Regen D M, Howe W C, Peterson J T, Little W C
Vanderbilt University School of Medicine, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615.
Heart Vessels. 1993;8(3):136-48. doi: 10.1007/BF01744798.
By fitting isovolumic phases of an ejecting beat with a model-wave function, one can predict source pressure of the ejecting beat (Sunagawa et al. Trans Biomed Eng 1980; 27:299-305), this being a major determinant of systolic performance. Prior applications of this principle have involved two assumptions: (1) that the isovolumic pressure wave is shaped like an inverted cosine wave, and (2) that duration of an isovolumic beat is the same as that of an ejecting beat. The first assumption might cause overestimation of source pressure, since an isovolumic pressure wave begins declining before the midpoint of the wave. The second assumption might cause underestimation of source pressure, since an ejecting beat is always shorter than an adjacent isovolumic beat at the ejecting beat's end-diastolic volume. Although the two errors tend to cancel, it would be more rational and accurate to use a realistic model wave shape and a realistic isovolumic beat duration. To acquire the information necessary for this, pressure and volume time courses were measured during ejecting beats and adjacent isovolumic beats in dogs under the following steady-state conditions: basal, atrial pacing at various rates, infusion of dobutamine, infusion of verapamil, coronary ligation(s), and ventricular pacing at various sites. These conditions affected the amplitude and duration of isovolumic pressure waves substantially but did not affect the shape of the waves significantly. The duration of each isovolumic beat exceeded that of the previous ejecting beat to a degree which corresponded approximately to the ejecting beat's normalized pressure reserve (source pressure minus peak ejection pressure)/(source pressure). A more accurate source-pressure prediction should be possible by use of a realistic isovolumic pressure-wave shape and by taking account of the effect of pressure reserve on contraction duration.
通过将射血搏动的等容相拟合到模型波函数，可以预测射血搏动的源压力（Sunagawa等人，《生物医学工程学报》1980年；27:299 - 305），这是收缩功能的一个主要决定因素。该原理之前的应用涉及两个假设：（1）等容压力波的形状类似于倒余弦波，以及（2）等容搏动的持续时间与射血搏动的持续时间相同。第一个假设可能会导致源压力的高估，因为等容压力波在波的中点之前就开始下降。第二个假设可能会导致源压力的低估，因为在射血搏动的舒张末期容积时，射血搏动总是比相邻的等容搏动短。尽管这两个误差往往会相互抵消，但使用实际的模型波形和实际的等容搏动持续时间会更合理和准确。为了获取为此所需的信息，在以下稳态条件下测量了犬类射血搏动和相邻等容搏动期间的压力和容积时间过程：基础状态、不同速率的心房起搏、多巴酚丁胺输注、维拉帕米输注、冠状动脉结扎以及不同部位的心室起搏。这些条件显著影响了等容压力波的幅度和持续时间，但对波的形状影响不大。每个等容搏动的持续时间超过前一个射血搏动的持续时间，其程度大致与射血搏动的标准化压力储备（源压力减去射血峰值压力）/（源压力）相对应。通过使用实际的等容压力波形并考虑压力储备对收缩持续时间的影响，应该能够进行更准确的源压力预测。
