HEART-RATE AND BLOOD-PRESSURE VARIABILITIES DURING GRADED HEAD-UP TILT
HEART-RATE AND BLOOD-PRESSURE VARIABILITIES DURING GRADED HEAD-UP TILT
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DOI：
10.1152/jappl.1995.78.1.212
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发表时间：
1995-01-01
影响因子：
3.3
通讯作者：
HAYANO, J
中科院分区：
文献类型：
--
作者：
MUKAI, S;HAYANO, J
本文研究了12名正常人（年龄19-27岁）在频率控制呼吸（0.25Hz）条件下心率（HR）和血压（BP）变异性频率成分对分级头高位倾斜技术引起的自主神经活动进行性变化的反应。在低水平倾斜（0-30度）期间，R-R间期不变，HR变异性的高频（HF; 0.25 Hz）分量的振幅仅显示出轻微的不显著降低。心率变异性低频（LF; 0.04- 0.15Hz）振幅随角度的增加而进行性增加（P < 0.05）。在高水平倾斜（30-90度）期间，RR间期和HR变异性的HF幅度随着倾斜角度的增加而进行性降低（两者P < 0.001）。HR变异性的LF幅度在倾斜角度为30度时达到峰值。当倾斜角度从0 °增加到60 °时，心率变异性的LF/HF比值和收缩压和舒张压变异性的LF幅度逐渐增加（P < 0.001），而收缩压和舒张压无变化。这些结果表明，混合的自主反应直立性应激，这被认为是由心肺和动脉压力反射机制介导的，可以区分的HR和BP变异的频率分量的变化。
We investigated the responses of the frequency components of heart rate (HR) and blood pressure (BP) variabilities to progressive changes in autonomic activity induced by the graded head-up tilt technique in 12 normal subjects (age 19-27 yr) under the condition of frequency-controlled respiration (0.25 Hz). During low-level tilt (0-30 degrees), the R-R interval was unchanged and the amplitude of the high-frequency (HF; 0.25 Hz) component of HR variability showed only a slight insignificant decrease. The amplitude of the low-frequency (LF; 0.04-0.15 Hz) component of HR variability increased progressively as the angle increased (P < 0.05). During high-level tilt (30-90 degrees), the RR interval and the HF amplitude of HR variability decreased progressively with tilt angle (P < 0.001 for both). The LF amplitude of HR variability peaked at a tilt angle of 30 degrees. The LF-to-HF ratio of HR variability and the LF amplitude of systolic and diastolic BP variabilities increased progressively as the tilt angle increased from 0 to 60 degrees (P < 0.001), although systolic and diastolic BPs were unchanged. These results suggest that mixed autonomic responses to orthostatic stress, which are thought to be mediated by both cardiopulmonary and arterial baroreflex mechanisms, can be distinguished by changes in the frequency components of HR and BP variabilities.