Suzuki S, Araki J, Morita T, Mohri S, Mikane T, Yamaguchi H, Sano S, Ohe T, Hirakawa M, Suga H
Department of Physiology II, Okayama University Medical School, Okayama, 700-8558, Japan.
Am J Physiol. 1998 Nov;275(5):H1513-9. doi: 10.1152/ajpheart.1998.275.5.H1513.
We recently found that contractility (Emax) of an individual irregularly arrhythmic beat in electrically induced atrial fibrillation (AF) is reasonably predictable from the ratio of the preceding beat interval (RR1) to the beat interval immediately preceding RR1 (RR2) in the canine left ventricle. Moreover, the monotonically increasing relation between Emax and the RR1-to-RR2 ratio (RR1/RR2) passed through or by the mean arrhythmic beat Emax as well as the regular beat Emax at RR1/RR2 = 1. We hypothesized that this Emax-RR1/RR2 relation during irregular arrhythmia could be attributed to the basic characteristics of the mechanical restitution and potentiation. To test this, we adopted a known comprehensive equation describing the force restitution and potentiation as a function of two preceding beat intervals and simulated contractilities of irregular arrhythmic beats with randomized beat intervals on a computer. The simulated Emax-RR1/RR2 relation reasonably resembled the one that we recently observed experimentally, supporting our hypothesis. We therefore conclude that the primary mechanism underlying the varying contractilities of irregular beats in AF is mechanical restitution and potentiation.
我们最近发现，在犬类左心室中，通过电诱导心房颤动（AF）产生的单个不规则心律失常搏动的收缩性（Emax）可以根据前一个搏动间隔（RR1）与紧接RR1之前的搏动间隔（RR2）的比值合理预测。此外，Emax与RR1与RR2的比值（RR1/RR2）之间的单调递增关系穿过或经过平均心律失常搏动Emax以及RR1/RR2 = 1时的规则搏动Emax。我们假设，这种不规则心律失常期间的Emax - RR1/RR2关系可归因于机械恢复和增强的基本特征。为了验证这一点，我们采用了一个已知的综合方程，该方程将力恢复和增强描述为两个前一个搏动间隔的函数，并在计算机上模拟了具有随机搏动间隔的不规则心律失常搏动的收缩性。模拟的Emax - RR1/RR2关系与我们最近实验观察到的关系合理相似，支持了我们的假设。因此，我们得出结论，AF中不规则搏动收缩性变化的主要机制是机械恢复和增强。
