Intracellular Ca dynamics in ventricular fibrillation
Intracellular Ca dynamics in ventricular fibrillation
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DOI：
10.1152/ajpheart.00123.2003
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发表时间：
2004-05-01
影响因子：
4.8
通讯作者：
Weiss, JN
中科院分区：
文献类型：
--
作者：
Omichi, C;Lamp, ST;Weiss, JN
在心脏中，膜电压 (V-m) 和细胞内 Ca (Ca-i) 是双向耦合的，因此离子膜电流调节 Ca-i 循环，Ca-i 影响离子电流调节动作电位持续时间 (APD)。尽管 Ca-i 在正常心率下可靠且一致地跟踪 V-m，但在非常快的心率下，肌浆网 Ca-i 循环可能会表现出内在的动力学。非电压门控 Ca-i 释放可能会导致 APD 和不应期的局部变化，从而影响心室颤动 (VF) 期间的波断。在本研究中，我们通过检查 VF 期间 Ca-i 与 V-m 的关联程度来检验这一假设。使用荧光染料 rhod 2 AM 在离体动脉灌注的猪右心室中对 Ca-i 瞬变进行光学映射，同时使用微电极（5 个制剂）局部记录或使用电压敏感染料 RH-237（5 个制剂）全局记录细胞内膜电位。互信息 (MI) 是对一个变量 (V-m) 的知识预测第二个变量 (Ca-i) 值的程度的定量统计度量。 MI 在起搏和室性心动过速期间较高（VT；分别为 1.13+/-0.21 和 1.69+/-0.18），但在 VF 期间急剧下降（0.28+/-0.06，P
In the heart, membrane voltage (V-m) and intracellular Ca (Ca-i) are bidirectionally coupled, so that ionic membrane currents regulate Ca-i cycling and Ca-i affects ionic currents regulating action potential duration (APD). Although Ca-i reliably and consistently tracks V-m at normal heart rates, it is possible that at very rapid rates, sarcoplasmic reticulum Ca-i cycling may exhibit intrinsic dynamics. Non-voltage-gated Ca-i release might cause local alternations in APD and refractoriness that influence wavebreak during ventricular fibrillation (VF). In this study, we tested this hypothesis by examining the extent to which Ca-i is associated with V-m during VF. Ca-i transients were mapped optically in isolated arterially perfused swine right ventricles using the fluorescent dye rhod 2 AM while intracellular membrane potential was simultaneously recorded either locally with a microelectrode (5 preparations) or globally with the voltage-sensitive dye RH-237 (5 preparations). Mutual information (MI) is a quantitative statistical measure of the extent to which knowledge of one variable (V-m) predicts the value of a second variable (Ca-i). MI was high during pacing and ventricular tachycardia (VT; 1.13+/-0.21 and 1.69+/-0.18, respectively) but fell dramatically during VF (0.28+/-0.06, P