呼吸频率对兔心率变异频谱成分影响和校正方法

Effect of respiratory frequency on spectral components of rabbit heart rate variability and its excluding methods

摘要:

目的：探讨呼吸频率对兔心率变异（heart rate variability，HRV）频谱成分的影响和排除方法。方法：建立兔控制呼吸模型，用SKY-A4生理记录仪记录不同呼吸频率（40、50、60次/min）时心电、呼吸波形，使用HRV ＆ BRS2.0分析软件，分析呼吸频率对高频峰位置的影响，使用传统HRV（traditional heart rate variability，tHRV）和校正HRV（enhanced heart rate variability，eHRV）2种方法分析呼吸频率对HRV频谱成分的影响，比较不同方法分析结果。结果：（1）50次/min呼吸时呼吸峰在低频（low fre－quency，LF）与高频（high frequency，HF）交界处，减低呼吸频率（40次/min）呼吸峰左移至低频段，加快呼吸频率（60次/min）呼吸峰右移完全在高频段；（2）tHRV分析示：呼吸频率对总功率（total power，TP）无明显影响，对LF、LFnorm、HF、HFnorm影响具有显著性，两两比较，与基础呼吸频率50次/min相比，60次/min使HF增大（P=0.179），HFnorm增大（P=0.011），LF减小（P=0.04），LFnorm减小（P=0.001），LF/HF减小（P=0.028）；40次/min使HF、HFnorm减小，LF、LFnorm增大、LF/HF增大；（3）eHRV分析示：与呼吸频率50次/min相比，40次/min与60次/min呼吸时，LF、LFnorm、HF、HFnorm、LF/HF差异均无统计学差异。结论：呼吸频率减慢可使高频峰移至低频段致HF减小，LF增大，LF/HF增大的假象，用eHRV分析方法可排除此影响。

Abstract:

Objective：To study the effect of respiratory frequency on spectral components of rabbit heart rate variability（HRV） and to discuss how to exclude it. Methods：Totally 12 healthy male rabbits aged 4-5 months and weighting 2.5-3.0 kg were selected. Rabbit respiratory control system was established. Electrocardiograph，instant blood pressure and respiratory waveform under different respira－tory frequencies（RF）（40，50，60 times/min） were recorded synchronously via SKY-A4（a three channel electrophysiolograph）. HRV ＆ BRS2.0-a HRV analysis system was used to observe the shift of high frequency peak（HFP） and to analyze power spectra density（PSD）. Two different analysis methods were adopted to analyze PSD：traditional heart rate variability（tHRV） analysis method and enhanced heart rate variability（eHRV） analysis method. Comparison between the results of the two methods was made. Results：①the shift of HFP：HFP was located at the conjunction of low frequency（LF） segment and high frequency（HF） segment when RF 50 times/min；HFP shifted into the LF segment when RF 40 times/min；total HFP shifted to HF segment when RF 60 times/min. ②tHRV results：RF exerted no effect on total power while significantly affected LF，LFnorm，HF，HFnorm. Compared with those when RF 50 times/min，HF and HFnorm decreased（P=0.179，P=0.011）while LF，LFnorm，LF/HF increased（P=0.04，P=0.001，P=0.028） when RF 60 times/min. Compared with those when RF 50 times/min，HF and HFnorm decreased while LF，LFnorm，LF/HF increased when RF 40 times/min.③eHRV results：there was no significant difference in LF，LFnorm，HF，HFnorm，LF/HF when RF 60 times/min and RF 40 times/min compared with those when RF 50 times/min. Conclusion：RF slowing down would shift HFP to relatively low frequency，sometimes to LF segment，which would increase LF and decrease HF. Enhanced HRV analysis could exclude this influence.