Bergman S A, Hoffler G W, Johnson R L, Wolthuis R A
Aviat Space Environ Med. 1976 Apr;47(4):359-62.
After space flight of 59 d, Skylab 3 astronauts were stressed with lower body negative pressure (LBNP). During this stress procedure vectorcardiograms, pneumograms, phonocardiograms, and carotid pulse tracings were monitored and recorded onto analog tape. Accepted techniques were used to measure the intervals of systole. The postflight results were compared to multiple preflight tests and each of the three crewmen served as his own control. Immediately postflight, there were elevations in heart rate and blood pressure in response to a fixed level (-50 mm Hg) of LBNP. Total electromechanical systole, (Q-S2) I, was unchanged. Ejection time index (ETI) was depressed at rest and during stress, while pre-ejection period was elevated compared with preflight values. Systolic time intervals (STI) were within preflight limits after 1 month on earth in all crewmen. Resting STI returned sooner than did stressed STI. The magnitude and direction of STI in the postflight period were similar to those obtained from patients with moderate heart disease, although signs and symptoms were absent in the astronauts. However, the abnormality of the stressed STI persisted after both blood volume repletion and lowered afterload. These findings suggest a compromise in cardiac function, peripheral circulatory integrity, or both after exposure to long-duration space flight, and are consistent with findings reported after 3 weeks of absolute bedrest.
在进行了59天的太空飞行后，“天空实验室3号”的宇航员接受了下体负压（LBNP）应激测试。在这个应激过程中，监测了矢量心电图、呼吸图、心音图和颈动脉脉搏描记图，并记录在模拟磁带上。采用公认的技术测量收缩期的间期。将飞行后的结果与多次飞行前测试进行比较，三名机组人员中的每一个人都作为自己的对照。飞行后立即出现心率和血压升高，以应对固定水平（-50毫米汞柱）的下体负压。总机电收缩期（Q-S2）I没有变化。射血时间指数（ETI）在休息时和应激期间降低，而射血前期与飞行前值相比升高。所有机组人员在地球上停留1个月后，收缩期时间间期（STI）在飞行前的范围内。静息STI恢复得比重症STI更快。尽管宇航员没有症状和体征，但飞行后期STI的幅度和方向与中度心脏病患者相似。然而，在补充血容量和降低后负荷后，应激STI的异常仍然存在。这些发现表明，在长时间太空飞行后，心脏功能、外周循环完整性或两者都受到了损害，这与绝对卧床3周后报告的结果一致。
