Multiarm spirals in a two-dimensional cardiac substrate
Multiarm spirals in a two-dimensional cardiac substrate
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DOI：
10.1073/pnas.0400984101
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发表时间：
2004-10-26
影响因子：
11.1
通讯作者：
Tung, L
中科院分区：
文献类型：
--
作者：
Bursac, N;Aguel, F;Tung, L
包括心脏组织在内的多种化学和生物非线性可兴奋介质，能够以旋转单臂螺旋的形式支持稳定的、自组织的活动波。特别是，心脏组织可以支持静止和蜿蜒的电兴奋螺旋，这已被证明是不同形式的心律失常的基础。与单臂螺旋相反，稳定的多臂螺旋（围绕一个共同的组织中心以相同方向旋转的多个螺旋波）尚未在活的可兴奋组织中得到证实和研究。在这里，我们表明，在单臂螺旋活动期间施加短而快速的电点刺激，可以在单层培养的新生大鼠心脏细胞中诱导持续的多臂螺旋电活动。只有在脉冲波长和传播速度对激发速率具有相对广泛和陡峭的依赖性的单层中才能实现稳定的形成。由此产生的多臂螺旋比单臂螺旋释放的电活动波的速度更快，并表现出两种不同的行为，即“臂切换”和“尖端切换”。由于螺旋臂数量的增加而导致的心率加速现象可能是临床医生或抗心动过速装置所定速的功能性再入性心动过速加速的基础。
A variety of chemical and biological nonlinear excitable media, including heart tissue, can support stable, self-organized waves of activity in a form of rotating single-arm spirals. In particular, heart tissue can support stationary and meandering spirals of electrical excitation, which have been shown to underlie different forms of cardiac arrhythmias. In contrast to single-arm spirals, stable multiarm spirals (multiple spiral waves that rotate in the same direction around a common organizing center) have not been demonstrated and studied yet in living excitable tissues. Here, we show that persistent multiarm spirals of electrical activity can be induced in monolayer cultures of neonatal rat heart cells by a short, rapid train of electrical point stimuli applied during single-arm-spiral activity. Stable formation is accomplished only in monolayers that show a relatively broad and steep dependence of impulse wavelength and propagation velocity on rate of excitation. The resulting multiarm spirals emit waves of electrical activity at rates faster than for single-arm spirals and exhibit two distinct behaviors, namely "arm-switching" and "tip-switching." The phenomenon of rate acceleration due to an increase in the number of spiral arms possibly may underlie the acceleration of functional reentrant tachycardias paced by a clinician or an antitachycardia device.