Differential laws of left ventricular isovolumic pressure fall.
Differential laws of left ventricular isovolumic pressure fall.
复制标题
左室等容压下降的微分规律。
DOI：
10.33549/physiolres.930082
复制
发表时间：
2002
影响因子：
2.1
通讯作者：
Sfj Langer
中科院分区：
文献类型：
--
作者：
Sfj Langer
An attempt has been made to test for a reliable method of characterizing the isovolumic left ventricular pressure fall in isolated ejecting hearts by one or two time constants, tau. Alternative nonlinear regression models (three- and four-parametric exponential, logistic, and power function), based upon the common differential law dp(t)/dt = - [p(t)-P ]/ tau(t) are compared in isolated ejecting rat, guinea pig, and ferret hearts. Intraventricular pressure fall data are taken from an isovolumic standard interval and from a subinterval of the latter, determined data-dependently by a statistical procedure. Extending the three-parametric exponential fitting function to four-parametric models reduces regression errors by about 20-30%. No remarkable advantage of a particular four-parametric model over the other was revealed. Enhanced relaxation, induced by isoprenaline, is more sensitively indicated by the asymptotic logistic time constant than by the usual exponential. If early and late parts of the isovolumic pressure fall are discarded by selecting a subinterval of the isovolumic phase, tau remains fairly constant in that central pressure fall region. Physiological considerations point to the logistic model as an advantageous method to cover lusitropic changes by an early and a late tau. Alternatively, identifying a central isovolumic relaxation interval facilitates the calculation of a single ("central") tau; there is no statistical justification in this case to extend the three-parametric exponential further to reduce regression errors.
不均匀性和体积负荷独立影响等容松弛率。
DOI：
10.1152/ajpheart.1989.257.6.h1927
发表时间：
1989
期刊：
The American journal of physiology
影响因子：
--
作者：
Gillebert,TC;Lew,WY
通讯作者：
Lew,WY
人类心力衰竭心室压力松弛评估的比较：对负荷和药物敏感性分析的定量影响。
影响因子：
24
作者：
Senzaki,H;Fetics,B;Chen,CH;Kass,DA
通讯作者：
Kass,DA