The deformation of the heart tissue due to the contraction can modulate the excitation, a phenomenon referred to as mechano-electrical feedback (MEF), via stretch-activated channels (SACs). The effects of MEF on the electrophysiology at high pacing rates are shown to be proarrhythmic in general. However, more study needs to be done to elucidate the underlying mechanism. In this work, we investigate the effects of MEF on cardiac alternans, which is an alternation in the width of the action potential and that typically occurs when the heart is paced at high rates, using a biophysically detailed electromechanical model of cardiac tissue. We observe that the transition from spatially concordant alternans (SCA) to spatially discordant alternans (SDA), which is more arrhythmogenic than SCA, may occur in the presence of MEF and when its strength is sufficiently large. We show that this transition is due to the increase of the dispersion of conduction velocity (CV). In addition, our results also show that the MEF effects, depending on the SACs' conductances and reversal potentials, can result in blocking action potential propagation.

中文翻译：

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机械牵张在心脏交替期间心律失常发生中作用的模拟研究

由于收缩引起的心脏组织变形可以通过拉伸激活通道 (SAC) 调节激发，这种现象称为机械电反馈 (MEF)。MEF 在高起搏率下对电生理学的影响通常是促心律失常的。然而，需要做更多的研究来阐明潜在的机制。在这项工作中，我们使用心脏组织的生物物理详细机电模型研究了 MEF 对心脏交替的影响，这是动作电位宽度的变化，通常发生在心脏以高速率起搏时。我们观察到从空间一致交替信号 (SCA) 到空间不一致交替信号 (SDA) 的转变，这比 SCA 更容易引起心律失常，在 MEF 存在且其强度足够大的情况下可能会发生。我们表明，这种转变是由于传导速度（CV）分散的增加。此外，我们的结果还表明，MEF 效应取决于 SAC 的电导和反转电位，可导致动作电位传播受阻。