家兔快速心房起搏所致电重构和解剖重构及其时间进程的研究

The Characteristics and Time Course of Electrical and Anatomical Remodeling in Rapid Atrial Pacing in Rabbits.

对家兔短期快速心房起搏所致的心房肌电重构和解剖重构特征和时间进程加以研究。 2 0只家兔经颈内静脉切开置入电极导管定位于右房 ,以最快的心房 1∶1起搏频率行快速心房起搏 8h ,分别于起搏前、起搏后 0 .5 ,1,2 ,4 ,6 ,8h及停止起搏后 10 ,2 0 ,30min测定心房有效不应期 (AERP) ,并分别取未起搏 ,起搏 4 ,8h家兔的右心耳组织 ,观察其超微结构。结果 :快速心房起搏后AERP缩短 ,刺激频率 2 0 0 ,2 5 0ms的AERP的最小值出现在快速心房起搏后 1h ,起搏后 0 .5h内AERP变化速率最大 ,在其后的整个短期起搏过程中在较低水平波动 ,停止起搏 10min即可恢复 95 %以上。快速心房起搏 4 ,8h后心房肌细胞超微结构可见线粒体肿胀 ,糖原聚集 ,肌浆网和胞核无明显变化。结论 :短期快速心房起搏可导致心房肌电重构 ,以AERP缩短为特征的电重构在起搏后 0 .5h即可发生 ,其时间进程表现为发生快 ,短期起搏停止后逆转快的特点 。

Department of Cardiology,Shandong Provincial Qianfushan Hospital,Jinan 250014,ChinaTo study the characteristics and the time course of electrical and anatomical remodeling in rabbits of rapid atrial pacing,20 rabbits paced with maximal atrial capture rate for 8 hours in the right atrial.Atrial effective refroctoriness period (AERP) were observed from 0 to 8 hours after the onset of the pacing and also from 10 to 30 minutes after offset of the pacing.The atrial myocardium were collected at 0,4,8hours after pacing and were examined by eletron microscopy.Result:There was a prompt decrease in AERP as the result of rapid atrial pacing.The minimum value of AERP 200 ,AERP 150 occurred after 1 hour of rapid atrial pacing and an initial drop were taken in first 0.5 hour.After 8 hours pacing,the AERP recovered quickly with a return to within 95% of baseline after 10 minutes.Electron microscopic studies of right atricular appendage tissue demonstrated that mitochondrial swelling and accumulation of glycogen were observed in rabbits paced for 4,8 hours.The sarcoplasmic reticulum and nuclei were normal.Conclusion:Short term atrial rapid pacing reduces atrial electrical remodeling,which develops quickly after pacing and recovers quickly after the offset of rapid pacing.The ultrastructural changes may be observed after short term atrial pacing.