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调节分散解释了心律失常的脆弱性在心脏过早刺激期间的变化
K R Laurita1, S D Girouard, F G Akar
1Departments of Medicine and Biomedical Engineering and The Cardiac Bioelectricity Research and Training Center, Case Western Reserve University, Cleveland, Ohio, USA. KLR2@po.cwru.edu
Circulation
|December 16, 1998
概括
过早的心脏刺激可以改变再极化梯度,影响对心室的易感性. 这项研究揭示了由早发心跳引起的心律失常的新机制.
科学领域:
- 心血管电生理学 心血管电生理学
- 心律失常的机制 心律失常的机制
- 计算生物学 计算生物学
背景情况:
- 过早的刺激可以调节心室再极化 (调节的分散) 的空间梯度,这是由于异质的细胞电生理学.
- 调制分散在心脏电动不稳定性中的特定作用仍然在很大程度上是未知的.
研究的目的:
- 调查过早刺激诱导的复极化梯度变化是否是控制对心律失常敏感性的关键机制.
- 为了确定过早刺激,再极化分散和心室的风险之间的关系.
主要方法:
- 从Langendorff浸透的几内亚猪心脏中的128个心室部位的同时光学作用电位记录.
- 在基线节奏 (S1) 后,在不同的S1S2合间隔中引入单个过早刺激 (S2).
- 在S2节拍的T波期间使用修改的心室动值 (VFT) 评估心律失常的脆弱性.
主要成果:
- 将S1S2间隔缩短到中间值,可使复极化梯度降低51%,动脆弱性降低73%.
- 进一步缩短S1S2间隔,再极化梯度比基线增加了54%.
- 再极化梯度的增加与对心室动的脆弱性增加了37%.
结论:
- 通过单个过早的刺激对回极化梯度的调节显著影响了对心室的脆弱性.
- 这一发现表明,在过早的心脏刺激过程中,心律失常基质的发展有着一种新的机制.
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