头高位倾斜实验对高血压病患者心率变异性的影响

Effects of head-up tilt on heart rate variability of hypertension patients

目的 :探讨高血压病患者心血管自主神经调节功能的变化规律 ,为高血压病的诊断及防治提供新的科学依据 .方法 :采用AR谱分析方法对 1 7例高血压患者和 1 7例血压正常者在平卧及头高位倾斜 75°时的短时程心率变异性(HRV)信号进行分析 .结果 :①高血压患者的总功率 (TP) ,低频功率 (LF) ,高频功率 (HF) ,归化高频成分 (HFn)与血压正常者比较均显著降低 (P <0 .0 1 ) ;归化低频成分 (LFn) ,低频功率与高频功率的比值 (LF/HF)显著增加 (P <0 .0 1 ) ;②在头高位倾斜 75°的条件下 ,高血压患者HRV谱指标TP ,HF ,LF ,LF/HF显著降低 (P <0 .0 1 ) ,HFn显著升高 (P <0 .0 1 ) ,LFn显著下降 (P <0 .0 1 ) ;③高血压患者在 75°头高位倾斜时 ,其HFn较平卧状态时显著下降 (P <0 .0 5 ) ,LFn显著增加 (P <0 .0 5 ) .结论 :高血压患者心血管自主神经调节功能发生明显异常 ,表现为平卧位时交感神经传出调制活动亢进 ;而在头高位倾斜应激时 ,自主神经对心血管功能的调节能力降低 .

AIM: To explore the changes in cardiac autonomic regulation of hypertension patients during head up tilt. METHODS: Autoregressive (AR) spectral analysis was used to analyze the heart rate variability (HRV) of 17 hypertension patients and 17 age matched healthy subjects during supine and +75° head up tilting. RESULTS: ① The total power (TP), low frequency (LF), high frequency (HF), spectral indices normalized high frequency component (HFn) of HRV in hypertension patients significantly deceased ( P <0.01), whereas the normalized low frequency component (LFn) and LF/HF significantly increased ( P < 0.01). ② With head up tilt for 15 min, TP, LF, HF, LF/HF and LFn significantly decreased ( P <0.01), while HFn was markedly elevated ( P <0.01). ③ With head up tilt for 15 min, HFn of hypertension patients significantly decreased while LFn increased, compared with that of supine control ( P <0.05). CONCLUSION: The cardiovascular autonomic regulation of hypertension patients has significant changes, including an attenuated cardiac vagal, enhanced sympathetic activity in supine position and a significant impairment of cardiac autonomic response during head up tilting.