Showing papers on "Ambulatory blood pressure published in 1991"
TL;DR: Findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.
Abstract: BACKGROUND To quantify the duration of postexercise hypotension at different exercise intensities, we studied six unmedicated, mildly hypertensive men matched with six normotensive controls. METHODS AND RESULTS Each subject wore a 24-hour ambulatory blood pressure monitor at the same time of day for 13 consecutive hours on 3 different days. On each of the 3 days, subjects either cycled for 30 minutes at 40% or 70% maximum VO2 or performed activities of daily living. There was no intensity effect on the postexercise reduction in blood pressure, so blood pressure data were combined for the different exercise intensities. Postexercise diastolic blood pressure and mean arterial pressure were lower by 8 +/- 1 (p less than 0.001) and 7 +/- 1 mm Hg (p less than 0.05), respectively, than the preexercise values for 12.7 hours in the hypertensive group. These variables were not different before and after exercise in the normotensive group. Systolic blood pressure was reduced by 5 +/- 1 mm Hg (p less than 0.05) for 8.7 hours after exercise in the hypertensive group. In contrast, systolic blood pressure was 5 +/- 1 mm Hg (p less than 0.001) higher for 12.7 hours after exercise in the normotensive group. When the blood pressure response on the exercise days was compared with that on the nonexercise day, systolic blood pressure (135 +/- 1 versus 145 +/- 1 mm Hg) and mean arterial pressure (100 +/- 1 versus 106 +/- 1 mm Hg) were lower (p less than 0.05) on the exercise days in the hypertensive but not in the normotensive group. We found a postexercise reduction in mean arterial pressure for 12.7 hours independent of the exercise intensity in the hypertensive group. Furthermore, mean arterial pressure was lower on exercise than on nonexercise days in the hypertensive but not in the normotensive group. CONCLUSION These findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.
344 citations
TL;DR: In order to determine reference values for ambulatory blood pressure, a sample of 815 healthy bank employees, aged 17-79 years, were investigated and office blood pressure was 4/2 mmHg lower than daytime ambulatory pressure.
Abstract: In order to determine reference values for ambulatory blood pressure, a sample of 815 healthy bank employees (399 men and 416 women), aged 17-79 years, were investigated. Ambulatory blood pressure was recorded over 24 h, taking measurements at 30-min intervals. Blood pressure was also measured by trained observers in the clinic. Ambulatory blood pressure in the 815 subjects averaged 118/72 mmHg over 24 h, 124/78 mmHg during the day (1000-2259 h) and 106/61 mmHg at night (0100-0659 h). Office blood pressure, measured by an observer, was 4/2 mmHg lower (p less than 0.0001) than daytime ambulatory pressure. The 95th centiles for the daytime ambulatory pressure in men were: 114/88 mmHg for the age group 17-29 years (n = 107); 143/91 mmHg from 30-39 years (n = 123); 150/98 mmHg from 40-49 years (n = 109); and 155/103 mmHg in 50-79 year old men (n = 60); for the corresponding age groups in women, the 95th centiles of the daytime pressure were: 131/83 mmHg (n = 174); 132/85 mmHg (n = 149); 150/94 mmHg (n = 55); and 177/97 mmHg (n = 38).
267 citations
TL;DR: Modulatory factors different from those controlling nycterohemeral changes in blood pressure influence the 24-hour variation in heart rate, which may reflect an endogenous circadian rhythm, amplified by the effect of sleep.
Abstract: To characterize the normal nycterohemeral blood pressure and heart rate profiles and to delineate the relative roles of sleep and circadian rhythmicity, we performed 24-hour ambulatory blood pressure monitoring with simultaneous polygraphic sleep recording in 31 healthy young men investigated in a standardized physical and social environment. Electroencephalographic sleep recordings were performed during 4 consecutive nights. Blood pressure and heart rate were measured every 10 minutes for 24 hours starting in the morning preceding the fourth night of recording. Sleep quality was not significantly altered by ambulatory blood pressure monitoring. A best-fit curve based on the periodogram method was used to quantify changes in blood pressure and heart rate over the 24-hour cycle. The typical blood pressure and heart rate patterns were bimodal with a morning acrophase (around 10:00 AM), a small afternoon nadir (around 3:00 PM), an evening acrophase (around 8:00 PM), and a profound nocturnal nadir (around 3:00 AM). The amplitude of the nycterohemeral variations was largest for heart rate, intermediate for diastolic blood pressure, and smallest for systolic blood pressure (respectively, 19.9%, 14.1%, and 10.9% of the 24-hour mean). Before awakening, a significant increase in blood pressure and heart rate was already present. Recumbency and sleep accounted for 65-75% of the nocturnal decline in blood pressure, but it explained only 50% of the nocturnal decline in heart rate. Thus, the combined effects of postural changes and the wake-sleep transition are the major factors responsible for the 24-hour rhythm in blood pressure. In contrast, the 24-hour rhythm of heart rate may reflect an endogenous circadian rhythm, amplified by the effect of sleep. We conclude that modulatory factors different from those controlling nycterohemeral changes in blood pressure influence the 24-hour variation in heart rate.
221 citations
TL;DR: Until the results of prospective studies on the relation between the ambulatory BP and the incidence of cardiovascular morbidity and mortality become available, the aforementioned intervals could serve as a temporary reference for clinical practice.
Abstract: To perform a meta-analysis of published reports in an attempt to determine the mean and range of normal ambulatory blood pressure (BP), 23 studies including a total of 3,476 normal subjects were reviewed. Most studies were compatible with a mean 24-hour BP in the range of 115 to 120/70 to 75 mm Hg, a mean daytime BP of 120 to 125/75 to 80 mm Hg, and a mean nighttime BP of 105 to 110/60 to 65 mm Hg. With weighting for the number of subjects included in the individual studies, the 24-hour BP averaged 118/72 mm Hg, the daytime BP 123/76 mm Hg, and the nighttime BP 106/64 mm Hg. The night/day pressure ratio averaged 0.87 for systolic and 0.83 for diastolic BP, with ranges across the individual studies from 0.79 to 0.92 and from 0.75 to 0.90, respectively. If the mean +/- 2 standard deviation interval in the various studies was considered normal, the range of normality was on average 97 to 139/57 to 87 mm Hg for the 24-hour BP, 101 to 146/61 to 91 mm Hg for the daytime BP, and 86 to 127/48 to 79 mm Hg for the nighttime BP. Until the results of prospective studies on the relation between the ambulatory BP and the incidence of cardiovascular morbidity and mortality become available, the aforementioned intervals, which summarize the experience of 23 investigators, could serve as a temporary reference for clinical practice.
207 citations
TL;DR: Findings indicate that, in some subjects with borderline or mild hypertension, a physical training programme is sufficient to bring the blood pressure within normal limits.
195 citations
TL;DR: Findings obtained in a natural setting lend further support to the significance of cynical hostility for cardiovascular reactivity and suggest the need for further research on the role of conflicting attitudes in the pathophysiology of cardiovascular diseases.
Abstract: Ambulatory blood pressure and heart rate responses were obtained in 33 male paramedics during a &hour work shift to examine the effects of episodes of occupational stress on cardiovascular reactivity and subjective reports of stress. The aim of this study was to determine how individual differences in cynical hostility and defensiveness interacted with situational demands to affect cardiovascular responses in a natural setting. Defensiveness was found to interact significantly with cynical hostility in predicting subjects' heart rate responses in different work contexts. Specifically, in a hospital setting involving interpersonal conflict, subjects who were high in both defensiveness and hostility showed heart rate responses approximately do bpm higher than subjects who were high in hostility but low in defensiveness. I The same pattern of relationships was obtained for diastolic blood pressure. High and low hostile subjects were also found to differ from each other in their daily mean levels of ambulatory blood pressure during awake and sleep periods. These findings obtained in a natural setting lend further support to the significance of cynical hostility for cardiovascular reactivity. The results for defensiveness suggest the need for further research on the role of conflicting attitudes in the pathophysiology of cardiovascular diseases.
172 citations
Journal Article•
TL;DR: In patients with nocturnal reduction in average daytime systolic and diastolic blood pressure, left ventricular mass seems to be greater in non-dippers than in dippers among women, but not in men.
Abstract: Clinical studies with non-invasive ambulatory blood pressure monitoring have shown that some cardiovascular complications of essential hypertension (left ventricular hypertrophy, stroke) tend to be more frequent in patients whose 24-h blood pressure profile is flattened (non-dippers) and, consequently, suffer a longer duration of exposure to high blood pressure levels over the 24 h. The distribution of patients between dippers and non-dippers is conditioned by the limits of the blood pressure changes from day to night that are arbitrarily chosen to define these two groups, and by the time intervals defining daytime and night-time hours. Sleep does not seem to be disturbed by non-invasive monitoring to such an extent that the day-night blood pressure difference is affected. If daytime is defined as 0600-2200 h and night-time as 2200-0600 h, and those hypertensive patients with a nocturnal reduction in average daytime systolic and diastolic blood pressure of less than 10% are classed as non-dippers, the prevalence of non-dippers in essential hypertension appears to be about 35%. In these patients, left ventricular mass seems to be greater in non-dippers than in dippers among women, but not in men. The clinical significance of the dippers/non-dippers classification in the stratification of hypertensive patients of different levels of risk of cardiovascular complications needs further investigation.
165 citations
TL;DR: Diurnal blood pressure variation was studied by ambulatory 24-hour monitoring in patients with advanced chronic renal failure, on chronic hemodialysis, after renal transplantation and in matched control groups without renal disease.
Abstract: Diurnal blood pressure variation was studied by ambulatory 24-hour monitoring in patients with advanced chronic renal failure (n = 20), on chronic hemodialysis (n = 20), after renal transplantation (n = 21) and in matched control groups without renal disease. Nocturnal blood pressure reductions were significantly blunted in all patient groups as compared with the respective control groups. In almost none of the 61 controls did the mean values during nighttime (8 p.m.-8 a.m.) exceed the mean day time values (8 a.m.-8 p.m.). In 10 of the 61 renal patients blood pressure was higher during the night. In patients with chronic renal disease nocturnal blood pressure elevation may be diagnosed by ambulatory 24-hour monitoring. This may require adaptation of antihypertensive treatment.
151 citations
TL;DR: The standard deviation of the mean difference (s.d.d.) between blood pressures obtained in each recording was taken as the reciprocal of blood pressure reproducibility, which was highest for office blood pressure and for single blood pressure readings taken from 24-h non-invasive recordings.
Abstract: Ambulatory blood pressure has been shown to be more reproducible than office blood pressure and thus to be more suited for studying the efficacy of antihypertensive drugs. In 34 untreated essential hypertensive subjects, we measured office and 24-h non-invasive or intra-arterial blood pressure twice
149 citations
Journal Article•
TL;DR: In this paper, a meta-analysis suggested that hypertension may be suspected if the 24-hour blood pressure exceeds 129/87 mmHg, or if the daytime or night-time pressures are higher than 146/91 mm Hg or 127/79 mmHG, respectively, and that placebo effects are not observed when blood pressure is measured with ambulatory recorders.
Abstract: Monitoring ambulatory blood pressure, instead of taking pressure readings in hospital, avoids the so-called white-coat effect and allows more readings to be obtained over a longer period of time. It improves the accuracy of the blood pressure estimate and increases the statistical power of therapeutic trials for hypertension. Subjects with white-coat or office hypertension can be detected by ambulatory blood pressure monitoring and excluded from clinical trials. In 23 studies, including a total of 3304 normotensive subjects, the 24-h ambulatory blood pressure averaged 118/72 mmHg; the daytime and night-time pressures were 123/76 mmHg and 106/64 mmHg, respectively. If the mean plus two standard deviation (s.d.) interval is considered the upper limit of normal, the meta-analysis suggested that hypertension may be suspected if the 24-h pressure exceeds 129/87 mmHg, or if the daytime or night-time pressures are higher than 146/91 mmHg or 127/79 mmHg, respectively. On balance, most studies suggest that placebo effects on blood pressure are not observed when blood pressure is measured with ambulatory recorders. If confirmed, this observation indicates that it is possible to simplify the design of trials in the field of hypertension. Ambulatory blood pressure readings should be obtained with properly validated monitors. If the recordings are of sufficient quality, editing does not increase the precision of the subsequent statistical analyses. The statistical analyses should account for diurnal rhythms, and subject and treatment effects.
129 citations
TL;DR: A measure of job strain derived from the occupational classification is useful in predicting variations in diastolic blood pressure levels during sleep and work for men with borderline hypertension.
Abstract: Occupational characteristics were used to study the role of job stress in the pathogenesis of hypertension. Ambulatory 24-h recordings of blood pressure were made for 161 men with borderline hypertension. From the occupational classification system scores for psychological demands, control, support, physical demands, and occupational hazards were obtained. The results indicated that the ratio between psychological demands and control (strain) was significantly associated with diastolic (but not systolic) blood pressure at night and during work. The association between job strain and diastolic blood pressure at night and during work was greatly strengthened when the subjects with occupations classified as physically demanding were excluded from the analysis. The conclusion was reached that a measure of job strain derived from the occupational classification is useful in predicting variations in diastolic blood pressure levels during sleep and work for men with borderline hypertension.
Journal Article•
TL;DR: While the evidence shows a closer relationship between ambulatory compared with clinic blood pressure measurements and left ventricular mass or other measures of hypertensive disease, it is not clear which measures of ambulatory blood pressure are the most important.
Abstract: Certain forms of preclinical cardiovascular disease are critical to the transition between hypertension and the development of cardiovascular morbid events. The level of the echocardiographic left ventricular mass is a stronger predictor of death or non-fatal events than arterial pressure or any other risk factor except advancing age. While the evidence shows a closer relationship between ambulatory compared with clinic blood pressure measurements and left ventricular mass or other measures of hypertensive disease, it is not clear which measures of ambulatory blood pressure are the most important. Present evidence weakly favors systolic over diastolic ambulatory pressure and daytime over night-time pressures. Further studies of large, well defined populations with standardized components of ambulatory blood pressure and well validated measures of hypertensive target organ damage are needed.
TL;DR: The variety of BP measurements noted at different activity levels indicate that a child's activity should be considered during data analysis and should prove helpful in diagnosis and management of hypertension in children.
TL;DR: The frequent occurrence of white coat phenomenon in hypertensive patients receiving drug therapy suggests that office BP readings may not always represent usual ABP in patients receiving chronic antihypertensive therapy.
Journal Article•
TL;DR: It was documented the existence of white coat hypertension in children and showed that white coat hypertensive children were significantly different from normotensive and hypertensiveChildren on most comparisons of 24-hour ABPM data.
Abstract: BACKGROUND: Research with ambulatory blood pressure monitoring (ABPM) clearly demonstrates the importance of identifying "white coat" hypertension before making the diagnosis of hypertension. While the existence of white coat hypertension has been documented in adults, it is unknown whether this phenomenon is present during childhood. Therefore, the purposes of this study were to determine whether white coat hypertension exists in children with a positive family history of essential hypertension; and if it exists, to compare 24-hour ambulatory blood pressure patterns among normotensive, white coat hypertensive, and hypertensive children. METHODS: One hundred fifty-nine children (aged 5 to 15 years) participated in the study. Based on office systolic and diastolic measurements and 24-hour ABPM, subjects were placed into one of three groups: normotensive, white coat hypertensive, and hypertensive. RESULTS: Forty-four percent of 34 subjects with systolic blood pressures greater than or equal to 95th percentile were reclassified as white coat hypertensive; 56% remained hypertensive. Group comparisons of 24-hour ABPM patterns showed significant differences between groups. Also, the ABPM patterns of white coat hypertensive patients were significantly different from those of normotensive patients. CONCLUSIONS: This study documented the existence of white coat hypertension in children and showed that white coat hypertensive children were significantly different from normotensive and hypertensive children on most comparisons of 24-hour ABPM data. Also, when age and sex were controlled, heavier children had a more significant chance of having elevated systolic blood pressure than normal-weight children, regardless of their race, height, or body mass index.
Journal Article•
TL;DR: In this paper, a population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated, and the ambulatory blood pressure was recorded over 24 hours, taking measurements at 20min intervals from 8 am to 10 pm, and at 45 min intervals from 10 pm to 8 am.
Abstract: Summary: In order to determine reference values for the ambulatory blood pressure, a population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated. The ambulatory blood pressure was recorded over 24 h, taking measurements at 20 min intervals from 8 am to 10 pm, and at 45 min intervals from 10 pm to 8 am. Blood pressure was also measured by trained observers on each of two separate home visits (5 readings per visit). The ambulatory blood pressure in the 328 subjects averaged 118171 mmHg over 24 h, 124176 mmHg during the day (10 am-8 pm), and 108162 mmHg at night (0 am-6 am). Blood pressure measured by an observer at the occasion of the second home visit was 415 mmHg lower (P<0.001) than the daytime ambulatory blood pressure. The 95th centiles for the daytime ambulatory pressures were 144195 mmHg in 85 men below age 50; 154190 mmHg in 74 men aged 250 years; 132185 mmHg in 96 women below age 50; and 151191 mmHg in 73 women aged 250 years. The 95th centiles for the nighttime pressures in these four sex-age groups were 124179, 140183, 121170, and 132172 mmHg, respectively.
TL;DR: The dose response relationship of oral nifedipine is influenced by the circadian organization of the cardiovascular system as well as by the galenic drug formulation.
Abstract: Circadian phase dependency in pharmacokinetics and hemodynamic effects on blood pressure and heart rate of different galenic formulations of nifedipine (immediate-release, sustained-release, and i.v. solution) were studied in healthy subjects or in hypertensive patients. Pharmacokinetics of immediate-release but not sustained-release and i.v. nifedipine were dependent on time of day: immediate-release nifedipine had higher Cmax (peak concentration) and shorter tmax (time-to-peak concentration) after morning than evening application, and bioavailability in the evening was reduced by about 40%. Circadian rhythm in estimated hepatic blood flow as determined by indocyanine green kinetics may contribute to these chronokinetics. A circadian time dependency was also found in nifedipine-induced effects on blood pressure and heart rate as monitored by 24-h ambulatory blood pressure measurements. In conclusion, the dose response relationship of oral nifedipine is influenced by the circadian organization of the cardiovascular system as well as by the galenic drug formulation.
TL;DR: It is demonstrated that ambulatory BP determinants but not office BP parameters are well correlated with LV hypertrophy in essential hypertension and nonhemodynamic factors are important determinants of LV mass as well.
Abstract: In a group of 36 untreated patients with mild to moderate essential hypertension (office systolic and diastolic blood pressures (BPs) 160 ± 3.4 and 102 ± 1.5 mm Hg, respectively), a 24-hour ambulatory BP monitoring and determination of left ventricular (LV) mass index according to the formula of Devereux were performed. After an overnight fast, blood samples were taken for the determination of serum aldosterone, plasma renin activity and serum parathyroid hormone. Urinary catecholamines were sampled for 24 hours. LV mass index (143.7 ± 8 g/m2) did not correlate significantly either with office systolic or diastolic BP. The correlation of LV mass index with mean 24-hour systolic BP (145 ± 3 mm Hg) was statistically significant: r = 0.395, p = 0.026. However, the best correlation was obtained with mean 24-hour diastolic BP (90 ± 3 mm Hg) with r = 0.500 (p = 0.004). Urinary catecholamines were not correlated with LV mass index. LV mass index correlated significantly with plasma renin activity (r = 0.346, p = 0.050), and aldosterone (r = 0.559, p = 0.001). There was a very significant correlation between LV mass index and parathyroid hormone (r = 0.719, p = 0.00001) even after adjustment for mean 24-hour systolic and diastolic BPs. These results clearly demonstrate that ambulatory BP determinants but not office BP parameters are well correlated with LV hypertrophy in essential hypertension. Nonhemodynamic factors are important determinants of LV mass as well. Besides the renin-angiotensin-aldosterone system, parathyroid hormone appears to play an important role in cardiac hypertrophy.
Journal Article•
TL;DR: The accuracy of the TM-2420 ambulatory blood pressure monitor has been assessed by the indirect method according to the recommendations of the Association for the Advancement of Medical Instrumentation (AAMI), and the device found to be acceptable.
Abstract: The accuracy of the TM-2420 ambulatory blood pressure monitor (AD these differences were not significant (NS). The monitor was also assessed against direct intra-brachial artery pressure in 12 subjects (36 readings). The mean difference between the monitor and simultaneous individual intra-arterial reading was -9.5 mmHg for SBP (P less than 0.001) and 3.7 mmHg for DBP (P less than 0.001). The SDD's between methods were 12 mmHg for SBP and 5.0 mmHg for DBP. Use of the monitor in general clinical practice in 100 patients was also assessed. The rate of errors was low (6.8%), and the device found to be acceptable.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The prevalence of postural change in blood pressure and its association with age and systolic blood pressure were examined in data from 8,574 White nondiabetic persons aged 25-74 who participated in the second National Health and Nutrition Examination Survey (1976-1980) as discussed by the authors.
Abstract: The prevalence of postural change in blood pressure and its association with age and systolic blood pressure were examined in data from 8,574 White nondiabetic persons aged 25-74 who participated in the second National Health and Nutrition Examination Survey (1976-1980). Postural change in blood pressure was defined as a drop of 20 mm Hg or more on change from supine to seated position. In subjects on no antihypertensive medications (n = 7,316), the prevalence of postural change in blood pressure increased with older age and with higher blood pressure levels, regardless of age. However, systolic blood pressure levels also increased with age. In logistic regression models, level of supine systolic blood pressure was strongly related to postural change in blood pressure (Relative odds (RO) = 1.59, 95% confidence interval (CI) = 1.49, 1.70 for a 10 mm Hg increase in systolic blood pressure) whereas age was not related to postural change in blood pressure (RO for age = 1.07, Cl = .89, 1.19 for a 10-year increase in age). Results were similar for those medicated for hypertension. All results were unchanged by addition of health status indicators, including reports of hospitalization and number of medical conditions, to the model. These data suggest that the age-related increase in the prevalence of postural hypotension previously reported may be partially explained by age-associated increases in systolic blood pressure.
Journal Article•
TL;DR: A population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated, and reference values for the ambulatory blood pressure were determined.
Abstract: In order to determine reference values for the ambulatory blood pressure, a population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated. The ambulatory blood pressure was recorded over 24 h, taking measurements at 20 min intervals from 8 am to 10 pm, and at 45 min intervals from 10 pm to 8 am. Blood pressure was also measured by trained observers on each of two separate home visits (5 readings per visit). The ambulatory blood pressure in the 328 subjects averaged 118/71 mmHg over 24 h, 124/76 mmHg during the day (10 am-8 pm), and 108/62 mmHg at night (0 am-6 am). Blood pressure measured by an observer at the occasion of the second home visit was 4/5 mmHg lower (P less than 0.001) than the daytime ambulatory blood pressure. The 95th centiles for the daytime ambulatory pressures were 144/95 mmHg in 85 men below age 50; 154/90 mmHg in 74 men aged greater than or equal to 50 years; 132/85 mmHg in 96 women below age 50; and 151/91 mmHg in 73 women aged greater than or equal to 50 years. The 95th centiles for the nighttime pressures in these four sex-age groups were 124/79, 140/83, 121/70, and 132/72 mmHg, respectively.
TL;DR: The diurnal BP rhythm is largely dependent on activity and sleep rather than on clock time, which has been demonstrated by the BP characteristics after shifted sleeping and working phases, during transition from sleep to wakefulness, and by the influence of sleep and activities on the 24-h BP curve during normal daily routines.
Abstract: Diurnal blood pressure (BP) fluctuations are superimposed by a 24-h rhythm with usually lower levels during the night and higher levels during the day. In contrast to other rhythmic bioparameters, the diurnal BP rhythm is largely dependent on activity and sleep rather than on clock time. This has been demonstrated by the BP characteristics after shifted sleeping and working phases, during transition from sleep to wakefulness, and by the influence of sleep and activities on the 24-h BP curve during normal daily routines. Whereas the circadian rhythm of BP is predominantly governed by external time triggers, endogenous rhythmicity can only be detected by time microscopic analysis or in conditions where effects of external time triggers are almost excluded.
TL;DR: In 27 essential hypertensive outpatients, blood pressure was measured in the doctor's office and by 24-h ambulatory blood pressure monitoring after a 3-week wash-out period from antihypertensive treatment (Control) and following 4 weeks of placebo administration.
Abstract: Twenty-four-hour mean ambulatory blood pressure has been shown to be devoid of a placebo effect. However, whether this is the case for different periods within the 24 h has not been established. In 27 essential hypertensive outpatients, blood pressure was measured in the doctor's office and by 24-h ambulatory blood pressure monitoring after a 3-week wash-out period from antihypertensive treatment (Control) and following 4 weeks of placebo administration. Office systolic and diastolic blood pressures were reduced by placebo (-9.6 +/- 2.6 and -3.1 +/- 1.7 mmHg, P less than 0.01, respectively), whereas 24-h mean blood pressure values did not show any significant change. This was not the case for all 24-h subperiods, however, because during the initial 8h, systolic and diastolic blood pressures were slightly (-4.1 +/- 9.2 and -2.5 +/- 6.4 mmHg) but significantly (P less than 0.05) lower during placebo than during control. Similar findings were obtained in 14 additional essential hypertensive patients in whom neither placebo nor any other treatment was employed between the two office and 24-h blood pressure measurements. Thus, placebo treatment is associated with a blood pressure reduction in the initial portion of the ambulatory blood pressure profile, probably because of an attenuation of an initial transient alerting response to the procedure. Although so small as to leave the 24-h blood pressure mean unaffected, this may lead to some overestimation of the antihypertensive effect of treatment during an appreciable portion of the circadian blood pressure tracing.
TL;DR: The results suggest that in the hospitalized normotensive NIDDM subjects, there are normal and reversed circadian MBP rhythms and that the reversal of normal MBP rhythm may be related to the degree of postural hypotension and/or nephropathy.
Abstract: Objective To investigate the relationship between circadian rhythm of mean blood pressure (MBP) and microvascular complications in non-insulin-dependent diabetes mellitus (NIDDM) subjects. Research Design and Methods Seventy-six normotensive NIDDM subjects without azotemia were studied under ordinary hospital conditions with a noninvasive ambulatory blood pressure monitoring device. Time series data were analyzed by the cosinor method. Results Fifty-four subjects had a circadian MBP rhythm similar to that of 34 age-matched nondiabetic control subjects, with a peak value in the afternoon (group 1). In contrast, 22 had a reversed circadian MBP rhythm, with a peak value during the night (group 2). Obvious complications were found in 65% of group 1 and in all of group 2. The prevalence of retinopathy and somatic neuropathy and the degree of retinopathy were similar in the two groups. The prevalence and degree of autonomic neuropathy (postural hypotension and reduced beat-to-beat heart-rate variation) and nephropathy were greater in group 2 than group 1. Linear discriminant analysis revealed a correlation between the reversed circadian MBP rhythm and postural hypotension ( F = 32.2, P F = 5.1, P F = 0.17, NS). Conclusions These results suggest that in the hospitalized normotensive NIDDM subjects, there are normal and reversed circadian MBP rhythms and that the reversal of normal circadian MBP rhythm may be related to the degree of postural hypotension and/or nephropathy.
Journal Article•
TL;DR: Recent data presented here demonstrate that blood pressure load, expressed as a percentage value in mild hypertensives or as an integrated area under the curve in more moderate and severe hypertensive, is a better determinant of cardiac or vascular abnormalities than either casual or mean ambulatory blood pressure.
Abstract: The ambulatory blood pressure load has been defined as the elevated systolic and/or diastolic pressures over a 24-h period. This parameter, in a sense, represents the chronic pressure overload that induces myocardial and vascular damage associated with the hypertensive disease process. In recent years, blood pressure load has been arbitrarily defined as the percentage of blood pressures greater than 140/90 mmHg while awake and greater than 120/80 mmHg during sleeping hours or the integrated area under the blood pressure curve above the same values. Recent data presented here demonstrate that blood pressure load, expressed as a percentage value in mild hypertensives or as an integrated area under the curve in more moderate and severe hypertensives, is a better determinant of cardiac or vascular abnormalities than either casual or mean ambulatory blood pressure.
TL;DR: The results of this study support research that has demonstrated a stronger relation between Na+ handling and casual blood pressure in black subjects and extend these findings to blood pressure while the subject is both awake and asleep.
Abstract: The influence of Na+ excretion and race on casual blood pressure and ambulatory blood pressure patterns was examined in a biracial sample of healthy, normotensive children and adolescents (10-18 years; n = 140). The slopes relating 24-hour urinary Na+ excretion to systolic blood pressure were different for both black and white subjects for casual blood pressure (p less than 0.001) and blood pressure during sleep (p less than 0.03). For casual blood pressure, the slope was significant for black subjects (beta = 0.17; p less than 0.001) but not for white subjects. For blood pressure during sleep, the slope was again significant for black subjects (beta = 0.08; p less than 0.01) but not for white subjects. Na+ excretion was also related to awake levels of systolic blood pressure for black subjects (beta = 0.08, r = 0.36; p less than 0.01), although the slopes for both black and white subjects were not significantly different. Further analyses indicated the results were not due to racial differences in 24-hour urinary K+ excretion. However, plasma renin activity was marginally related to Na+ excretion in white subjects (r = 0.22; p less than 0.06) but not black subjects, a finding that is consistent with previous studies. Na+ excretion was not associated with diastolic blood pressure or heart rate in either group under any condition. The results of this study support research that has demonstrated a stronger relation between Na+ handling and casual blood pressure in black subjects and extend these findings to blood pressure while the subject is both awake and asleep.
TL;DR: An acceptable level of accuracy and performance of the sixth generation of the TM-2420 for use in clinical practice and research is demonstrated.
Journal Article•
TL;DR: The PAMELA Study has been planned to obtain an epidemiological evaluation of 24-h ambulatory blood pressure values, and its design is described here.
Abstract: Although ambulatory blood pressure monitoring is gaining in popularity, it still has important limitations in clinical use, particularly for the definition and diagnosis of hypertension. Various attempts have been made to calculate 'normal' or 'reference' values for ambulatory blood pressure, mostly by 24-h non-invasive monitoring in groups of 'normal' subjects. The most appropriate approach, however, is to compare 24-h ambulatory blood pressure values and casual or clinic blood pressure values in a random sample of a suitably large population. The PAMELA Study has been planned to obtain an epidemiological evaluation of 24-h ambulatory blood pressure values, and its design is described here. In the city of Monza, 2400 subjects aged between 25 and 64 years have been randomly selected according to World Health Organization Monitoring Cardiovascular Diseases (WHO-MONICA) project criteria within sex and age strata. In these subjects, clinic blood pressure, random-zero blood pressure, ambulatory blood pressure (24-h monitoring with SpaceLabs 90207; Redmond, Washington, USA), home blood pressure, electrocardiographic and echocardiographic indices, cardiovascular risk factors and psychological variables are being measured.
Journal Article•
TL;DR: The SpaceLabs 90202 fulfills the criteria of the AAMI standard (5 +/- 8 mmHg) and a B grading for both systolic and diastolic pressure is achieved with the BHS criteria.
Abstract: Summary: The SpaceLabs 90202, a non-invasive ambulatory blood pressure recorder for the measurement of 24 hr blood pressure, was assessed according to the standard of the Association for the Advancement of Medical Instrumentation (AAMI) and the grading criteria of the British Hypertension Society (BHS) protocol were applied to the results. Two observers measured BP simultaneously in the same arm with the SpaceLabs 90202 and a standard mercury sphygmomanometer at 4 mmHg deflation steps in 85 subjects [age range 22-79 years, BP range 96-212mmHg (systolic) and 52-134mmHg (diastolic)l. The mean difference ( f SD) between the SpaceLabs 90202 and the mercury sphygmomanometer was - 2 f 5 mmHg (systolic) and - 2 f 5 mmHg (diastolic). The mean difference (f SD) between observers was 1 f 3 (systolic) and - 2 f 3 (diastolic). The SpaceLabs 90202 fulfills the criteria of the AAMI standard (5 f 8 mmHg) and a B grading for both systolic and diastolic pressure is achieved with the BHS criteria.