Fiser B, Janík P
Physiol Bohemoslov. 1982;31(5):401-6.
The decrease in the rate of relaxation of the myocardium during ischaemic impairment of metabolic processes is accompanied by a decrease in the size of contraction. If we stimulate the ischaemic heart with irregularly distributed pulses we can achieve, by an extrasystolic potentiation mechanism, isolated contractions. If we stimulate the ischaemic heart with irregularly distributed pulses we can achieve, by an extrasystolic potentiation mechanism, isolated contractions of the same size as average contractions in normal perfusion. When comparing the relaxation of such contractions in 15 perfused rabbit hearts, we found a linear correlation between the relaxation rate and the size of the contractions. If we relate to relaxation rate to contraction size, the relaxation rate in early ischaemia (1 min after stopping perfusion) is thus in most cases normal, despite the marked decrease in the size of the contractions. The size of the contractions of the ischaemic mammalian myocardium thus seems to diminish before relaxation (which is likewise energy-dependent) is affected.
在代谢过程缺血性损害期间，心肌松弛速率的降低伴随着收缩幅度的减小。如果用分布不规则的脉冲刺激缺血心脏，我们可以通过期外收缩增强机制实现孤立收缩。如果用分布不规则的脉冲刺激缺血心脏，我们可以通过期外收缩增强机制实现与正常灌注时平均收缩幅度相同大小的孤立收缩。在比较15个灌注兔心脏中此类收缩的松弛情况时，我们发现松弛速率与收缩幅度之间存在线性关系。因此，如果将松弛速率与收缩幅度相关联，尽管收缩幅度明显减小，但在大多数情况下，早期缺血（停止灌注后1分钟）时的松弛速率是正常的。因此，缺血哺乳动物心肌的收缩幅度似乎在松弛（这同样依赖能量）受到影响之前就已减小。
