绞痛急性期的缺血性心电图改变、肌酸激酶-MB释放和尿儿茶酚胺排泄。因此，镁可能是这些患者有益的辅助治疗方法。需要进一步研究来证实这些发现。
