【摘要】 为探讨下体负压下的心率变异变化及其与血液动力学指标的关系，４０名健康男性参加了下体负压实验。用Ｈｏｌｔｅｒ记录了受试者Ｖ５导联心电图，并进行了心率变异（ＨＲＶ）分析；用超声多谱勒技术测量了ＳＶ、ＣＯ。结果表明：在ＬＢＮＰ过程中两组受试者均出现了ＨＲＶ的降低，尤以高频谱质量（ＨＦ）降低显著。ＬＦ／ＨＦ在ＬＢＮＰ过程中呈升高趋势，耐力低者的ＬＦ／ＨＦ升高比耐力良好者明显。提示：晕厥前症状的发生可能是由于ＬＢＮＰ强度的增加，ＳＶ降低到一定程度时，交感神经活性增加达到极限，突然出现交感缩血管活动的撤除而致。ＬＢＮＰ耐力不同，可能是由于心脏射血功能和自主神经系统两方面的差异造成的。更多还原

【Abstract】 In order to assess the changes of HRV in relation to hemodanymic responses to LBNP,40 healthy male volunteers were exposed to progressively increasing LBNP.Changes of SV,CO and BP were measured and HRV was analyzed. Thirty-four subjects(Group A, with good tolerance)were able to tolerate all stages of LBNP, and other 6 subjects(Group B, with poor tolerance)showed presyncopal signs and symptoms during the last 5min of LBNP exposure. In both groups, HRV、SV、CO decreased significantly during LBNP. Group B had lower HRV、SV、CO than group A pre- LBNP,during- LBNP and post-LBNP. The LF/HF ratio increased during LBNP in both groups, but increased more apparently in group B than group A at -6.7 kPa LBNP. The results showed that,when SV decreased to a certain degree, the sympathetic activity increased to the utmost. The onset of presyncopal signs could be attributed to the rapid withdrawl of sympathetic tone, and LBNP tolerance of a subject is closely related to both ejecting capability of the heart and the function of autonomic nervous system.更多还原