Uno K
Department of Medicine, School of Medicine, Keio University, Tokyo, Japan.
Am Heart J. 1991 Dec;122(6):1694-700. doi: 10.1016/0002-8703(91)90288-s.
The aim of this study is to investigate the correlation between pulsus alternans and changes in regional myocardial contraction on the ST segment of the epicardial electrocardiogram (ECG) in open-chest dogs with coronary flow reduction and pacing. With flow reduction and pacing, alternation of regional contraction appeared primarily in shortening of the end-systolic length, and secondly in elongation of the end-diastolic length. Regional mechanical alternans was observed along with alternation of the ST segment of the epicardial ECG and was followed by pulsus alternans in some dogs. When adenosine triphosphate (ATP) content was measured at the end of the experiment, its level was preserved in dogs with pulsus alternans following regional mechanical alternans more than in those with regional mechanical alternans alone. We concluded that regional mechanical alternans is caused by the alternate changes in intrinsic contractility, probably due to alternations of Ca++ transients, since it was accompanied by ST electrical alternans. In addition, pulsus alternans might be beneficial to ischemic myocardium by causing a decrease in the consumption of high energy phosphates.
本研究旨在探讨在开胸犬冠状动脉血流减少及起搏情况下，脉压交替与心外膜心电图（ECG）ST段上局部心肌收缩变化之间的相关性。随着血流减少及起搏，局部收缩交替主要表现为收缩末期长度缩短，其次为舒张末期长度延长。局部机械性交替与心外膜ECG的ST段交替同时出现，部分犬随后出现脉压交替。实验结束时测量三磷酸腺苷（ATP）含量，与仅出现局部机械性交替的犬相比，在局部机械性交替后出现脉压交替的犬其ATP水平得以维持。我们得出结论，局部机械性交替是由内在收缩性的交替变化引起的，可能是由于Ca++瞬变的交替，因为它伴有ST段电交替。此外，脉压交替可能通过降低高能磷酸盐的消耗而对缺血心肌有益。
