Short-term high frequency electrostimulation (8-10 Hz) of the isolated isovolumic rat heart rapidly increased the rate of pressure rise and drop and the diastolic pressure. At the same time, the relaxation rate constant (RRC), being independent of the developed pressure, remained unaltered. These findings suggested that diastolic pressure rise was not caused by incomplete myocardial relaxation. Doxorubicin (3 μM) moderately reduced the developed pressure, but the relaxation rate constant remained unchanged. The dynamics and degree of changes in all indicators of the cardiac contractile function in high-frequency stimulation were the same as in control. It can be hypothesized that the initial effect of doxorubicin was not related to ionic transport system disturbances in cardiomyocytes.

中文翻译：

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急性多柔比星治疗背景下心脏对高频刺激的反应

离体等容大鼠心脏的短期高频电刺激 (8-10 Hz) 迅速增加了压力上升和下降的速度以及舒张压。同时，松弛速率常数 (RRC) 与发展压力无关，保持不变。这些发现表明舒张压升高不是由不完全的心肌松弛引起的。Doxorubicin (3 μM) 适度降低了产生的压力，但弛豫速率常数保持不变。高频刺激下心脏收缩功能各项指标的动态变化和变化程度与对照组相同。可以假设多柔比星的初始作用与心肌细胞中的离子转运系统紊乱无关。