缺血再灌注对在体兔窦房结电生理功能的损伤研究

Effect of ischemia reperfusion on electrophysiological function of sinoatrial node in rabbits

目的 探讨缺血再灌注对在体兔窦房结电生理功能的影响。方法 取家兔 90只随机分为对照组、缺血 10、3 0、60、12 0min组及缺血再灌注 4h组 ,每组 10只。通过结扎及放松右冠状动脉起始部建立在体兔窦房结缺血再灌注损伤模型 ,同步记录体表及心腔内电图 ,观察AA间期变化及心律失常发生情况。结果 ①对照组各时相点AA间期比较均无显著差异 (P >0 .0 5 )。②缺血组与缺血再灌注组 80只兔子在缺血期共有 5 1只 ( 63 .75 %)发生窦性停搏、窦性心动过缓伴不齐、或房性快速性心律失常 ,且随缺血时间延长 ,心律失常发生率增加 ;有 5 4只兔子 (占 67.5 %)于结扎右冠状动脉后AA间期延长 40ms以上。③缺血再灌注组 40只兔子中 ,有 2 6只兔子于缺血期发生了窦性或房性心律失常 ,其中 15只于再灌注后 2 0min内恢复正常 ,但另有 3只发生了新的心律失常。④缺血再灌注组于缺血期有AA间期延长的 2 7只兔子 ,多在再灌注后 10min内恢复至结扎前水平 ,但缺血 60、12 0min再灌注组则随再灌注时间进一步延长 ,AA间期再次延长。结论 ①约 2 3的兔子窦房结动脉可能起源于右冠状动脉。②窦房结缺血引起的心电生理变化与病窦综合征的心电图表现相似。

Objective To study the effect of ischemia reperfusion(IR) on electrophysiological function of sinoatrial node(SAN) in rabbits. Methods Ninety healthy adult rabbits were divided randomly into control group, ischemia groups (I) 10(I10 min), 30(I30 min), 60(I60 min) and 120 min(I120 min) and IR groups (10, 30, 60 and 120 min ischemia followed by 4 h reperfusion respectively)(I10 minR4 h, I30 minR4 h, I60 minR4 h and I120 minR4 h). There were 10 rabbits in the control group and each subgroup. IR injury model of SAN was established by occluding and loosening the start section of right coronary artery(RCA). The changes of AA interval and arrhythmia were recorded by electrocardiography and cardiac chamber electrography synchronously. Results ① There was no significant difference in AA interval between different time points in the control group. ② Sinus arrest(SA), sinus bradycardia with arrhythmia(SB), or atrial tachyarrhythmia(AT) were found in 51 rabbits (63.75%) out of 80 rabbits in I and IR groups in ischemic period. The incidence rate of arrhythmia increased in a time dependent manner. The AA intervals also increased by at least 40 ms in 54 rabbits (67.5%). ③ Sinus or atrial arrhythmia during ischemic period was found in 26 out of the 40 rabbits in IR group, but 15 returned normal after reperfusion. ④ Increased AA intervals were found in 27 out of the 40 rabbits in IR group during ischemic period. Most of them recovered to pre occlusion level within 10 min after reperfusion, but the AA intervals prolonged again in I60 minR4 h and I120 minR4 h groups as the reperfusion elongated. Conclusion ① These findings suggest that about 2/3 of the rabbit sinus node arteries may stem from right coronary artery. ② Electrophysiological changes due to ischemia of SAN resemble the electrocardiogram of sick sinoatrial node syndrome. ③ Reperfusion arrhythmia can be induced by reperfusion after a long time of ischemia.