Dynamic restitution of action potential duration during electrical alternans and ventricular fibrillation
Dynamic restitution of action potential duration during electrical alternans and ventricular fibrillation
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DOI：
10.1152/ajpheart.1998.275.5.h1635
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发表时间：
1998-11-01
影响因子：
4.8
通讯作者：
Gilmour, RF
中科院分区：
文献类型：
--
作者：
Koller, ML;Riccio, ML;Gilmour, RF
研究了犬浦肯野纤维（P; n = 9）和内膜肌（M; n = 9）起搏、离体灌流犬左心室心室颤动（VF; n = 4）和以VF周期起搏的内膜肌（模拟VF; n = 4）动作电位时程（APD）的恢复动力学。使用两种方案评估呼吸：在周期长度= 300 ms的一系列刺激后输送单次额外刺激（标准方案），以及诱导APD交替的短周期长度（100-300 ms）的固定起搏（动态方案）。动态协议产生了一个单调增加的恢复功能，最大斜率为1.13 +/- 0.13 M和1.14 +/- 0.17 P。迭代此功能再现APD动态实验发现，包括持续APD交替。相比之下，标准方案产生的恢复关系的最大斜率为0.57 +/- 0.18（M）和0.84 +/- 0.20（P），并且该函数的迭代没有再现APD动力学。在VF期间，短舒张间期的恢复动力学与动态方案确定的恢复动力学相似（最大斜率：VF为1.72 +/- 0.47，模拟VE为1.44 +/- 0.49）。因此，固定起搏和VF期间短耦合间期的APD动力学由动态恢复关系（而非标准恢复关系）解释。这些结果进一步证明了VF期间电恢复动力学、APD交替的发生和复杂的APD动力学之间的密切关系。
The restitution kinetics of action potential duration (APD) were investigated in paced canine Purkinje fibers (P; n = 9) and endocardial muscle (M; n = 9), in isolated, perfused canine left ventricles during ventricular fibrillation (VF; n = 4), and in endocardial muscle paced at VF cycle lengths (simulated VF; n = 4). Restitution was assessed with the use of two protocols: delivery of a single extrastimulus after a train of stimuli at cycle length = 300 ms (standard protocol), and fixed pacing at short cycle lengths (100-300 ms) that induced APD alternans (dynamic protocol). The dynamic protocol yielded a monotone increasing restitution function with a maximal slope of 1.13 +/- 0.13 in M and 1.14 +/- 0.17 in P. Iteration of this function reproduced the APD dynamics found experimentally, including persistent APD alternans. In contrast, the standard protocol yielded a restitution relation with a maximal slope of 0.57 +/- 0.18 in M and 0.84 +/- 0.20 in P, and iteration of this function did not reproduce the APD dynamics. During VF, the restitution kinetics at short diastolic interval were similar to those determined with the dynamic protocol (maximal slope: 1.72 +/- 0.47 in VF and 1.44 +/- 0.49 in simulated VE). Thus APD dynamics at short coupling intervals during fixed pacing and during VF were accounted for by the dynamic, but not the standard, restitution relation. These results provide further evidence for a strong relationship among the kinetics of electrical restitution, the occurrence of APD alternans, and complex APD dynamics during VF.