Electrophysiological and anatomic heterogeneity in evolving canine myocardial infarction.
Electrophysiological and anatomic heterogeneity in evolving canine myocardial infarction.
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犬心肌梗塞演变中的电生理学和解剖学异质性。
DOI：
10.1111/j.1540-8159.2000.tb00904.x
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Kadish,AH
中科院分区：
文献类型：
--
作者：
Horvath,G;Racker,DK;Goldberger,JJ;Johnson,D;Jain,S;Kadish,AH
虽然心肌梗死后电生理特性的异质性增加，但这种异质性的程度尚未得到很好的定量，其与梗死后发生的组织学变化的关系尚未得到仔细研究。本研究的目的是检验这一假设，即在愈合犬梗死的电生理特性的改变与特定的组织学变化。结扎冠状动脉左前降支造成实验性心肌梗死。六只狗用作对照，六只在梗塞后5天进行研究，六只在梗塞后8周进行研究。使用多电极斑块在左心室前壁的112个部位测定起搏阈值、有效不应期和激动-恢复时间。评估了传导速度、传导异质性指数（传导障碍的一种测量方法）和斑块下的肌外膜的组织学。两个梗死组的有效不应期和激活-恢复时间更长，在亚急性组中最显著。在亚急性梗死中，存在显著的复极后不应性。与对照组和亚急性梗死组相比，愈合梗死组的传导速度降低，传导异质性指数升高。兴奋性和复极的分散与更广泛的局部瘢痕形成有关。心肌纤维角度的离散度与传导异质性指数相关。在假手术动物中也观察到了在梗死动物中观察到的部分但非全部电生理学变化。因此，复极和不应期的异质性在心肌梗死的亚急性期最大，并且与局部细胞死亡的程度相关。相反，传导障碍在梗死愈合时最严重，并与心肌纤维紊乱有关。
Although the heterogeneity of electrophysiological properties is increased after myocardial infarction, the degree of this heterogeneity has not been well quantitoted and its relationship to the histoslogical changes that occur after infarction has not been carefully examined. The purpose of the present study was to test the hypothesis that alterations in electrophysiological properties in healing canine infarction are related to particular histological changes. Experimental infarction was produced by left anterior descending coronary ligation. Six dogs were used as controls, six were studied 5 days following, and six were studied 8 weeks following infarction. Pacing thresholds, effective refractory periods, and activation‐recovery times were determined at 112 sites on the anterior left ventricle using a multiple electrode plaque. Conduction velocity, conduction‐heterogeneity index—a measure of conduction disturbance—and histology of the epimyocardium underlying the plaque were assessed. The effective refractory periods and activation‐recovery times were greater in both infarction groups, most prominently in the subacute group. In subacute infarction, significant postrepolarization refractoriness was present. In healed infarction, conduction velocity was decreased and the conduction‐heterogeneity index was increased compared to controls and subacute infarction. Dispersion of excitability and repolarization was associated with more extensive local scarring. Dispersion of myocardial fiber angles was associated with the conduction‐heterogeneity index. Some but not all of the electrophysiological changes noted in the animals with infarction were also seen in sham operated animals. Thus, heterogeneity in repolarization and refractoriness is greatest in the subacute phase of myocardial infarction and is associated with the extent of local cell death. In contrast, disturbances in conduction are greatest in healed infarction and associated with disarray of myocardial fibers.