Garzón Alejandro, Grigoriev Roman O
Department of Mathematics, Universidad Sergio Arboleda, Bogotá 110221, Colombia.
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
Chaos. 2017 Sep;27(9):093917. doi: 10.1063/1.4999601.
The mechanisms underlying cardiac fibrillation have been investigated for over a century, but we are still finding surprising results that change our view of this phenomenon. The present study focuses on the transition from normal rhythm to spiral wave chaos associated with a gradual increase in the pacing rate. While some of our findings are consistent with existing experimental, numerical, and theoretical studies of this problem, one result appears to contradict the accepted picture. Specifically we show that, in a two-dimensional model of paced homogeneous atrial tissue, transition from discordant alternans to conduction block, wave breakup, reentry, and spiral wave chaos is associated with the transient growth of finite amplitude disturbances rather than a conventional instability. It is mathematically very similar to subcritical, or bypass, transition from laminar fluid flow to turbulence, which allows many of the tools developed in the context of fluid turbulence to be used for improving our understanding of cardiac arrhythmias.
心脏颤动背后的机制已被研究了一个多世纪，但我们仍不断发现令人惊讶的结果，这些结果改变了我们对这一现象的看法。本研究聚焦于随着起搏频率逐渐增加，从正常节律向螺旋波混沌的转变。虽然我们的一些发现与关于这个问题的现有实验、数值和理论研究一致，但有一个结果似乎与公认的情况相矛盾。具体而言，我们表明，在一个二维的起搏均匀心房组织模型中，从不协调交替变化到传导阻滞、波破裂、折返和螺旋波混沌的转变与有限振幅扰动的瞬态增长有关，而非传统的不稳定性。这在数学上与从层流到湍流的亚临界或旁路转变非常相似，这使得在流体湍流背景下开发的许多工具可用于增进我们对心律失常的理解。
