Hori M, Inoue M, Fukunami M, Kitakaze M, Ishida Y, Tsujioka K, Nakajima S, Kitabatake A, Abe H
Cardiovasc Res. 1985 Oct;19(10):649-54. doi: 10.1093/cvr/19.10.649.
The afterload dependency of relaxation rate was reappraised in isolated canine hearts both in isovolumic and isobaric contractions by using the reliable exponential method in which the asymptote LV pressure (P chi) is variable. This method provided a closer correlation (r = 0.999 +/- 0.001) between the measured LV pressure decay and the model estimate than the semilogarithmic method assuming P chi = 0 (r = 0.992 +/- 0.001). Time constants of isovolumic LV pressure decay obtained by the exponential method demonstrated a significant (p less than 0.01) decrease during volume loading both in isovolumic and isobaric contractions, indicating that the relaxation rate is augmented as afterload increases. In contrast, if we assume P chi = 0, the time constant of LV pressure decay was independent of peak LV pressure as previously reported. Thus, we conclude that the load insensitive relaxation rate implied by the semilogarithmic method (P chi = 0) may be erroneous due to an invalid assumption, ie, P chi = 0, but the relaxation rate is augmented as afterload increases both in isovolumically contracting and isobarically ejecting isolated canine hearts.
通过使用可靠的指数方法（其中左心室压力渐近值（P chi）是可变的），在等容收缩和等压收缩的离体犬心脏中重新评估了舒张速率的后负荷依赖性。与假设P chi = 0的半对数方法（r = 0.992 +/- 0.001）相比，该方法在测量的左心室压力衰减与模型估计之间提供了更紧密的相关性（r = 0.999 +/- 0.001）。通过指数方法获得的等容左心室压力衰减的时间常数在等容收缩和等压收缩期间的容量负荷过程中均显示出显著（p <0.01）下降，表明舒张速率随着后负荷增加而增加。相比之下，如果我们假设P chi = 0，左心室压力衰减的时间常数与左心室峰值压力无关，如先前报道的那样。因此，我们得出结论，半对数方法（P chi = 0）所暗示的负荷不敏感舒张速率可能由于无效假设（即P chi = 0）而有误，但在等容收缩和等压射血的离体犬心脏中，舒张速率均随着后负荷增加而增加。
