The Ib phase of ventricular arrhythmias in ischemic in situ porcine heart is related to changes in cell-to-cell electrical coupling. Experimental Cardiology Group, University of North Carolina.
The Ib phase of ventricular arrhythmias in ischemic in situ porcine heart is related to changes in cell-to-cell electrical coupling. Experimental Cardiology Group, University of North Carolina.
复制标题
原位缺血猪心脏中室性心律失常的 Ib 期与细胞间电耦合的变化有关。
DOI：
10.1161/01.cir.92.10.3051
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发表时间：
1995
期刊：
影响因子：
37.8
通讯作者：
Cascio,WE
中科院分区：
文献类型：
--
作者：
Smith4th,WT;Fleet,WF;Johnson,TA;Engle,CL;Cascio,WE
背景本研究旨在验证缺血时细胞间电相互作用的丧失调节缺血引起的TQ段压低(即损伤电位)的幅度以及所谓的室性心律失常Ib期室颤(VF)的发生的假说。方法和结果结扎开胸中左前降支60min诱发局部缺血(n=10)。细胞间的电脱偶联被定义为全组织电阻率(RT)终末升高的开始。用单极电图法测定局部激活时间和TQ段变化(损伤电位)。用离子选择电极测定细胞外K+([K+]e)和pH(Phe)。10只猪中有6只在停止灌流后19~30min的局部无血流缺血时发生室颤。室性心动过速的发生与细胞间电脱耦联的开始呈正相关(R2=.885)。[K+]e和pH的变化叠加细胞间的电脱偶联，在停止灌流后19-30分钟内导致脉冲传播失败。缺血19min时，TQ段最大压低为−10 mV，之后缓慢恢复。TQ段恢复的开始与RT的第二次上升相关(R2=.886)。结论在局部缺血的猪原位心脏中，细胞间电相互作用的丧失与室颤的发生和损伤电流幅值的变化有关。由于[K+]E升高和Phe降低，在组织兴奋性改变的背景下，细胞电去偶联导致脉冲传播失败。这些数据表明，缺血时Ib心律失常和心电变化受细胞间电相互作用丧失的影响。
BackgroundThis study was designed to test the hypothesis that the loss of cell-to-cell electrical interaction during ischemia modulates the amplitude of ischemia-induced TQ-segment depression (ie, the injury potential) and the occurrence of ventricular fibrillation (VF) during the so-called Ib phase of ventricular arrhythmias.Methods and ResultsRegional ischemia was induced by 60 minutes of mid–left anterior descending coronary artery ligation in open-chest swine (n=10). Cell-to-cell electrical uncoupling was defined as the onset of the terminal rise in whole-tissue resistivity (Rt). Local activation times and TQ-segment changes (injury potential) were determined from unipolar electrograms. Extracellular K+([K+]e) and pH (pHe) were measured with plunge-wire ion-selective electrodes. VF occurred in 6 of 10 pigs during regional no-flow ischemia between 19 and 30 minutes after the arrest of perfusion. The occurrence of VF was positively correlated to the onset of cell-to-cell electrical uncoupling (R2=.885). Cell-to-cell electrical uncoupling superimposed on changes of [K+]eand pHecontributed to the failure of impulse propagation between 19 and 30 minutes after the arrest of perfusion. During ischemia, maximum TQ-segment depression was −10 mV at 19 minutes, after which TQ-segment depression slowly recovered. The onset of the TQ-segment recovery was correlated to the second rise in Rt(R2=.886).ConclusionsIn the regionally ischemic in situ porcine heart, loss of cell-to-cell electrical interaction is related to the occurrence of VF and changes in the amplitude of the injury current. Cellular electrical uncoupling contributes to failure of impulse propagation in the setting of altered tissue excitability as a result of elevated [K+]eand low pHe. These data indicate that Ib arrhythmias and ECG changes during ischemia are influenced by the loss of cell-to-cell electrical interaction.