Ejection- and isovolumic contraction-phase wall thickening in nonischemic myocardium during coronary occlusion.
Ejection- and isovolumic contraction-phase wall thickening in nonischemic myocardium during coronary occlusion.
复制标题
冠状动脉闭塞期间非缺血心肌的射血期和等容收缩期壁增厚。
DOI：
10.1152/ajpheart.1990.258.2.h490
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Gallagher,KP
中科院分区：
文献类型：
--
作者：
Ning,XH;Zweng,TN;Gallagher,KP
开胸麻醉犬急性局部缺血时，非缺血心肌收缩增强。然而，基于最近的研究（使用中壁段长度测量），增强收缩的有效性受到质疑，这些研究报告称，大多数增强仅发生在收缩期等容收缩期（ICP），而不是收缩期的射血期（EP）。我们回顾性地评估了这一问题，使用不同的方法测量局部心肌功能，收缩壁增厚（用声纳微米测量）。在开胸麻醉的狗中，我们观察到ICP和EP壁增厚显著增加。旋闭塞时，ICP和EP增厚对总增厚的贡献平均各为50%。在左前降支闭塞时，ICP增厚占总增加的比例明显更大（71%），但EP增厚的变化也很显著（29%）。因此，在开胸犬中，我们观察到脑室内卸载的证据（即ICP增厚增加），但我们也观察到有效（EP）增厚增加。然而，在一系列有意识的狗中，我们观察到冠状动脉绕道闭塞后，总的非缺血性增厚没有显著变化。冠状动脉闭塞后急性ICP成分有统计学意义的增加，但其对总壁增厚的贡献很小。在一组在旋转闭塞后每隔2周进行研究的狗中，在闭塞后3-5天没有证据表明脑室内卸载。因此，我们得出结论，显著的脑室内卸载仅限于心肌梗死的急性期，我们认为其功能重要性在有意识的闭胸犬中小于开胸犬。
During acute regional ischemia in open-chest anesthetized dogs, contraction is augmented in nonischemic myocardium. The effectiveness of enhanced contraction, however, has been questioned based on recent studies (using midwall segment length measurements) that reported that most of the increase occurred only during the isovolumic contraction phase (ICP) and not the ejection phase (EP) of systole. We evaluated this issue retrospectively using a different means of measuring regional myocardial function, systolic wall thickening (measured with sonomicrometers). In open-chest anesthetized dogs we observed a significant increase in both ICP and EP wall thickening. With circumflex occlusion, ICP and EP thickening each contributed an average of 50% to the augmentation in total thickening. With left anterior descending occlusion, ICP thickening contributed a significantly greater proportion (71%) to the total increase, but the change in EP thickening was also significant (29%). Therefore, in open-chest dogs we observed evidence of intraventricular unloading (in that ICP thickening increased), but we also observed an increase in effective (EP) thickening. In a series of conscious dogs, however, we observed no significant change in total nonischemic thickening after circumflex coronary occlusion. There was a statistically significant increase in the ICP component acutely after coronary occlusion, but its contribution to total wall thickening was small. In a group of dogs studied at intervals for 2 wk after circumflex occlusion, there was no evidence of intraventricular unloading beyond 3-5 days postocclusion. Therefore, we conclude that significant intraventricular unloading is restricted to the acute phases of myocardial infarction, and we suggest that its functional importance is smaller in conscious closed-chest chest dogs than in open-chest dogs.