STUDIES OF AUTONOMIC CONTROL OF THE HEART IN YOUNG PATIENTS WITH BORDERLINE HYPERTENSION USING SYSTEMS ANALYSIS
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概要
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To evaluate disorders of the autonomic nervous system's control of the heart in young patients with borderline hypertensionm the effects of propranolol and/or atropine on heart rate at rest, after postural stimulation, and during exercise were studied in 16 young hypertensive subjects and 13 age-matched normotensive subjects. Six parameters featuring the dynamic response of heart rate to two-step exercise were determined from the characteristics on Bode and vector diagrams which were obtained by a frequency analysis of the heart rate response to exercise. Hypertensive subjects exhibited an increased resting heart rate and decreased intrinsic heart rate when compared with those of normotensive subjects. The ratio of sympathetic to vagal activity, which controls resting heart rate, was calculated to be 2:3 in hypertensives and 1:9 in normotensives. This ratio in response to changing posture was 2:1 in hypertensives and 3:2 in normotensives. Hypertensive subjects exhibited increased parameters α, T_1, and T_2 when compared with normotensives. Differences in the six parameters between hypertensives and normotensives were most striking in the experiment following parasympathetic blockade. The ratio of sympathetic to parasympathetic activity, which controls the steady-state increment of heart rate during exercise, was calculated to be 1:1 in hypertensives and 1:2 in normotensives. Young patients with labile hypertension have a disproportion of sympathetic and vagal activities with the sympathetic nervous system playing a predominant role in controling heart rate under various conditions.
- 名古屋市立大学の論文
- 1977-02-28