Whinnery C C, Whinnery J E
USAF Academy, Colorado Springs, Colorado.
Aviat Space Environ Med. 1988 Feb;59(2):102-6.
The electrocardiographic intervals (PR, QRS, QT, and RR) before, during, and post +Gz stress were measured in 24 healthy male subjects undergoing +Gz centrifuge exposure. The PR and QRS intervals responded in a predictable manner, shortening during stress and returning to baseline resting values post-stress. The QT interval, however, was not observed to be dependent solely on heart rate. Bazett's formula, which was developed to correct for heart rate variability, did not adequately result in a homogeneous correction of the QT interval for each stress-related period. During +Gz stress, the QT was shortened, and the QTc prolonged. The QT interval remained shortened even though the heart rate returned to baseline (with the QTc undercorrected) in the post-stress period. The QT (QTc) interval variations probably reflect the effects of both heart rate and autonomic balance during and after +Gz stress, and may provide a measure of the prevailing autonomic (sympathetic or parasympathetic) tone existing at a given point associated with +Gz stress. These electrocardiographic interval changes define the normal response for healthy individuals. Individuals with exaggerated autonomic responses could be identified by comparing their responses to these normal responses resulting from +Gz stress.
在24名接受+Gz离心机暴露的健康男性受试者中，测量了+Gz应激前、应激期间和应激后的心电图间期（PR、QRS、QT和RR）。PR和QRS间期的反应符合预期，在应激期间缩短，并在应激后恢复到基线静息值。然而，QT间期并未观察到仅依赖于心率。为校正心率变异性而开发的Bazett公式，并未充分实现对每个应激相关时期QT间期的均匀校正。在+Gz应激期间，QT缩短，QTc延长。即使在应激后心率恢复到基线水平（QTc校正不足），QT间期仍保持缩短。QT（QTc）间期变化可能反映了+Gz应激期间和之后心率和自主神经平衡的影响，并可能提供一种衡量与+Gz应激相关的给定时间点存在的主要自主神经（交感或副交感）张力的方法。这些心电图间期变化定义了健康个体的正常反应。通过将个体对应激的反应与+Gz应激产生的这些正常反应进行比较，可以识别出具有过度自主神经反应的个体。
