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Circadian variation of haemodynamics in patients with essential hypertension
1Department of Cardiovascular Medicine, Aomori Prefectural Central Hospital, Aomori, Japan.
Abstract:
A Holter BP monitor and a noninvasive, continuous cardiac output (CO) monitor were concurrently attached to 25 middle-aged hospitalized patients with essential hypertension (EH). Blood pressure, heart rate (HR) and CO were measured every 10 minutes over 24 hours. Circadian variation of mean BP was studied. Comparison of values to the 6:00 value revealed a significant increase in mean BP during the active hours of the day. Mean BP during the sleeping hours, on the other hand, was significantly lower than during the awake hours. The circadian variations of CO and HR demonstrated similar fluctuations to those of mean BP. The circadian variation of the CO change ratio based on the 6:00 CO value was similar to that of mean BP. Circadian variation of total peripheral resistance (TPR) change ratio based on the 6:00 value demonstrated an inverse relation to the mean BP. It is suggested that the relation between TPR and CO in the circadian variation might be described as high output-low resistance.
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