摘要
心脏收缩释放的能量(作功)是心肌纤维长度的函数,或谓心脏作功是心室舒张末期容积(EDV)的函数,即著名的Frank-Starling心脏定律,被认为是心脏作功的规律的正确表达。众所周知,对于一个力,当在这个力的方向上没有位移时是不作功的。在心室舒张末期,心脏尚未开始收缩,还没有力作功,因此,心脏作功和EDV之间没有函数关系。在心脏收缩射血的作功期,通常,每搏功(W)用射血压力(P)与射血容积(V)的乘积表达,即W=P×V。而射血容积(V)又等于舒张末期容积(EDV)减去收缩末期容积(ESV),所以W=P×(EDV-ESV)。这是我们都公认的计算心脏每搏射血作功的公式。在该公式中,W,P,EDV和ESV几个参数之间的数学关系清楚地表明了W不一定随EDV的增加而增加,也不一定随EDV的减小而减小:W和EDV之间没有函数关系。在这里,笔者仅从心脏作功的生物数学角度确认:Frank-Starling心脏定律不是一个真实的定律。
Objective The theory that the energy of cardiac contraction（cardiac work,or heart working） is a function of the length of the muscle fiber（the end-diastolic volume,EDV） is known as the Frank-Starling law of the heart,which is reputed as the law of the cardiac work,and has been esteemed as trustworthy.This paper tests the truthfulness of the law from a new perspective of bio-physics and bio-mathematical relationship on the heart working.We know that a force does not do work when there is no displacement in the direction of this force.At a stage of the EDV,the heart has not yet begun its contraction（the length of myocardial fibers and the EDV have not changed）,there is no systolic force doing work at all,and there is no functional relationship between the cardiac work and the initial length of myocardial fibers（EDV）.At a stage of the contraction,generally,the heart working（W） is represented by the ejection of a volume（V） of blood under a pressure（P）.The W during each contraction is calculated by multiplying the V of blood ejected by the P： W=P×V. Because the V is equal to the EDV minus the ESV,a formula was derived as： W=P×（EDV-ESV）. That formula has been accepted ever since unanimously and universally.Nevertheless,viewed from the bio-mathematical relationship among the parameters W,P,EDV and ESV in the formula,it can be seen that there is no such functional relation between the W and the EDV.Here,the authors of this paper affirm that the Frank-Starling law of the heart is a failure to express the objective condition of the heart working from the biomathematic angle of the cardiac work,and it is not a true law.
出处
《西部医学》
2011年第9期1634-1636,1640,共4页
Medical Journal of West China
