The Effect Of Respiratory Frequency On Rabbit Heart Rate Variability

ObjectiveTo observe the effects of respiratory frequency (RF) on components offrequency spectra of rabbits heart rate variability (HRV). Compare and discussthe results of tHRV and eHRV analysis.Methods18healthy male Japanese rabbits were selected. The rabbits model ofcontroll respiratory was established. ECG, instant blood pressure andrespiratory waveform under different respiratory frequency(RF)(40bpm,50bpm,60bpm) were recorded synchronously via SKY-A4(a three channelelectrophysiolograph); HRV＆BRS2.0–a HRV analysis system was used toobserve the shift of high frequency peak(HFP), and to analyze power spectradensity(PSD). Two different analysis methods[tHRV(traditional heart ratevariability) and tHRV(traditional heart rate variability)] were adopted to analyzePSD. Observe the relationship between respiratory and RRI cyclicalchange.Comparisons between the results of the two methods were made.Results1.RRI cyclical change coincided with the respiratory cycle.2.ventilation ratecould affect the amplitude of RRI cyclical change. Compared with50bpm,40bpm could increase the amplitude and60bpm could decrease the amplitudeof cyclical change.3.High frequency peak of HRV and respiratory were locatedat the same frequency. High frequency peak of50bpm was located at the junction between LF and HF. Compare50bpm, respiratory frequency of40bpmwould shift the high frequency peak to left, and the total high frequency peakwould be located within the rage of LF.60bpm would shift it to right, and totallylocated within the HF range.4.Compare tHRV analysis with eHRV analysis:tHRV results: compare with HF, HFnorm,LF/HF of respiratory frequency of50bpm, HF, HFnorm of60bpm would be increased(HF P<0.01,HFnorm P<0.05),LF/HF would be decreased(P<0.01). compare withHF,HFnorm,LF,LFnorm,LF/HF of respiratory frequency of50bpm, HF、HFnormof40bpm were decreased, LF,LFnorm were increased, LF/HF wasincreased(P<0.01). eHRV analysis:There was no statistical significance wasfind in the HRV frequency spectra component between different ventilation rate.Conclusion1.The RRI cyclical change attribute to respiratory was respiratory sinusArrhythmias, which constitute the essential component of HRV.2.Respiratory frequency could shift high frequency peak, low respiratoryfrequency could shift high frequency peak to left, high respiratory frequencycould shift it right.3.ralatively low respiratory frequency could shift high frequency peak to LFrange, which may attribute the fault analysis of tHRV, eHRV could exclude thiseffect.