+Gz作用下心电图QT间期的改变及其意义

Changes in QT Interval of Electrocardiogram under +Gz Acceleration and Its Significance.

目的探讨能否用 Ｑ Ｔ 间期来预测飞行员对＋ Ｇｚ 应激的反应情况。方法３７ 名空军飞行员在人用离心机上经受峰值为４ Ｇ 的正向加速度作用，根据被试者对＋ Ｇｚ 应激反应的不同，将其分成 Ａ组（ 反应良好组，ｎ ＝ １８） 、 Ｂ 组（ 反应亢进组，ｎ ＝ １４） 和 Ｃ 组（ 反应抑制组，ｎ ＝ １） 。实验结束后测量＋ Ｇｚ 作用前、中、后心电图的 Ｑ Ｔ 间期和 Ｒ Ｒ 间期，并对能够测量出 Ｑ Ｔ 间期的３３ 人（８９ ．２ ％ ） 的数据进行统计分析。结果 ＋ Ｇｚ 作用中 Ｑ Ｔ 间期和 Ｒ Ｒ 间期明显缩短， Ｑ Ｔ 间期对 Ｒ Ｒ 间期的敏感性明显增加（ 与＋ Ｇｚ 作用前比， Ｐ＜ ０ ．００１） ； Ａ 组与 Ｂ 组相比，＋ Ｇｚ 作用中 Ｑ Ｔ 间期对 Ｒ Ｒ 间期的敏感性差异显著（ Ｐ＜ ０ ．００１） ；用＋ Ｇｚ 作用中的 Ｑ Ｔ 间期和 Ｒ Ｒ 间期建立的判别方程有效，其总的判别正确率为８１ ．８ ％ 。结论＋ Ｇｚ 作用下 Ｑ Ｔ 间期的改变与自主神经均衡性的变化有关；用心电图的 Ｑ Ｔ 间期和 Ｒ Ｒ 间期通过判别方程可以预测飞行员对＋ Ｇｚ 应激的反应情况，本研究提出的指标和方法有可能在 Ｇ－ Ｌ Ｏ Ｃ 预警系统中得到应用。

Objective To define whether QT interval could be used to predict the response of pilots to +Gz stress. Method 37 pilots underwent +4 Gz acceleration on a human centrifuge.According to their responses to +Gz stress, subjects were divided into group A (good reaction group, n=18), group B (hyperfunction reaction group,n=14) and group C (inhibition reaction group,n=1). QT and RR interval were measured pre-,during and post G. The data of 33 subjects(89.2%) whose QT interval could be measured were analyzed statistically. Result During +Gz, QT and RR interval were shortened and sensitivity of QT interval to RR interval was augmented significantly (vs. pre G, P< 0.001 );group B had higher sensitivity of QT interval to RR interval during +Gz (P<0.001, as compared with group A);discrimination functions established by QT and RR interval during +Gz were efficient and their accurate judgement rate was 81.8%. Conclusion The Changes in QT interval of ECG were related to autonomic nervous imbalance under +Gz; QT interval and RR interval could be used to predict the response of pilots to +Gz stress. These suggested that the parameters and method in this study might be used in G LOC warning system.