Effect of ischemia reperfusion on electrophysiological function of sinoatrial node in rabbits / 第三军医大学学报

ABSTRACT

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.