大鼠在体心肌短暂缺血不同时间对再灌注心律失常的影响

Effects of duration on reperfusion-induced arrhythmia in rat hearts in vivo

[目的]探讨大鼠在体心肌短暂缺血不同时间后出现再灌注心律失常的变化。[方法]Wistar大鼠60只，随机分为6组。分别结扎冠状动脉左前降支0、5、10、15、30、60min后，再灌注45min，连续监测从缺血前至再灌注后45min的心电图变化。取心肌组织测丙二醛（MDA）及超氧化物歧化酶（SOD）含量的变化。[结果]冠状动脉缺血7～10min有心律失常的发生，为室早、室速、室颤。可自愈。再灌注期：缺血5min组，再灌注后室早发生率20％；缺血10min组，再灌注后室速发生率为100％，室颤发生率100％；缺血15min组，再灌注后室早发生率80％，室速发生率40％，无室颤；缺血30min组，再灌注后室旱发生率40％；缺血60min组，无再灌注心律失常。随缺血时间的延长，MDA逐渐增高，SOD逐渐下降（P〈0．05）。[结论]再灌注心律失常与缺血持续时间呈“钟”型分布，氧自由基在再灌注心律失常中不起重要作用。

[Objective] To investigate the effects of different duration of myocardial ischemia on the severity of reperfusion - induced arrhythmias in rat hearts in vivo. [ Methods] Adult Wistar rats were randomly divided into six groups. The left anterior coronary descending branch was ligated in 0 min,5 min,10 min,15 min,30 min,60 min respectively, then the ligating was removed and perfusion was restored in 45 min. The ECG changes were recorded incessantly during myocardial ischemia to reperfusion. Myocardial tissue of infarcted zone was scissor to measure malondialdehyde（MDA） content and superoxide- dismutase（SOD） content. [ Result ] The occurrence rate of reperfusion arrhythmias was that, ventricular premature（VP） 20% after 5 min regional ischemia following 45 min reperfusion; ventricular tachycardia（VT） and ventricular fibrillation （VF） were all 100% after 10min regional ischemia following 45 min reperfusion; VP 80% and VT 40% after 15 min regional ischemia following 45 min reperfusion; VP 40% after 30min regional ischemia following 45 min reperfusion, None of reperfusion arrhythmia occur after 60min ligating of coronary artery in rat. With the ischemia duration prolonged, production of MDA was increased and SOD was decreased. [ Conclusion] The relationship between the duration of myocardial ischemia and reperfusion arrhythmia is the style of ＂bell＂. Free oxygen radicals are not the most important to reperfusion - induced arrhythmia.