Autonomic nervous function was evaluated by means of power spectral analysis
of heart rate variability in hospitalized patients with different circadian
blood pressure(BP) variation, ie, dipper(n33), non-dipper(n37), extreme
dipper(n26) and riser(n20). Ambulatory BP monitoring was performed
by A & D TM2425 based on a cuff-oscillometric method. Circadian BP
variation was defined in these subjects. The non-dipper, extreme dipper
and riser subjects were defined as those whose nocturnal decrease in systolic
BP was less than 10%, more than 20% and elevation of BP, as compared to
the daytime BP, respectively.
Power spectral analysis of hourly R-R intervals for 24 hours was done to
obtain the low frequency power(LF, 0.04 to 0.15 Hz) and high frequency
power(HF, 0.15 to 0.40 Hz). LF/HF ratio was considered to be an index of
sympathetic nervous activity, and HF parasympathetic nervous activity,
respectively. LF/HF was significantly lower in both riser and non-dipper
than that in dipper subjects throughout the day. In non-dipper day-night
difference of HF was smaller than in dipper and extreme dipper groups.
These findings indicated that riser and non-dipper hypertensives were characterized
by decreased physiological circadian fluctuation of autonomic functions
when compared to dipper subjects. The circadian variation of BP may be
mediated at least in part by circadian variation of autonomic nervous system
activity.
[Rinsho Byori 50 : 899`905, 2002]
*1Department of Clinical Laboratory, Tohoku University Hospital, Sendai 980-8574
yKey Wordszhypertension(ณ)Cautonomic nervous activity(ฉฅ_o)Cheart rate variability(Sฯฎ)Cblood pressure(ณ)
๓t2002N415๚E๓2002N813๚
*1kๅwใwฎa@ธC*2,3ฏ@ๅw@๒wEใwnคศีฐ๒wC
*4,5ฏ@ใwชqffw(ง980-8574 ๅไsยtๆฏหฌ1-1)
E-mail :bigkyu-thk@umin.ac.jp