体位改变对Beagle犬心脏自主神经控制的影响

目的观察体位改变对Beagle犬心脏自主神经控制的影响。方法利用大动物无创生理遥测技术,监测清醒活动状态下雌性Beagle犬在静态姿势（lying、standing、sitting、hanging）和运动（walking）姿势下的心电图（ECG）,并用HRV功率谱分析其自主神经功能。结果在静态姿势下,Beagle犬RR间期（RRI）、RR间期的标准差SDNN（SDNN）、相邻RR间期差值平方和的均方根RMSSD（RMSSD）、相邻R-R间期差值〉50 ms的窦性个数占心搏总数的百分比pNNabs（50）（pNNabs（50））、TP总功率（TP）、VLF极低频功率（VLF）、标准化高频功率（HFnorm）均明显高于运动状态（P〈0.05,P〈0.01）,而心率（HR）、标准化低频功率（LFnorm）和低频功率/高频功率（LF/HF）平衡指数则明显低于运动状态（P〈0.05,P〈0.01）。结论不同体位姿势在静息状态下以迷走神经活动兴奋为主,相反,在运动状态下以交感神经活动兴奋为主;体位姿势改变能引起心率的变化,必然影响心脏自主神经控制能力,其主要取决于迷走神经活动强弱有关,且导致LF/HF均衡性的破坏。

Effect of Postural Changes on Autonomic Nervous Control of Heart in Beagle Dogs

Objective The aim of this study was to observe the effect of postural changes on autonomic nervous control of heart in Beagle dogs.Methods Electrocardiogram（ECG） was recorded in static posture（lying,standing,sitting and hanging） and moving posture（walking） from conscious and unrestrained female Beagle dogs using a non-invasive telemetry system,and the autonomic nervous function was investigated by power spectral analysis of heart rate variability（HRV）.Results In static postures,the RR interval,SDNN,RMSSD,pNNabs（50）,total power（TP）,very low frequency（VLF） power and normalized high frequency（HF） power were significantly higher than those in moving posture（P0.05,P0.01）,while the heart rate,normalized LF and the LF to HF ratio were significantly lowered（P0.05,P0.01）.Conclusions The parasympathetic nervous activity is dominant in static state of different postures,while sympathetic nervous activity is dominant in moving state.Postural changes can influence the heart rate and inevitably affect the cardiac autonomic nervous control.It depends on the intensity of the vagus nerve activity,and leads to the disturbance of LF/HF balance.