Cardiac contraction induces discordant alternans and localized block.
Cardiac contraction induces discordant alternans and localized block.
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心脏收缩引起不协调的交替和局部阻滞
DOI：
10.1103/physreve.91.022703
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
B. Echebarria
中科院分区：
文献类型：
--
作者：
M. Radszuweit;E. Alvarez-Lacalle;M. Bär;B. Echebarria
在本文中，我们使用心脏兴奋-收缩耦合的简化模型来研究组织变形对交替动力学的影响，即心脏动作电位持续时间的交替，这种交替发生在快速起搏速率下，并且已知是致心律失常的。我们表明，小的拉伸激活电流可以产生很大的影响，并导致从同相交替到异相交替（即从一致交替到不一致交替）和传导阻滞的转变。我们通过数值和分析证明，这种效应是由于机电耦合导致传导速度恢复曲线斜率发生一般变化的结果。因此，兴奋-收缩耦合可能在折返和颤动的过渡中发挥相关作用。
In this paper we use a simplified model of cardiac excitation-contraction coupling to study the effect of tissue deformation on the dynamics of alternans, i.e., alternations in the duration of the cardiac action potential, that occur at fast pacing rates and are known to be proarrhythmic. We show that small stretch-activated currents can produce large effects and cause a transition from in-phase to off-phase alternations (i.e., from concordant to discordant alternans) and to conduction blocks. We demonstrate numerically and analytically that this effect is the result of a generic change in the slope of the conduction velocity restitution curve due to electromechanical coupling. Thus, excitation-contraction coupling can potentially play a relevant role in the transition to reentry and fibrillation.