Suppression of alternans and conduction blocks despite steep APD restitution: electrotonic, memory, and conduction velocity restitution effects
Suppression of alternans and conduction blocks despite steep APD restitution: electrotonic, memory, and conduction velocity restitution effects
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DOI：
10.1152/ajpheart.00747.2003
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发表时间：
2004-06-01
影响因子：
4.8
通讯作者：
Fenton, FH
中科院分区：
文献类型：
--
作者：
Cherry, EM;Fenton, FH
当考虑电紧张效应和记忆效应时，我们研究了动作电位（AP）持续时间（APD）恢复曲线斜率在预测电交替发生方面的效用。我们开发并使用了两种没有记忆的离子电池模型，它们具有相同的斜率为>1的恢复曲线，但AP形状不同，因此具有不同的电紧张效应。我们还研究了第三种细胞模型，该模型包含了之前周期长度的短期记忆，因此它具有一系列S1-S2恢复曲线以及斜率为bbb1的动态恢复曲线。我们的研究结果表明，即使在APD恢复曲线陡峭的情况下，电紧张效应和记忆效应都可以抑制交替。在缺乏记忆的情况下，与AP形状相关的电紧张电流，以及传导速度恢复，可以影响组织中交替的发展，在某些情况下，可以完全阻止其诱导，即使在分离的细胞中也表现出交替。当包括短期记忆时，尽管APD恢复曲线陡峭，但交替可能不会发生在孤立的细胞中，并且可能会或可能不会发生在组织中，这取决于传导速度的恢复。我们首次展示了电紧张和记忆效应可以防止传导阻滞和稳定二维和三维的可重入波。因此，我们发现单独的APD恢复曲线的斜率并不总是很好地预测交替的开始，结合电紧张和记忆效应可能提供一个更有用的交替标准。包含电影和JAVA小程序的数据补充可以在http://ajpheart.physiology.org.cgi/content/full/00747.2003/DC1上在线获得。
We examine the utility of the action potential (AP) duration (APD) restitution curve slope in predicting the onset of electrical alternans when electrotonic and memory effects are considered. We develop and use two ionic cell models without memory that have the same restitution curve with slope >1 but different AP shapes and, therefore, different electrotonic effects. We also study a third cell model that incorporates short-term memory of previous cycle lengths, so that it has a family of S1-S2 restitution curves as well as a dynamic restitution curve with slope >1. Our results indicate that both electrotonic and memory effects can suppress alternans, even when the APD restitution curve is steep. In the absence of memory, electrotonic currents related to the shape of the AP, as well as conduction velocity restitution, can affect how alternans develops in tissue and, in some cases, can prevent its induction entirely, even when isolated cells exhibit alternans. When short-term memory is included, alternans may not occur in isolated cells, despite a steep APD restitution curve, and may or may not occur in tissue, depending on conduction velocity restitution. We show for the first time that electrotonic and memory effects can prevent conduction blocks and stabilize reentrant waves in two and three dimensions. Thus we find that the slope of the APD restitution curve alone does not always well predict the onset of alternans and that incorporating electrotonic and memory effects may provide a more useful alternans criterion. A Data Supplement containing movies and JAVA applets is available online at http://ajpheart.physiology.org.cgi/content/full/00747.2003/DC1.