Memory and complex dynamics in cardiac Purkinje fibers.
Memory and complex dynamics in cardiac Purkinje fibers.
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DOI：
10.1152/ajpheart.1997.272.4.h1826
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发表时间：
1997-04
期刊：
影响因子：
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通讯作者：
R. Gilmour;N. Otani;Mari A. Watanabe
中科院分区：
文献类型：
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作者：
R. Gilmour;N. Otani;Mari A. Watanabe
在犬心脏浦肯野纤维中研究了动作电位时程（记忆）累积变化对复杂细胞电生理行为的贡献。恒定起搏期间诱导的复杂行为是由完全复极时间（TFR）（TFR =反应持续时间+潜伏期）和舒张间期（DI）之间的相互作用引起的。在复杂的行为过程中，TFR和先前的DI之间的关系不同于使用标准恢复协议获得的关系。特别是，高阶周期性和混沌产生的纤维中的恢复曲线缺乏这样的行为的先决条件。为了研究在快速起搏过程中恢复曲线是否会发生偏移，确定了测试反应的TFR（n + 1）和前一反应（n））之间的关系。对于任何固定的DI（n），TFR（n）从240 ms降低至130 ms伴随着TFR（n + 1）的相应降低，而当TFR（n）进一步降低至120 ms时，TFR（n + 1）增加。由于TFR（n + 1）依赖于TFR（n）（记忆）和先前的DI（n）（恢复），在恒定起搏周期长度下TFR（n + 1）和DI（n）之间低维关系的斜率取决于恢复和记忆函数的斜率。这些结果表明，记忆的快速积累和消散可能对心脏组织中复杂的电行为有重要贡献。
The contribution of cumulative changes in action potential duration (memory) to complex cellular electrophysiological behavior was investigated in canine cardiac Purkinje fibers. Complex behavior induced during constant pacing was caused by reciprocal interactions between the time to full repolarization (TFR), where TFR = response duration + latency, and the diastolic interval (DI). The relationship between TFR and the preceding DI during complex behavior differed from that obtained using a standard restitution protocol. In particular, higher-order periodicities and chaos were produced in fibers in which the restitution curve lacked the prerequisites for such behavior. To investigate whether shifts in the restitution curve might be expected during rapid pacing, the relationship between TFR of a test response (TFR(n + 1)) and the immediately preceding response (TFR(n)) was determined. For any fixed DI(n), reduction of TFR(n) from 240 to 130 ms was accompanied by a corresponding reduction of TFR(n + 1), whereas as TFR(n) was reduced further to 120 ms, TFR(n + 1) increased. Because of the dependence of TFR(n + 1) on TFR(n) (memory) and on the preceding DI(n) (restitution), the slope of the low-dimensional relationship between TFR(n + 1) and DI(n) at a constant pacing cycle length depended on the slopes of the restitution and memory functions. These results suggest that rapid accumulation and dissipation of memory may contribute importantly to complex electrical behavior in cardiac tissue.