Controllability of voltage- and calcium-driven cardiac alternans in a map model.
Controllability of voltage- and calcium-driven cardiac alternans in a map model.
复制标题
地图模型中电压和钙驱动的心脏交替的可控性。
作者：
Laura M. Muñoz;Mark O. Ampofo;E. Cherry
某些心律失常发生之前会出现电交替，这是一种以细胞动作电位持续时间逐搏交替为特征的状态。心脏交替可能由不同的机制引起，包括电压或细胞内钙循环的不稳定。尽管已经提出了许多技术来抑制交替糖，但这些方法主要是使用不支持钙驱动交替糖的模型进行测试的。因此，了解当钙循环不稳定驱动交替糖时控制方法如何发挥作用非常重要。在这项研究中，我们将可控性分析应用于心脏细胞中交替动力学的离散图。我们比较了两种不同的可控性措施，以确定不同的控制策略可以在多大程度上抑制交替，并使用三个反馈控制器测试这些预测。我们发现，与可控性矩阵的最小奇异值不同，模态可控性测度始终表明需要最少控制努力并产生最小闭环特征值的控制策略。此外，动作电位持续时间被认为是最有效的变量，通过它可以应用控制，无论交替机制如何，尽管肌浆网钙负荷对于钙驱动的交替病例也很有用。
Certain cardiac arrhythmias are preceded by electrical alternans, a state characterized by beat-to-beat alternation in cellular action potential duration. Cardiac alternans may arise from different mechanisms including instabilities in voltage or intracellular calcium cycling. Although a number of techniques have been proposed to suppress alternans, these methods have mainly been tested using models that do not support calcium-driven alternans. Therefore, it is important to understand how control methods may perform when alternans is driven by instabilities in calcium cycling. In this study, we applied controllability analysis to a discrete map of alternans dynamics in a cardiac cell. We compared two different controllability measures to determine to what extent different control strategies could suppress alternans and tested these predictions using three feedback controllers. We found a modal controllability measure, unlike the minimum singular value of the controllability matrix, consistently indicated the control strategies requiring the least control effort and yielding the smallest closed-loop eigenvalue. In addition, action potential duration was identified as the most effective variable through which control can be applied, regardless of alternans mechanism, although sarcoplasmic reticulum calcium load was also useful for the calcium-driven alternans cases.