镁对缺血再灌注心脏触发性心律失常的抑制作用  

Inhibitory effect of magnesium on triggered arrhythmias of ischemia reperfusion heart

作　　者：朱俏萍[1,2] 赖世忠[1,2] 刘伊丽 黄晓川[1,2] 

机构地区：[1]广州解放军第一五七医院心内科 [2]第一军医大学南方医院心内科

出　　处：《中华心血管病杂志》1997年第5期375-378,共4页Chinese Journal of Cardiology

摘　　要：为进一步探讨镁对缺血再灌注心脏触发性心律失常的作用，本研究利用心外膜接触电极记录兔在体心脏缺血再灌注时单相动作电位的变化，分析触发活动与再灌注性心律失常的关系及镁离子的作用机理。结果显示：再灌注心脏８１．８％在缺血区描记到后去极化波形，再灌注性心律失常的６０．０％与早期后去极化有关。硫酸镁静脉注射１００ｍｇ／ｋｇ后，早期后去极化由６３．６％减少至１８．２％，室性心动过速发生率由５４．４％降至９．１％（Ｐ＜０．０１），单相动作电位振幅下降幅度减少１６．２％。心肌缺血１５分钟及再灌注１０分钟，９０％复极化时程分别缩短２１．３％及２６．１％（Ｐ＜０．０１）。实验表明：（１）再灌注性心律失常的发生与触发活动密切相关。（２）镁对触发活动和室性心律失常有直接的抑制作用，可减轻单相动作电位的衰减，缩短末期复极化时程。The mechanism by which magnesium therapy suppresses ventricular tachyarrhythmias is unknown. Previous studies suggested that magnesium had effects on cesium, ouabain induced triggered activity and ventricular arrhythmias. The present research was to ascertain the role of magnesium on triggered arrhythmias of ischemia reperfusion rabbit heart in vivo. Monophasic action potentials were recorded with contact electrode in the ischemic zone and nonischemic zone. In 22 anesthetized rabbits, 15 minutes of occlusion of left anterior descending coronary artery were followed by reperfusion. Magnesium sulfate 100mg/kg was given by intravenous infusion ( n =11). Early afterdepolarization (EAD), delayed afterdepolarization (DAD), monophasic action potential amplitude (MAPA), monophasic action potential duration 90% (MAPD 90 ) and ventricular arrhythmias during ischemic and reperfusion were analyzed. In 9 of 11 (81.8%) trials, afterdepolarizations developed at the moment of reperfusion, with a mean amplitude of EAD 2.0±0.3 mv and DAD 2.1±0.5 mV. EAD was associated with reperfusion arrhythmias in 6 of 10 (60%) cases. In magnesium sulfate therapy group, EAD decreased from 63.6% to 18.2%. The occurence of ventricular tachycardia decreased from 54.5% to 9.1% ( P < 0.01). MAPA increased 16.2%. After 15 minutes of ischemia and 10 minutes of reperfusion, MAPD 90 shortened 21.3% and 26.1% respectively ( P <0 01). Conclusion: (1) Reperfusion arrhythmias was associated with triggered activity. (2) Magnesium therapy would suppress the triggered activity, the ventricular arrhythmias, increase action potential amplitude, shorten action ptential duration 90%. These may be important mechanisms of magnesium inhibiting ischemia and reperfusion arrhythmias.

关 键 词：心肌缺血 再灌注损伤 心律失常 镁 保护作用 

分 类 号：R972[医药卫生—药品] R541.710.1[医药卫生—药学]