LQT2模型中早期后除极的产生与中层心肌细胞的岛形分布有关  

The Generation o f Early Afterdepolarizations Relates With Distribution of M Cells Domain in the LQT2 Model

作　　者：金印彬[1] 杨琳[1] 张虹[2] 黄诒焯[2] 蒋大宗[2] 

机构地区：[1]西安交通大学第一医院心内科,陕西西安710061 [2]西安交通大学生命科学与技术学院

出　　处：《中国心脏起搏与心电生理杂志》2004年第5期384-387,共4页Chinese Journal of Cardiac Pacing and Electrophysiology

基　　金：国家自然科学基金资助课题 (批准号 :3 0 10 0 0 67)

摘　　要：用Luo Rudy心室肌细胞动作电位模型LRd0 0进行二维虚拟心室肌组织的仿真研究 ,探讨LQT2模型中早期后除极 (EAD)的产生与中层心肌 (M)细胞岛形分布的关系。通过设置快速激活延迟整流钾电流 (IKr)通道的电导为零 ,模拟动物实验中灌注d sotalol阻断IKr形成LQT2模型。在二维虚拟心室肌组织的心内膜侧加基础周长 (BCL)为5 0 0ms的刺激 10次 ,间歇 5 0 0 0ms后 ,再给一个单刺激。通过改变M细胞岛形分布的形状、大小和位置 ,观察M细胞分布与长QT综合征中发生EAD的关系。结果 :在本实验条件下 ,当M细胞岛型区域的形状、大小适当时 ,可产生EAD并维持EAD的不断发生 ,引起靠近心内膜区域与M细胞区域的交界处产生较高振幅的EAD ,形成由EAD触发激动引起并维持的折返激动。结论 :在LQT2模型中 ,M细胞跨壁岛型分布的形状、大小和位置是产生EAD以及室壁内折返环的形成与维持的重要因素。折返波起始于心内膜细胞区域与M细胞区域的交界处。The Luo-Rudy model (LRd00) of mammalian ventricular cell was used in simulating of two-dimensional (2-D) ventricular tissue. LQT2 model was achieved by setting t he maximum conductance of the I Kr channel to zero. This simulated the surrogate model of LQT2 in perfusion with d-sotalol (I Kr blockader) in animal experiments. The endocardium was paced 10 times at a constant basic cycle length(BCL) of 500 ms. Following a 5 00 0 ms pause, an additional single stimulus was applied. The relationship of distribution of M cells domain and the generation of early a fterdepolarizations(EADs) in the LQT2 model was studied by changing the shape, size and position of M cells domain. Result: Under this experiment condition, wh en the shape and size of M cells domain was suitable and closed to the endocardium, the EADs were generated and maintained i n M cell domain. Meanwhile, EADs with higher amplitude were seen near the boundary of endocardial domain and M cells domain. And then, the functional reentries were formed and maintained by EAD triggered activity. Conclusion: The shape, size, and posit ion of the distribution of M cells domain are important facts for EAD generation and reentrant formation and maintenance in tr ansmural ventricular wall in the LQT2 model. Reentrant activity is often generated at the boundary of two different tissue.

关 键 词：M细胞 心内膜 早期后除极 中层心肌 肌细胞 肌组织 EAD 大小 产生 结论 

分 类 号：R541[医药卫生—心血管疾病] R331[医药卫生—内科学]