Ionic current basis of electrocardiographic waveforms - A model study
Ionic current basis of electrocardiographic waveforms - A model study
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DOI：
10.1161/01.res.0000016960.61087.86
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发表时间：
2002-05-03
影响因子：
20.1
通讯作者：
Rudy, Y
中科院分区：
文献类型：
--
作者：
Gima, K;Rudy, Y
体表心电图和从心脏表面记录的电图是诊断和治疗心脏电生理疾病和心律失常的基础。鉴于最近在理解心律失常的分子机制方面取得的进展，将这些心电图波形与细胞电生理过程联系起来是很重要的。本模型研究建立了以下原理：（1）由慢延迟整流（I-Ks）和瞬时外向（I-to）钾电流的不均匀性所产生的电压梯度分别刻划T波和J波，T波的极性和宽度受到通过缝隙连接的细胞间耦合程度的强烈影响。(2)[K+]（o）的变化通过其对快速延迟整流器I-Kr的影响来调节T波。(3)长QT综合征（分别为LQT 1、LQT 2和LQT 3）中I-Ks、I-Kr和I-Na（快钠电流）的改变反映在特征性QT间期和T波改变中，LQT 1 → QT而不增宽T波。(4)在心外膜I-Ω较大的背景下，I-Na的加速失活导致ST段抬高（Brugada表型），反映了严重程度。(5)ATP敏感性钾电流I-K（ATP）的激活足以导致急性缺血期间ST段抬高。这些原理为心电图波形的解释提供了一个机械的细胞基础。
Body surface electrocardiograms and electrograms recorded from the surfaces of the heart are the basis for diagnosis and treatment of cardiac electrophysiological disorders and arrhythmias. Given recent advances in understanding the molecular mechanisms of arrhythmia, it is important to relate these electrocardiographic waveforms to cellular electrophysiological processes. This modeling study establishes the following principles: (1) voltage gradients created by heterogeneities of the slow-delayed rectifier (I-Ks) and transient outward (I-to) potassium cur-rent inscribe the T wave and J wave, respectively T-wave polarity and width are strongly influenced by the degree of intercellular coupling through gap-junctions. (2) Changes in [K+](o) modulate the T wave through their effect on the rapid-delayed rectifier, I-Kr. (3) Alterations of I-Ks, I-Kr, and I-Na (fast sodium current) in long-QT syndrome (LQT1, LQT2, and LQT3, respectively) are reflected in characteristic QT-interval and T-wave changes LQT1 prolongs QT without Widening the T wave. (4) Accelerated inactivation of I-Na on the background of large epicardial I-omega results in ST elevation (Brugada phenotype) that reflects the degree of severity. (5) Activation of the ATP-sensitive potassium current, I-K(ATP), is Sufficient to cause ST elevation during acute ischemia. These principles provide a mechanistic cellular basis for interpretation of electrocardiographic waveforms.