CYCLE LENGTH EFFECT ON RESTITUTION OF ACTION-POTENTIAL DURATION IN DOG CARDIAC FIBERS
CYCLE LENGTH EFFECT ON RESTITUTION OF ACTION-POTENTIAL DURATION IN DOG CARDIAC FIBERS
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DOI：
10.1152/ajpheart.1983.244.6.h782
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发表时间：
1983-01-01
影响因子：
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通讯作者：
SURAWICZ, B
中科院分区：
文献类型：
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作者：
ELHARRAR, V;SURAWICZ, B
在两种不同的基本周期长度（BCL，1500和500 ms）下，测定浦肯野纤维（n = 8）和心室肌纤维（n = 6）的动作电位时程（APD）的电恢复。针对最长APD（恢复平台）进行归一化的恢复曲线拟合了快速（T1）和慢速（T2）指数分量的总和。心室肌的T1短于浦肯野纤维（89 . ±. 5和143 .+-. 9;平均值±。SE，P < 0.05），而T2无差异（1448 . ±. 231和1439 .+-. 211）。BCL改变了恢复平台期的APD值，但没有改变2个指数分量。在这两种纤维类型中，APD和BCL之间的关系在稳态拟合的双曲线，预测在长BCL的最大APD的实现。恢复曲线在2个点处与稳态曲线相交，勾勒出APD间期的3个不同区域：早早、晚早和过熟。在恢复期，晚早熟区的APD长于稳态，而过成熟区和早早熟区的APD短于稳态。APD本身，独立的BCL，不影响动力学的恢复浦肯野纤维。
Electrical restitution of action potential duration (APD) was determined in Purkinje (n = 8) and ventricular muscle (n = 6) fibers at 2 different basic cycle lengths (BCL, 1500 and 500 ms). Restitution curves, normalized for the longest APD (the plateau of restitution), fitted the sum of a fast (T1) and a slow (T2) exponential component. The T1 was shorter in ventricular muscle than Purkinje fibers (89 .+-. 5 and 143 .+-. 9; mean .+-. SE, P < 0.05), whereas the T2 did not differ (1448 .+-. 231 and 1439 .+-. 211). The BCL altered the APD value during the plateau of restitution but did not change the 2 exponential components. In both fiber types, the relation between APD and BCL during steady state fitted a hyperbolic curve that predicts the achievement of the maximum APD at long BCL. The restitution curves crossed the steady-state curve at 2 points outlining 3 different zones of APD intervals: early premature, late premature, and postmature. The APD during restitution was longer than the steady state in the late premature zone and shorter than the steady-state APD in the post-mature and early premature zones. The APD per se, independent of BCL, did not influence the kinetics of restitution in Purkinje fibers.