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牵张所致心室不应性变化的频率依赖现象及其机制

王兴祥, 程龙献, 陈君柱, 周利龙, 朱建华, 郭晓纲, 尚云鹏

浙江大学医学院第一附属医院心内科暨心血管病研究所，杭州310003

摘要

旨在探讨牵张所致麻醉兔心室不应性变化的频率依赖现象及其机制。采用部分夹闭兔主动脉根AI以增加左室后负荷的在体心脏模型，观察不同起搏周长时左室后负荷增加后心室有效不应期(effective refractory period, ERP)的变化及链霉素对此的影响。结果显示，当起搏周长为1 000和500 ms时，左室收缩期内压增加后的心靡E RP较主动脉夹闭前略有缩短(1 000 ms , 3士2 ms , 1. 5 % ; 500 ms , 7士3 ms , 4. 0 % . P > 0. 05)，而起搏周长300和20(m、时则明显缩短(300 ms , 21士5 ms ,17.0%;200 ms ,19士ms,18.8%. P<0.01);(2)链霉素可有效消除基本驱动括长30。和200 ms时左心室后负荷增加对E RP的影响(P>0.05，组内比较)。结果提示，牵张所致心室E RP变化具有快频率依赖性，且链霉素通过抑制牵张激活性离子通道的活化而消除这种电生理效应。

关键词： 不应期; 链霉素; 机一电反馈; 兔

Dependence of ventricular wallstress induced refractoriness changes on pacing cycle lengths and its mechanism

WANG Ring- Mang, CHENG Long- Ma, CHEN Juir Zhu, ZHOU Li-Long, ZGUO Xiao- Gang, SHANG YunPen

Cardiovascular Disease Department First Hospital Affiliated to Wical College of Zhejiang Universitylar Disease Department , Union Hospital Affiliated to Tongji Medical College Huazhong University Science and Technology，Wuhan 430022

Abstract

The aim of this article was to investigate the dependence of ventricular wallstress-induced refractoriness changes on pacing cycle lengths and its mechanism in anaesthetized rabbits .The rabbit heart preparation
was use d .The left ventricular afterload was increased by partially clipping the root of the ascending aorta .The changes in effective refractory periods(ERP) induced妙the left ventricular afterload rising were examined at dif-
ferent pacing cycle lengths(1 000，500，300 and 200 ms).In addition，the effect of streptomycin on these changes was also observed .The results are as follows:(1)The rising of left ventricular afterload led to marked
changes in ERP at rapidly pacing cycle lengths(300 ms，21士5 ms，17.0;200 ms，19士3 ms，18.8.P <0.01)than at slow ones(1 000 ms，3士2 ms，1 .5;500 ms，7士3 ms，4.0.P>0.05);(2) Streptomycin inhibited the changes caused by the left ventricular afterload rising at pacing cycle lengths 300 ms and 200
ms(P>0.05).It is suggested that ventricular wallstress-induced refractoriness changes are pacing cycle lengthdependent，and the effect of streptomycin appears to be consistent with the inhibition of stretch-activated ion
channels.

Key words: repfractoiy period;streptomycin;mechano-electric feedback;rabbit

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引用本文：

王兴祥, 程龙献, 陈君柱, 周利龙, 朱建华, 郭晓纲, 尚云鹏. 牵张所致心室不应性变化的频率依赖现象及其机制[J]. 生理学报 2003; 55 (3): .

WANG Ring- Mang, CHENG Long- Ma, CHEN Juir Zhu, ZHOU Li-Long, ZGUO Xiao- Gang, SHANG YunPen. Dependence of ventricular wallstress induced refractoriness changes on pacing cycle lengths and its mechanism. Acta Physiol Sin 2003; 55 (3): (in Chinese with English abstract).