Daily Profile of Baroreflex Sensitivity and the Variability of Blood Pressure in Essential Hypertensive Patients

1981 ◽  
Vol 61 (s7) ◽  
pp. 157s-159s ◽  
Author(s):  
Jun Ogawa ◽  
Shiro Arai ◽  
Shigeo Takata ◽  
Takayuki Ikeda ◽  
Toshikazu Takabatake ◽  
...  

1. We have monitored intra-arterial pressure continuously throughout the day and analysed every beat by computer. 2. Baroreflex sensitivity (ms/mmHg) was measured four times a day (07.00, 12.00, 17.00 and 20.00 hours) in seven patients and three times a day (07.00, 12.00 and 17.00 hours) in 23 patients. The diurnal variation of baroreflex sensitivity in individual patients was 0–5.3 ms/mmHg and was not consistent. Mean baroreflex sensitivity was reduced in hypertensive patients compared with normotensive subjects. 3. A negative correlation was seen between baroreflex sensitivity and the variability of systolic blood pressure. 4. Baroreflex sensitivity was well correlated with the variability of heart rate.

1980 ◽  
Vol 59 (s6) ◽  
pp. 401s-404s ◽  
Author(s):  
G. Mancia ◽  
A. Ferrari ◽  
L. Gregorini ◽  
G. Parati ◽  
G. Pomidossi ◽  
...  

1. Intra-arterial blood pressure and heart rate were recorded for 24 h in ambulant hospitalized patients of variable age who had normal blood pressure or essential hypertension. Mean 24 h values, standard deviations and variation coefficient were obtained as the averages of values separately analysed for 48 consecutive half-hour periods. 2. In older subjects standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation and variation coefficient for heart rate were smaller. 3. In hypertensive subjects standard deviation for mean arterial pressure was greater than in normotensive subjects of similar ages, but this was not the case for variation coefficient, which was slightly smaller in the former than in the latter group. Normotensive and hypertensive subjects showed no difference in standard deviation and variation coefficient for heart rate. 4. In both normotensive and hypertensive subjects standard deviation and even more so variation coefficient were slightly or not related to arterial baroreflex sensitivity as measured by various methods (phenylephrine, neck suction etc.). 5. It is concluded that blood pressure variability increases and heart rate variability decreases with age, but that changes in variability are not so obvious in hypertension. Also, differences in variability among subjects are only marginally explained by differences in baroreflex function.


2008 ◽  
Vol 295 (3) ◽  
pp. H1150-H1155 ◽  
Author(s):  
François Cottin ◽  
Claire Médigue ◽  
Yves Papelier

The aim of the study was to assess the instantaneous spectral components of heart rate variability (HRV) and systolic blood pressure variability (SBPV) and determine the low-frequency (LF) and high-frequency baroreflex sensitivity (HF-BRS) during a graded maximal exercise test. The first hypothesis was that the hyperpnea elicited by heavy exercise could entail a significant increase in HF-SBPV by mechanical effect once the first and second ventilatory thresholds (VTs) were exceeded. It was secondly hypothesized that vagal tone progressively withdrawing with increasing load, HF-BRS could decrease during the exercise test. Fifteen well-trained subjects participated in this study. Electrocardiogram (ECG), blood pressure, and gas exchanges were recorded during a cycloergometer test. Ventilatory equivalents were computed from gas exchange parameters to assess VTs. Spectral analysis was applied on cardiovascular series to compute RR and systolic blood pressure power spectral densities, cross-spectral coherence, gain, and α index of BRS. Three exercise intensity stages were compared: below (A1), between (A2), and above (A3) VTs. From A1 to A3, both HF-SBPV (A1: 45 ± 6, A2: 65 ± 10, and A3: 120 ± 23 mm2Hg, P < 0.001) and HF-HRV increased (A1: 20 ± 5, A2: 23 ± 8, and A3:40 ± 11 ms2, P < 0.02), maintaining HF-BRS (gain, A1: 0.68 ± 0.12, A2: 0.63 ± 0.08, and A3: 0.57 ± 0.09; α index, A1: 0.58 ± 0.08, A2: 0.48 ± 0.06, and A3: 0.50 ± 0.09 ms/mmHg, not significant). However, LF-BRS decreased (gain, A1: 0.39 ± 0.06, A2: 0.17 ± 0.02, and A3: 0.11 ± 0.01, P < 0.001; α index, A1: 0.46 ± 0.07, A2: 0.20 ± 0.02, and A3: 0.14 ± 0.01 ms/mmHg, P < 0.001). As expected, once VTs were exceeded, hyperpnea induced a marked increase in both HF-HRV and HF-SBPV. However, this concomitant increase allowed the maintenance of HF-BRS, presumably by a mechanoelectric feedback mechanism.


Author(s):  
V.S. Pasko

The aim of the study was to determine the peculiarities of ABPM indices in middle-aged and elderly hypertensive patients depending on the daily BP profile. Material and methods. Indices of ambulatory blood pressure monitoring were identified in 57 middle-aged patients (45-59 years) (group I) and 43 elderly patients (60-74 years) (group II), who underwent two-week in-patient treatment. The control group consisted of 15 patients for every of the surveyed categories (group III - middle-aged and group IV – elderly respectively) matched with basic by age and gender. Results. We have shown that one of the factors that determines the change in hemodynamics in patients with essential hypertension is age, with the age patients experience the decrease in diastolic blood pressure with steadily increased systolic blood pressure, that should be considered in the prescription of antihypertensive treatment. With age, a gradual increase in systolic blood pressure is associated with the increased aortic stiffness, partially with the increase in collagen and the decrease in elastic fibrils and the formation of isolated systolic hypertension. Thus, it is proved that in the formation of isolated hypertension the growth of pulse blood pressure for more than 60 mm Hg is unfavorable in a development of cerebrovascular events. Pulse arterial blood pressure was stronger risk factor than systolic blood pressure and diastolic blood pressure or average arterial pressure in the elderly. Recently, taking into account age characteristics, all three indices were recognized as comparable predictors at the age of 50-59 years as the transitional period, and at the age of 60-79 years diastolic blood pressure adversely affecting the cardiovascular risk, increased pulse blood pressure prognostically above the level of systolic arterial pressure.


2017 ◽  
Vol XXII (130) ◽  
pp. 60-70
Author(s):  
Mariana Werneck Fonseca ◽  
Verônica Batista de Albuquerque ◽  
Gabriel T. N. Martins Ferreira ◽  
Marcelo Augusto de Araújo ◽  
Wagner Luis Ferreira ◽  
...  

This article investigates the electrocardiographic and blood pressure changes caused by different doses of morphine administered epidurally to bitches undergoing elective ovariohysterectomy. Twenty-four healthy bitches weighing 9.8 ± 4.1 kg were assigned to three experimental groups (in each group, n = 8): (i) group M0.1: 0.1 mg/kg morphine; (ii) group M0.15: 0.15 mg/kg morphine; and (iii) group M0.2: 0.2 mg/kg morphine. In all groups, levobupivacaine was added to achieve a total volume of 0.33 mL/kg. During the procedures, the following parameters were controlled: heart rate and rhythm, systolic blood pressure, rectal temperature and blood lactate. The data were analyzed by means of statistical methods of analysis of variance, such as Kruskal-Wallis, Fisher and Tukey tests. Epidural morphine did not cause significant electrocardiographic or blood pressure changes in the tested doses, which makes the use of this drug a viable alternative for epidural anesthesia.


1980 ◽  
Vol 58 (1) ◽  
pp. 115-117 ◽  
Author(s):  
D. B. Rowlands ◽  
T. J. Stallard ◽  
R. D. S. Watson ◽  
W. A. Littler

1. Ambulatory blood pressure recordings were made over a 48 h period on six hypertensive patients. The conditions of study were standardized, particularly with regard to physical activity, and during one period of each day the patients were randomly allocated to be active or inactive. 2. Results show that blood pressure was highest during physical activity and lowest during sleep. There was no significant difference between the arterial pressures measured during the same physical activities carried out at the same time each day. However, during the same time on consecutive days when activity was randomized, there was a significant difference between the pressure recordings during physical activity compared with those during inactivity. Heart rate changes showed a similar trend during the randomized period. 3. Physical activity and sleep have a profound effect on continuous arterial blood pressure recordings and these are independent of time alone. These observations should be taken into account when using this ambulatory system to assess hypotensive therapy.


1982 ◽  
Vol 62 (2) ◽  
pp. 137-141 ◽  
Author(s):  
L. Andrén ◽  
G. Lindstedt ◽  
M. Björkman ◽  
K. O. Borg ◽  
L. Hansson

1. Noise stimulation (95 dBA) for 20 min caused a significant increase in diastolic (12%, P < 0.001) and mean arterial pressure (7%, P < 0.001) in 15 healthy normotensive male subjects. 2. There was no significant change in systolic blood pressure or heart rate during exposure to noise. 3. Adrenaline, noradrenaline, prolactin, cortisol and growth hormone concentrations in venous plasma were not affected during noise stimulation.


2016 ◽  
Vol 3 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Manisha Pradhan ◽  
Brahma Dev Jha

Background: The ideal method to prevent hypotension due to intravenous propofol for induction of anesthesia is still debatable. The aim of the study was to compare the hemodynamic response of ephedrine and volume loading with ringer lactate in preventing the hypotension caused by propofol as inducing agent in patients scheduled for elective surgeries requiring general anesthesia with endotracheal intubation.Methods: This was prospective randomized study conducted in 40 patients of ASA physical status I, aged 20-50 years, scheduled for elective surgeries requiring general anesthesia with endotracheal intubation. Group I received intravenous ephedrine sulphate (70 mcg/kg) just before induction of anaesthesia, and patients assigned to Group II received preloading with Ringer's lactate (12 ml/kg) over the 10-15 minutes before the administration of propofol. The variables compared were heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure following induction of anesthesia till 10 minutes after intubation of trachea.Results: We found that there were increase in systolic blood pressure, diastolic blood pressure and mean arterial pressure after induction in both the groups but the difference between the groups was not significant. The increase in heart rate was found to be significantly higher in ephedrine group in comparison to volume loading group.Conclusion: Our study showed that both the methods used were equally effective in preventing hypotension induced by propofol in the adult ASA physical status I patients requiring general anesthesia with endotracheal intubation. However, the heart rate was significantly higher in patients receiving ephedrine in comparison to volume loading group.


1995 ◽  
Vol 88 (6) ◽  
pp. 651-655 ◽  
Author(s):  
Michel Ducher ◽  
Jean Pierre Fauvel ◽  
Marie Paule Gustin ◽  
Catherine Cerutti ◽  
Robert Najem ◽  
...  

1. A new method was developed to evaluate cardiac baroreflex sensitivity. The association of a high systolic blood pressure with a low heart rate or the converse is considered to be under the influence of cardiac baroreflex activity. This method is based on the determination of the statistical dependence between systolic blood pressure and heart rate values obtained non-invasively by a Finapres device. Our computerized analysis selects the associations with the highest statistical dependence. A ‘Z-coefficient’ quantifies the strength of the statistical dependence. The slope of the linear regression, computed on these selected associations, is used to estimate baroreflex sensitivity. 2. The present study was carried out in 11 healthy resting male subjects. The results obtained by the ‘Z-coefficient’ method were compared with those obtained by cross-spectrum analysis, which has already been validated in humans. Furthermore, the reproducibility of both methods was checked after 1 week. 3. The results obtained by the two methods were significantly correlated (r = 0.78 for the first and r = 0.76 for the second experiment, P < 0.01). When repeated after 1 week, the average results were not significantly different. Considering individual results, test—retest correlation coefficients were higher with the Z-analysis (r = 0.79, P < 0.01) than with the cross-spectrum analysis (r = 0.61, P < 0.05). 4. In conclusion, as the Z-method gives results similar to but more reproducible than the cross-spectrum method, it might be a powerful and reliable tool to assess baroreflex sensitivity in humans.


1976 ◽  
Vol 51 (s3) ◽  
pp. 357s-360s ◽  
Author(s):  
O. S. Randall ◽  
M. D. Esler ◽  
G. F. Bulloch ◽  
A. S. Maisel ◽  
C. N. Ellis ◽  
...  

1. The relationship between baroreflex sensitivity (BRS) and arterial compliance index (ACI) has been investigated (a) in paired subjects matched in one instance for systolic blood pressure with differing ages, and (b) in another instance matched for age with differing systolic blood pressures. 2. There was a significant negative correlation between BRS and age and between ACI and age in the twelve systolic blood pressure-matched subjects. 3. A significant negative correlation of systolic blood pressure with both BRS and ACI was observed in the fourteen age-matched subjects. 4. Both BRS and ACI appear to decrease with increasing age and systolic blood pressure. This decrease in BRS is probably due at least in part to the observed reduction in arterial distensibility.


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