Hr. Ahmad et al., DYNAMIC AND STEADY-STATE RESPONSE OF HEART-RATE TO ORTHOSTATIC STRESSIN NORMOTENSIVE AND HYPERTENSIVE PREGNANT-WOMEN, European journal of obstetrics, gynecology, and reproductive biology, 66(1), 1996, pp. 31-37
We determined the dynamic and steady state responses of heart rate (HR
) to orthostatic stress (standing up) in normotensive and hypertensive
pregnant women, Using a continuous recording with servo-photosphygmog
raphy, HR response to change in posture from left lateral recumbent po
sition to standing was analysed. The subjects were divided into five g
roups comprising: Groups I, II and III: normotensive pregnant women in
each of the three trimesters of pregnancy (total n = 77); Group IV: w
omen with gestational proteinuric hypertension (GPH) in the third trim
ester (n = 16); Group V: age-matched non-pregnant normotensive control
s (n = 15), The HR reacted with a typical overshoot response to this o
rthostatic change with HR rising to a peak and then settling to a new
but higher steady state, Change in steady state HR from lying to stand
ing (delta HR), rate of rise of HR in response to standing (i.e. the a
cceleration slope (HR(on))), and rate of fall of HR after reaching the
peak (i.e. deceleration slope (HR(off))) were evaluated from standing
heart rate time curves, HR(on) in response to standing showed a downw
ard trend with gestation (ANOVA, P < 0.05) in normotensive gravida. Th
e deceleration slope (HR(off)) showed a distinct gestational age-relat
ed decrease from first to third trimester in normotensive women (ANOVA
, P < 0.01). The most striking observation was that the slope of HR(of
f) for the GPH group was significantly steeper than that of normotensi
ve women of comparable gestational age (unpaired t-test P < 0.01) and
approximated to that of the non-pregnant group. The difference in HR r
esponse between normotensive women and those with GPH in the third tri
mester suggests it may have potential as a new marker for pre-eclampsi
a.