Wavelet formation in excitable cardiac tissue: the role of wavefront-obstacle interactions in initiating high-frequency fibrillatory-like arrhythmias.
Wavelet formation in excitable cardiac tissue: the role of wavefront-obstacle interactions in initiating high-frequency fibrillatory-like arrhythmias.
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DOI：
10.1016/s0006-3495(96)79624-8
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发表时间：
1996-02
影响因子：
3.4
通讯作者：
J. Starobin;Y. Zilberter;E. M. Rusnak;C. Starmer
中科院分区：
文献类型：
--
作者：
J. Starobin;Y. Zilberter;E. M. Rusnak;C. Starmer
导致纤颤的高频心律失常通常与心脏组织中存在不均匀性（障碍物）和心脏细胞兴奋性降低有关。抗心律失常药物在心肌梗死存活患者中的研究显示，与未经治疗的患者相比，心脏性猝死的发生率增加。这些药物阻断心脏钠通道，从而降低兴奋性，这可能会改变波前障碍的相互作用。在患病的心房组织中，兴奋性通过继发于去极化静息电位的钠通道可用性降低和继发于细胞间纤维化的细胞解耦而降低。连续激励之间的不完全恢复也会降低兴奋性。在所有这些情况下，波前障碍物的相互作用，在一个不良的兴奋介质可能反映了一个embrymogenic过程，允许形成折返小波，导致扑动，纤颤，心脏猝死。为了探索激发性和子波生成之间的关系，我们探讨了在均匀激发介质中平面波与障碍物碰撞后新子波形成的条件。制定我们的方法在波前中的电荷和相邻介质的激发电荷要求之间的平衡，我们发现分析的临界介质参数，定义波前障碍分离的条件。在这些条件下，当父波阵面与原始障碍物碰撞时，所产生的碎片从障碍物边界分离，随后卷曲，并产生新的“子”小波。我们确定了障碍物的空间排列，使得波前-障碍物碰撞导致产生新的小波，从而产生类似于纤维性心律失常的高频小波序列。
High-frequency arrhythmias leading to fibrillation are often associated with the presence of inhomogeneities (obstacles) in cardiac tissue and reduced excitability of cardiac cells. Studies of antiarrhythmic drugs in patients surviving myocardial infarction revealed an increased rate of sudden cardiac death compared with untreated patients. These drugs block the cardiac sodium channel, thereby reducing excitability, which may alter wavefront-obstacle interactions. In diseased atrial tissue, excitability is reduced by diminished sodium channel availability secondary to depolarized rest potentials and cellular decoupling secondary to intercellular fibrosis. Excitability can also be reduced by incomplete recovery between successive excitations. In all of these cases, wavefront-obstacle interactions in a poorly excitable medium may reflect an arrhythmogenic process that permits formation of reentrant wavelets leading to flutter, fibrillation, and sudden cardiac death. To probe the relationship between excitability and arrhythmogenesis, we explored conditions for new wavelet formation after collision of a plane wave with an obstacle in an otherwise homogeneous excitable medium. Formulating our approach in terms of the balance between charge available in the wavefront and the excitation charge requirements of adjacent medium, we found analytically the critical medium parameters that defined conditions for wavefront-obstacle separation. Under these conditions, when a parent wavefront collided with a primitive obstacle, the resultant fragments separated from the obstacle boundaries, subsequently curled, and spawned new "daughter" wavelets. We identified spatial arrangements of obstacles such that wavefront-obstacle collisions leading to spawning of new wavelets could produce high-frequency wavelet trains similar to fibrillation-like arrhythmias.