Identification of conduction block in cardiac muscle: in vitro observations in canine epicardium.
Identification of conduction block in cardiac muscle: in vitro observations in canine epicardium.
复制标题
心肌传导阻滞的识别：犬心外膜的体外观察。
DOI：
10.1093/cvr/28.2.259
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发表时间：
1994
影响因子：
10.8
通讯作者：
Spear,J
中科院分区：
文献类型：
--
作者：
Kadish,A;Spear,J
目的：目的是检验先前提出的几个标准和“向量图”区分犬心肌慢传导和传导阻滞的能力。方法：使用两种不同的犬心外膜体外制剂。在 10 个组织中，通过切口模拟解剖屏障（五个纵向切口和五个横向切口）。还研究了闭塞再灌注梗塞两周后取出的十一种组织。等时激活图是根据细胞外和细胞内记录构建的，并且通过将两个正交记录的双极电描记图相加而形成的矢量环用于指示心脏激活的方向。 结果：在切割模型中，从解剖屏障上记录的电描记图通常是正常的或显示双电势，但有时可能会被分割。从细胞外记录获得的等时激活图能够识别横向于纤维方向的五个解剖障碍中的五个，但仅识别纵向于纤维方向的五个障碍中的一个。由矢量环指示的心脏激活方向在所有 10 种制剂中识别出传导阻滞。在从患有实验性心肌梗塞的犬心室中取出的 11 个组织中，使用微电极记录来表征慢传导或传导阻滞的区域。从细胞外记录获得的等时激活模式通常显示脉冲通过传导区和传导阻滞区周围，但在 11 例中有 2 例中与微电极刺穿的结果不一致。电图形态也并不总是能够区分慢传导和传导阻滞。通过矢量测绘确定的心脏激动方向准确地表征了所有组织区域的慢传导或传导阻滞。结论：从实验性心肌梗死中取出的心外膜组织中经常存在有限的传导阻滞或慢传导区域。细胞外电图的形态和从细胞外记录执行的等时激活图通常但并不总是能够区分慢传导和传导阻滞。在这些情况下，矢量映射可用于区分慢速传导和传导阻滞，并可能有助于评估心肌传导模式。心血管研究1994；28：259-269
Objective:The aim was to examine the ability of several previously proposed criteria and of “vector mapping” to distinguish slow conduction from conduction block in canine myocardium.Methods:Two different in vitro preparations of canine epicardium were used. In 10 tissues, an anatomical barrier was simulated by a cut (five longitudinal and five transverse to fibre orientation). Eleven tissues removed two weeks after occlusion-reperfusion infarction were also studied. Isochronal activation maps were constructed from extracellular and intracellular recordings and vector loops formed by summing two orthogonally recorded bipolar electrograms were used to indicate the direction of cardiac activation.Results:In the cut model, electrograms recorded from over the anatomical barrier were usually normal or showed double potentials but could occasionally be fractionated. Isochronal activation maps obtained from extracellular recordings were able to identify five of five anatomical barriers transverse to, but only one of five barriers longitudinal to, fibre orientation. The direction of cardiac activation indicated by vector loops identified conduction block in all 10 preparations. In 11 tissues removed from canine ventricles with experimental myocardial infarction, microelectrode recordings were used to characterise regions as either slow conduction or conduction block. Isochronal activation patterns obtained from extracellular recordings generally showed impulses proceeding through zones of conduction and around zones of conduction block but disagreed with the results of microelectrode impalements in two of 11 cases. Electrogram morphology was also not always able to distinguish slow conduction from block. The direction of cardiac activation determined by vector mapping accurately characterised all regions of tissue as showing either slow conduction or conduction block.Conclusions:Limited regions of conduction block or slow conduction are frequently present in epicardial tissues removed from experimental myocardial infarction. The morphology of extracellular electrograms and isochronal activation mapping performed from extracellular recordings is often but not always able to distinguish slow conduction from conduction block. Vector mapping is useful in distinguishing slow conduction from conduction block in these situations and may help evaluate myocardial conduction patterns.Cardiovascular Research1994;28:259-269