心拍リズムに対する中枢機構

A CLINICAL STUDY OF CENTRAL ACTIONS ON HEART RATE

はじめに

　正常人の心臓の拍動は洞結節固有のリズムできまり，その頻度すなわち心拍リズムは正常人では安静時には規則正しいのであるが，精密に調べるとわずかながらたえず変化している。つまり呼吸性不整脈がみられる。このように心臓は自動性により活動を営んでいるが一般内臓と同様に自律神経により調節をうけている。さらに他の神経活動や血液の性状その他の要因をうけて心臓の活動リズムは変化している^10）。

　近年，脳幹の機能を循環，呼吸の面からとらえる試みがなされており，その1つの指標として心拍リズムがとり上げられている。そこで心拍リズムを種々の脳障害を示す症例について記録し，脳障害の部位ならびに他の脳幹機能との相関を検討した。

Continuous recording of the heart beats were examined in 26 patients with various lesions of the central nervous system and in eleven healthy subjects. EEG, electromyogram, ocular movements and respiration were recorded simultaneously. The correlation between the location of lesions and alterations in heart rate were specifically inves-tigated. The results obtained were as follows.

1. The changes of heart rate were classified mainly into 3 groups, such as normal type, with-out spontaneous fluctuation of heart rate and type with slow oscillation of the base line and/or dis-turbance of respiratory arrhythmia.

2. The changes of heart rate were well corre-lated with the location of lesions. Heart rate in cases with lesions of the cerebral hemisphere and the hypothalamus showed normal type. Slow os-cillations of the base line and/or disturbance of respiratory arrhythmia were observed in cases with lesions of "cérveau isolé". No spontaneous fluc-tuation of heart rate was noted in a case with lesion of "encéphale isolé".

3. It is concluded that the main factors influ-encing on heart rate might be impulses from the respiratory center to the cardioinhibitory center in the medulla. The alterations of heart rate were not directly influenced by EEG, horizontal eye movements, eye blinking, disturbance of conscious-ness and phenomenon of the increased intracranial pressure.