Piene H, Myhre E S
Am J Physiol. 1984 Oct;247(4 Pt 2):H531-40. doi: 10.1152/ajpheart.1984.247.4.H531.
In control heart beats of six open-chest dogs we established a relationship between ventricular diameter and change in volume during systolic ejection, described ventricular mechanical performance by a time-dependent pressure-diameter relationship, and represented ventricular afterload in subsequent variably loaded test beats by aortic input impedance calculated from aortic flow and pressure. Impedance was manipulated by means of an inflatable balloon in the aorta. A computational procedure was developed which combined the independent and general descriptions of ventricle (1 and 2 above) and load (3 above) to predict the time course and mean values of aortic pressure, flow, ventricular pressure, and diameter over a broad range of aortic impedance. Predicted data were compared with those directly observed at identical impedance. High degree of accordance between predicted and observed data of stroke volume, mean aortic and mean ventricular pressure was found, but diameter shortening was less accurately predicted. Previously assessed dependency of the ventricular pressure-volume-time relationship on aortic flow and "ejection history" was also incorporated in the calculations. This caused improved prediction of the flow pulse configuration, but the quality of predictions of mean values of pressures and flow was not enhanced.
在六只开胸犬的对照心跳中，我们建立了心室直径与收缩期射血期间容积变化之间的关系，通过时间依赖性压力-直径关系描述心室机械性能，并在随后的可变负荷测试心跳中，用根据主动脉血流和压力计算出的主动脉输入阻抗来表示心室后负荷。通过在主动脉中放置一个可充气气球来控制阻抗。开发了一种计算程序，该程序结合了对心室（上述1和2）和负荷（上述3）的独立且通用的描述，以预测在广泛的主动脉阻抗范围内主动脉压力、血流、心室压力和直径的时间进程及平均值。将预测数据与在相同阻抗下直接观察到的数据进行比较。发现预测的和观察到的每搏输出量、平均主动脉压力和平均心室压力数据高度一致，但直径缩短的预测不够准确。计算中还纳入了先前评估的心室压力-容积-时间关系对主动脉血流和“射血历史”的依赖性。这使得对血流脉冲形态的预测得到改善，但对压力和血流平均值的预测质量并未提高。
