Numata Takashi, Kishida Yuji, Jimbo Yasuhiko, Kotani Kiyoshi
Annu Int Conf IEEE Eng Med Biol Soc. 2013;2013:5377-80. doi: 10.1109/EMBC.2013.6610764.
Respiratory sinus arrhythmia (RSA) is known as an index of cardiac vagal activity and useful to evaluate the response of the cardiovascular system to external stimuli. As an external stimulation, swallowing is known to strongly affect the cardiovascular system. However, the influence of swallowing and its relation with the autonomic nervous system remain incompletely understood. In this study, since autonomic nervous control of the cardiovascular system has a circadian rhythm, we evaluated circadian changes of influence of swallowing on RSA. Measurements were conducted on healthy humans with periodic swallowing in the morning, afternoon, and evening. RSA waveforms were extracted from an instantaneous R-R Interval (RRI) as functions of the respiratory phase and the data were divided into three subsets with respiration with swallowing, one respiration after the swallowing, and normal respiration. As a result, the RSA amplitude during respiration with swallowing was larger in the morning than in the evening. In addition, the minimum RRI during respiration with swallowing was larger in the morning than in the afternoon and evening. Thus, circadian changes of influence of swallowing on the RSA amplitude are extracted and swallowing-induced tachycardia is different with different states of autonomic nervous activity. Therefore, vagal activity should largely contribute to tachycardia induced by swallowing and evaluation of circadian changes of influences of external stimuli would be useful to investigate the mechanisms of response of the cardiovascular system to external stimuli.
呼吸性窦性心律不齐（RSA）被认为是心脏迷走神经活动的一个指标，有助于评估心血管系统对外部刺激的反应。作为一种外部刺激，吞咽已知会强烈影响心血管系统。然而，吞咽的影响及其与自主神经系统的关系仍未完全了解。在本研究中，由于心血管系统的自主神经控制具有昼夜节律，我们评估了吞咽对RSA影响的昼夜变化。对健康人在早晨、下午和晚上进行定期吞咽时进行测量。从瞬时R-R间期（RRI）中提取RSA波形作为呼吸相位的函数，并将数据分为三个子集：吞咽时呼吸、吞咽后一次呼吸和正常呼吸。结果，吞咽时呼吸期间的RSA幅度在早晨大于晚上。此外，吞咽时呼吸期间的最小RRI在早晨大于下午和晚上。因此，提取了吞咽对RSA幅度影响的昼夜变化，并且吞咽诱发的心动过速在自主神经活动的不同状态下有所不同。因此，迷走神经活动应在很大程度上导致吞咽诱发的心动过速，评估外部刺激影响的昼夜变化将有助于研究心血管系统对外部刺激的反应机制。
