Loeppky J A, Greene E R, Hoekenga D E, Caprihan A, Luft U C
J Appl Physiol Respir Environ Exerc Physiol. 1981 Jun;50(6):1173-82. doi: 10.1152/jappl.1981.50.6.1173.
A 3.0 MHz pulsed Doppler echocardiography was used to estimate instantaneous stroke volume (SV) and cardiac output (Q) in eight men during steady-state supine (S) and upright (U) exercise at 300 kpm/min. The mean transients in heart rate (HR), SV, and Q for the first 20 s of exercise in each posture were then determined. Center-line blood velocities were obtained in the ascending aorta with the transducer positioned manually in the suprasternal notch. Mean supine values for SV and Q at rest and exercise were 111 ml and 6.4 1/min and 112 ml and 9.71/min, respectively. The corresponding results for U were 76 ml and 5.61/min and 92 ml and 8.41/min, respectively. These values compare favorably with previous studies utilizing invasive procedures. The transient response of Q following the onset of exercise in U was about twice as fast as in S because of the rapid and almost immediate upsurge in SV. In S, only HR served to augment Q, as SV initially fell. The faster rise in aortic flow in U with exercise represented an additional volume (184 ml) of blood passing through the aorta compared with S in the first 20s. This must be related to the rapid mobilization of pooled venous blood from the leg veins during U.
采用3.0兆赫脉冲多普勒超声心动图，对8名男性在300千帕米/分钟的稳态仰卧位（S）和直立位（U）运动期间的瞬时每搏输出量（SV）和心输出量（Q）进行评估。然后确定每个姿势运动开始后前20秒内心率（HR）、SV和Q的平均变化情况。通过将换能器手动置于胸骨上切迹来获取升主动脉的中心线血流速度。仰卧位静息和运动时SV和Q的平均值分别为111毫升和6.4升/分钟，以及112毫升和9.7升/分钟。直立位的相应结果分别为76毫升和5.6升/分钟，以及92毫升和8.4升/分钟。这些值与先前使用侵入性程序的研究结果相比具有优势。由于SV迅速且几乎立即上升，直立位运动开始后Q的瞬时反应速度约为仰卧位的两倍。在仰卧位时，由于SV最初下降，只有心率起到增加Q的作用。与仰卧位相比，直立位运动时主动脉血流更快上升，在前20秒内通过主动脉的额外血量为184毫升。这一定与直立位时腿部静脉中汇集的静脉血快速动员有关。
