Improvement in left ventricular function after rapid weight loss in obesity.

The effect of rapid weight reduction on left ventricular function and blood pressure was studied in 34 obese subjects, who all weighed more than 30% above their ideal body weight. Subjects with co-existing hypertension (N = 15) and proven coronary artery disease (N = 9) were included to assess contributions from these factors. Blood pressure (BP) was measured both indirectly and by direct ambulatory intra-arterial methods. Radionuclide ventriculography was performed at rest and at exercise, before and after dieting, which was supervised in hospital (daily intake 330 kCal day-1 for 4 weeks). Dieting induced a weight loss of (mean +/- SD) 9.6 +/- 3.5 kg (P less than 0.0001) in the whole group. The mean daytime intra-arterial blood pressure fell from 157 +/- 23/90 +/- 15 to 144 +/- 21/85 +/- 13 mmHg (P less than 0.0001). The fall in ambulatory intra-arterial diastolic blood pressure did not reach significance in the normotensive and ischaemic groups. The mean resting left ventricular ejection fraction (LVEF) in the whole group showed a significant reduction after weight loss from 61 +/- 10% to 56 +/- 6% (P less than 0.005). Although the individual groups showed a fall in LVEF, the effect was most marked in the hypertensive group, from 65 +/- 9% to 57 +/- 5% (P less than 0.002). Before dieting none of the groups achieved a 'normal' 5% rise in LVEF above basal in response to exercise, the hypertensive and the ischaemic groups both showing non-significant falls. This phenomenon was, however, reversed after weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hypertension in obese children: fasting serum insulin levels are closely correlated with blood pressure

The relationship between blood pressure and anthropometric or metabolic factors was studied in 324 obese children aged 9.5 +/- 1.8 years (mean +/- standard deviation). Obese children had a significantly higher blood pressure than non-obese children (systolic blood pressure: 121 +/- 14 mmHg in obese children vs 112 +/- 11 mmHg in non-obese children, P less than 0.001; diastolic blood pressure: 72 +/- 9 mmHg in obese children vs 66 +/- 7 mmHg in non-obese children, P less than 0.001). When the obese children were divided into hypertensive and normotensive groups, there was a significant difference in fasting serum insulin levels between the two groups (19.3 +/- 9.3 microU/ml in the hypertensive group vs 13.0 +/- 6.1 microU/ml in the normotensive group), and a close correlation between fasting serum insulin levels and systolic blood pressure was demonstrated (r = 0.63, P less than 0.001). However, there was no significant correlation between blood pressure and the degree of obesity itself or the waist-to-hip ratio in the obese children. There was no significant correlation between blood pressure and fasting plasma glucose, serum total cholesterol, or triglycerides levels in the obese children. Moreover, the correlation between fasting insulin levels and blood pressure was shown to be independent of the degree of obesity or waist-to-hip ratio and age by multiple regression analysis. These results indicate that hyperinsulinemia itself may play an important role in the pathogenesis of hypertension in obese children.     

Decreased exercise capacity in mild essential hypertension: non-invasive indicators of limiting factors.

Available data suggest that exercise capacity is limited in hypertension. The mechanism of this reduced maximal exercise capacity has not been fully elucidated. In this study 22 patients with mild essential hypertension (162 +/- 22 mmHg systolic and 95 +/- 8 mmHg diastolic) and 36 normotensive control subjects (128 +/- 13 mmHg systolic and 80 +/- 7 mmHg diastolic) (P less than 0.01) performed an ergometer test till exhaustion. Body mass index in the two groups did not differ. The maximal oxygen consumption VO2 was lower in the hypertensive group (18 +/- 7 versus 23 +/- 8 ml/kg/min; P less than 0.02) as was the maximal workload (141 +/- 52 vs. 185 +/- 70 Watt; P less than 0.01). Rate pressure product rose only 2.7 fold in hypertensive patients versus 3.5 fold in the control group (P less than 0.001). In hypertensive patients maximal workload decreased with increasing resting systolic blood pressure (P less than 0.05) while in the normotensive subjects maximal workload rose with increasing resting systolic blood pressure (P less than 0.05). In conclusion both high and low blood pressure was associated with a decreased maximal voluntary exercise capacity. Even mild hypertension was accompanied by lower maximal exercise capacity. Hypertensive patients also had a lower maximal VO2 and lower maximal rate pressure product than did normotensive subjects.     

Prevalence of sustained hypertension and obesity in urban and rural school going children in Ludhiana

BACKGROUND: Increasing trend of hypertension is a worldwide phenomenon. The data on sustained hypertension in school going children is scanty in India. The present study was conducted to evaluate the prevalence of sustained hypertension and obesity in apparently healthy school children in rural and urban areas of Ludhiana using standard criteria. METHODS AND RESULTS: A total of 2467 apparently healthy adolescent school children aged between 11-17 years from urban area and 859 students from rural area were taken as subjects. Out of total 3326 students, 189 were found to have sustained hypertension; in urban areas prevalence of sustained hypertension was 6.69% (n=165) and in rural area it was 2.56% (n=24). Males outnumbered females in both rural and urban areas. The mean systolic and diastolic blood pressure of hypertensive population in both urban and rural population was significantly higher than systolic and diastolic blood pressure in their normotensive counterparts (urban normotensive systolic blood pressure:115.48+/-22.74 mmHg, urban hypertensive systolic blood pressure: 137.59+/-11.91 mmHg, rural normotensive systolic blood pressure: 106.31+/-19.86 mmHg, rural hypertensive systolic blood pressure: 131.63+/-10.13 mmHg, urban normotensive diastolic blood pressure: 74.18+/-17.41 mmHg, urban hypertensive diastolic blood pressure: 84.58+/-8.14 mmHg, rural normotensive diastolic blood pressure: 68.84+/-16.96 mmHg, rural hypertensive diastolic blood pressure: 79.15+/-7.41 mmHg). Overweight populationwas significantly higher in urban area. There were 287 (11.63%) overweight students and 58 (2.35%) were obese. In rural population overweight and obese students were 44 (4.7%) and 34 (3.63%) respectively. There was significant increase in prevalence of hypertension in both rural and urban population with increased body mass index in urban students; those with normal body mass index had prevalence of hypertension of 4.52% (n=96), in overweight it was 15.33% (n=44) and in obese it was 43.10% (n=25). In rural area, the overweight students showed prevalence of sustained hypertension in 6.82% (n=3) and in obese group it was 61.76% (n=21). None of the student with normal body mass index in rural area was found to be hypertensive. The mean body mass index of hypertensive population in both rural and urban areas was significantly higher than respective normotensive population (mean body mass index in urban normotensive group: 20.34+/-3.72 kg/m2, hypertensive group: 24.91+/-4.92 kg/m2; mean body mass index in rural normotensive group: 18.41+/-3.41 kg/m2, hypertensive group: 21.37+/-3.71 kg/m2, p<0.01). CONCLUSIONS: Prevalence of sustained hypertension is on the rise in urban area even in younger age groups. Blood pressure is frequently elevated in obese children as compared to lean subjects. This is possibly related to their sedentary lifestyle, altered eating habits, increased fat content of diet and decreased physical activities.     

Relationship between ambulatory blood pressure monitoring and response of blood pressure in male hypertensive adolescents to exercise

BACKGROUND: High blood pressure in the young has been related to the development of hypertension in adults; hence the importance of identifying adolescents with the risk of developing it.OBJECTIVE: To investigate the relationship between 24 h ambulatory blood pressure monitoring and the response of blood pressure in adolescents to exercise. DESIGN: A prospective and cross-sectional study. METHODS: We classified 101 men aged 13-18 years as obese hypertensive, lean hypertensive, obese normotensive, and lean normotensive. Mean blood pressure and variability were measured with ambulatory blood pressure monitoring, and expressed as 24 h, awake, and sleeping periods. Treadmill tests were also performed. RESULTS: Hypertensives and obese normotensives had higher ambulatory blood pressure monitoring values (P< 0.0001). Systolic blood pressure during sleep in obese subjects was significantly higher than that in lean usbjects (119.9 +/- 9 versus 113.6 +/- 8 mmHg, P < 0.001, obese hypertensives versus lean hypertensives; and 113.6 +/- 2 versus 103.0 +/- 2 mmHg, P < 0.002, obese normotensives versus lean normotensives) and nocturnal drop of systolic blood pressure was lower in obese subjects. We found a significant correlation between systolic blood pressure during ambulatory blood pressure monitoring and systolic blood pressure during moderate and maximal exercise for all periods (P < 0.0001). Blood pressure variability during awake period was higher in subjects with maximum exercise systolic blood pressure >/= 200 mmHg (7.4 +/- 2 versus 6.4 +/- 2%, P < 0.01).CONCLUSION: Systolic blood pressure measured by ambulatory blood pressure monitoring is related to response of systolic blood pressure to exercise and ambulatory blood pressure monitoring can identify groups of subjects at greater than normal risk through their higher blood pressure during sleep. Greater than normal blood pressure variability in adolescents is an indicator of the risk of reaching abnormal exercise values of systolic blood pressure. Higher casual blood pressure than ambulatory blood pressure monitoring values for adolescents should be considered abnormal.     

Intra-arterial pressure alterations during tail-cuff blood pressure measurements in normotensive and hypertensive rats

The heating and restraint inherent to tail-cuff measurement of systolic blood pressure (SBP) in rats may alter SBP and introduce a 'biological' error in its estimation by this technique. This problem was examined in unanesthetized normotensive and hypertensive rats fitted with an arterial catheter. All SBP values recorded in unrestrained rats during a 2 h period were averaged by computer and compared with intra-arterial SBP measurements observed while the rat was being subjected to the tail-cuff procedure. With the latter procedure, SBP was 16 +/- 2 mmHg lower in normotensive rats (P less than 0.001) and 7 +/- 3 mmHg higher in hypertensive rats (P less than 0.05) than when the rats were unrestrained. The effects of heat and restraint, both separately and in combination, on SBP were evaluated during four additional 30-min monitoring periods. In both groups of rats, restraint failed to alter SBP and heat lowered it slightly. The two stimuli, combined, lowered SBP in normotensive rats, but raised it by 12 +/- 2 mmHg in hypertensive rats (P less than 0.01). Thus, tail-cuff SBP measurements represent under- and overestimates in normotensive and hypertensive rats, respectively, since the two groups respond to the procedure in opposite manners.     

Weight reduction decreases atrial natriuretic factor and blood pressure in obese patients

The relationship between atrial natriuretic factor (ANF), the renin-aldosterone axis, and blood pressure reduction with weight loss was investigated in 18 obese subjects (five hypertensive and 13 normotensive) placed on a 12-week, low-sodium (40 mmol), weight-reducing diet. ANF was significantly higher (P less than .02) in the obese hypertensive group compared with the obese normotensive group throughout the study. There was a dramatic fall in the circulating concentration of ANF after 1 week of weight reduction in both obese groups. Mean arterial pressure fell significantly in both groups, with the hypertensive group becoming normotensive during the first week of the diet. The marked changes in ANF and mean arterial pressure during the first week of the diet appeared related to reduced salt intake. Mean arterial pressure and ANF concentrations, however, continued to fall during the eighth to 12th week of weight reduction diet in the hypertensive patients when salt intake had been unchanged for several months. In both the hypertensive and normotensive subjects ANF paralleled blood pressure changes (r = .54, P less than .0001) throughout the 12-week study period. ANF was inversely correlated with plasma renin activity and aldosterone, with the most dramatic changes in their concentrations being during the first week of the diet. These results demonstrate that weight loss while ingesting a controlled low sodium diet is accompanied by changes in ANF that directly correlate with changes in blood pressure and inversely correlate with changes in the renin-aldosterone axis, which ANF is known to inhibit.     

Nocturnal continuous measurement of blood pressure in sleep apnea syndromes. Comparison between normotensive and hypertensive patients

Sleep apnea syndrome and systemic hypertension are frequently associated but their causal relationship is unclear. We compared the oscillations of systemic blood pressure and heart rate during polysomnography in 8 normotensive subjects (2 females) and 5 hypertensive (supine awake blood pressure: 165 +/- 7/96 +/- 5 mmHg) without treatment. Their ages (normotensive: 52.1 +/- 11.0 yrs, hypertensive: 51.2 +/- 6.4 yrs) and body mass indices (32.6 +/- 9.6 kg/m2 vs 33.2 +/- 5.2 kg/m2 respectively) were not statistically different. Systemic blood pressure was continuously monitored by a non invasive digital plethysmography (Finapres). Both groups had similar respiratory events indices (normotensive: 45.2 +/- 18.1/hr, hypertensive: 48.4 +/- 20.5/hr) and minimal oxygen saturations (79.4 +/- 9.1% vs 82.4 +/- 7.0% respectively). During apneas in slow-wave sleep were observed the minimal values for systolic and diastolic pressures which were significantly higher in hypertensive than in normotensive (138.2 +/- 9.6/83.2 +/- 16.1 mmHg vs 105.9 +/- 11.1/60.5 +/- 10.9 mmHg respectively). During resumption of ventilation maximal blood values were recorded which were also higher in hypertensive than in normotensive (185.0 +/- 13.8/113.2 +/- 21.5 mmHg vs 155.9 +/- 19.8/88.7 +/- 17.1 mmHg respectively) (p less than 0.05). Although absolute variations of blood pressure were similar, relative changes in systolic pressure were significantly higher in normotensive (p less than 0.05). Maximal heart rate was 76.8 +/- 6.2 bpm in normotensive and 76.6 +/- 3.9 bpm in hypertensive during resumption of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ambulatory blood pressure is still elevated in treated hypertensive diabetic subjects compared with untreated diabetic subjects with the same office blood pressure.

Ambulatory blood pressure, ABP, was determined every 15 min for 24 h (Spacelabs 5200 system) in 16 hypertensive diabetic subjects treated for high blood pressure. Office blood pressure (OBP) in these subjects (systolic BP greater than 160 mmHg and diastolic BP greater than 95 mmHg before treatment) had been reduced by treatment to the borderline range (systolic less than or equal to 160 mmHg and/or diastolic less than or equal to 95 mmHg). Sixty-five diabetic subjects with normal or borderline OBP were included as controls. The two groups had the same age (58 +/- 10 yrs in both groups), duration of diabetes (15 +/- 9 yrs), 24 hr microalbumin, and included the same percentage of subjects with moderate neuropathy (36% and 29%, NS). The two groups had the same OBP (138 +/- 16 mmHg and 140 +/- 16 mmHg systolic, NS, 84 +/- 9 mmHg and 84 +/- 13 mmHg diastolic, NS). In contrast, ambulatory BP was significantly higher in the treated group, when compared with the controls (123 +/- 13 mmHg and 133 +/- 23 mmHg systolic, P less than 0.025, 77 +/- 7 mmHg and 84 +/- 16 mmHg diastolic, P less than 0.015). The difference was significant both in daytime and in nighttime, and was more significant in nighttime (11 mmHg systolic, P less than 0.02, 9 mmHg diastolic, P less than 0.004) than in daytime (9 mmHg systolic, P less than 0.05 and 5 mmHg diastolic, P less than 0.05). Ambulatory heart rate was also significantly higher in the treated group, but only in daytime (7 b/min difference, P less than 0.02). The study demonstrated the need to survey and investigate ABP in treated hypertensive diabetic subjects.     

Status of home blood pressure measured in morning and evening: evaluation in normotensives and hypertensives in Japanese urban population.

To assess home blood pressure status in a Japanese urban population, we analyzed home blood pressure values in normotensive subjects determined by casual blood pressure (< 140/90 mmHg), hypertensive subjects without medication (> or = 140/90 mmHg) and treated hypertensive patients. The subjects (468 male, 232 female; mean age 41 years old) were recruited from a company located in Tokyo. Home blood pressure was measured with a semi-automatic device (Omron HEM-759P). Subjects were instructed to perform triplicate morning and evening measurements on 7 consecutive days. In the treated hypertensive group (n = 70), there was a significant difference between morning (139 +/- 12/88 +/- 9 mmHg) and evening (130 +/- 12/79 +/- 8 mmHg) home blood pressure. In the normotensive group (n = 558), however, only the diastolic blood pressure (DBP) component of the home blood pressure was significantly different between morning (115 +/- 13/72 +/- 9 mmHg) and evening (114 +/- 12/68 +/- 8 mmHg). In the nontreated hypertensive group (n = 72), casual blood pressure (145 +/- 14/92 +/- 9 mmHg) was higher than morning (138 +/- 16/89 +/- 11 mmHg) and evening (134 +/- 16/83 +/- 11 mmHg) home blood pressure, but no difference was seen between morning and evening systolic blood pressure (SBP). According to the reference value of the Japanese Society of Hypertension 2004 (SBP > or = 135 mmHg and/or DBP > or = 85 mmHg), 7.2% (systolic) and 8.7% (diastolic) of subjects in the normotensive group were classified as hypertensive by home blood pressure. Casual blood pressure in the treated hypertensive group was normal in 64.3% for SBP and 70.0% for DBP. However, their morning SBP (32.9%), morning DBP (40.0%), evening SBP (10.0%), and evening DBP (17.1%) were classified as hypertensive by home blood pressure. Furthermore, patients who were taking antihypertensive drug(s) only in the morning (n = 52) showed higher morning SBP (6 mmHg, p = 0.086) and morning DBP (6 mmHg, p = 0.005) than patients taking drug(s) by other administration schedules (n = 18), but no difference in evening home blood pressure was observed. In conclusion, a proportion of the subjects defined as normotensive by casual blood pressure were classified as hypertensive by home blood pressure in the present urban population. Furthermore, morning home blood pressure control in the treated hypertensive group classified as under control by casual blood pressure was insufficient, especially in patients who were taking medication only in the morning.     

Decrease in blood pressure and increase in total peripheral vascular resistance in supine resting subjects with normotension or essential hypertension

Hemodynamic changes in the supine resting position were investigated in 70 male subjects, consisting of 15 healthy volunteers with normotension (blood pressure of 113 +/- 7/70 +/- 5 mmHg, M +/- SD), 25 patients with borderline essential hypertension (143 +/- 12/90 +/- 6 mmHg) and 30 patients with established essential hypertension (166 +/- 13/108 +/- 6 mmHg). The supine position reduced blood pressure, heart rate, stroke volume and cardiac output (p less than 0.001), but increased total peripheral vascular resistance (p less than 0.001). The decrease in systolic blood pressure (p less than 0.01), stroke volume (p less than 0.05) and cardiac output (p less than 0.05), and the increase in total peripheral vascular resistance (p less than 0.01) were significantly greater in the borderline and established essential hypertensive groups than in the normotensive group. The results demonstrated that the decrease in blood pressure was due to a reduction in both heart rate and stroke volume, and that the decrease in stroke volume and increase in total peripheral vascular resistance seen in the supine position were greater in the hypertensive groups than in the normotensive group. These hyperresponses may contribute to the development and persistence of high blood pressure in patients with essential hypertension.     

Decreased central dopaminergic activity in essential hypertension

Baseline serum prolactin (PRL) was found to be similar in 35 men with untreated essential hypertension (149 +/- 2/98 +/- 1 mmHg; means +/- s.e.) and 44 healthy normotensive men (126 +/- 1/80 +/- 1 mmHg), all 40 years old. A correlation between baseline PRL and aldosterone was found in the normotensive (r = 0.534, P less than 0.001), but not in the hypertensive group (r = -0.011, NS). Ten subjects from each group received intravenous metoclopramide, a competitive dopamine antagonist, while another 12 normotensive subjects were given saline only, and the effect on PRL, vasopressin (AVP) and catecholamines was followed. An exaggerated PRL response to metoclopramide was observed in the hypertensive group compared with the normotensive (P less than 0.05), and the mean normotensive peak value never exceeded the hypertensive. Plasma noradrenaline increased significantly compared with baseline (P less than 0.05) and the control group (P less than 0.001), concomitant with increased heart rate (P less than 0.05), after the administration of metoclopramide both in the hypertensive and normotensive group. After intravenous injection of metoclopramide, forearm blood flow increased significantly by 50% in the hypertensive (P less than 0.001), and 80% in the normotensive group (P less than 0.001) compared with the control group. Mean blood pressure remained unchanged as did plasma AVP, dopamine and adrenaline. The present study indicates an altered central dopaminergic activity in essential hypertension. Even at rest, endogenous dopamine exerts a modulating effect on noradrenaline release in both hypertensive and normotensive men.     

Effect of low versus conventional dose cyclopenthiazide on platelet intracellular calcium in mild essential hypertension

Platelet free intracellular calcium levels were measured during a double-blind, placebo-controlled parallel study to investigate the antihypertensive activity of 50 micrograms, 125 micrograms, and 500 micrograms cyclopenthiazide, in mild essential hypertension. Cytosolic free calcium levels were significantly higher in established hypertensive patients (135 +/- 28 nmol/l, P less than 0.001) but not in borderline hypertensive patients (123 +/- 26 nmol/l) compared with normotensive controls (111 +/- 9 nmol/l). A positive correlation between platelet free calcium level and systolic and diastolic blood pressure was confirmed (n = 68; r = 0.309 P = 0.01; r = 0.405 P less than 0.001, respectively). The 125-micrograms and 500-microgram doses of cyclopenthiazide produced mean decrements in blood pressure of 18/10 mmHg and 23/8 mmHg, respectively, (P less than 0.05 for both), after 8 weeks of therapy. The 50-microgram dose displayed no useful antihypertensive activity. Platelet free calcium levels fell by a similar amount in the four groups. The fall in blood pressure produced by the 125 and 500-microgram doses of cyclopenthiazide did not correlate with changes in platelet [Ca2+]i (r = 0.166 systolic and r = 0.169 diastolic). These findings do not support the hypothesis that changes in platelet cytosolic calcium levels are determined by the same factors that control blood pressure.     

Optimal size of cuff bladder for indirect measurement of arterial pressure in adults

This study tested the hypothesis that a sphygmomanometer cuff bladder long enough to encircle the arm in most adults ('obese cuff') would provide a more accurate and precise estimate of intra-arterial pressure than the usual 'standard' cuff bladder. In 53 patients undergoing diagnostic coronary angiography (35 males, 18 females, aged 36-79 years), indirect blood pressure, measured in the left arm with a random-zero sphygmomanometer, was compared with simultaneously measured femoral intra-arterial pressure. Duplicate indirect measurements were made with each of two cuffs containing bladders measuring 39 x 15 cm ('obese') and 23 x 12 cm ('standard'). The obese cuff bladder encircled 80% or more of the arm circumference in all subjects, whereas the standard cuff bladder met this requirement in only 19% of the subjects. For both systolic and diastolic pressure there was marked interindividual variability in the differences between indirect and direct measurements with both cuffs. With the obese cuff there was no systematic error in the diastolic blood pressure measurement. The standard cuff consistently overestimated diastolic pressure by 7.7 +/- 8.3 mmHg (mean +/- s.d.). For both cuffs, the difference between indirect and direct diastolic pressure increased with arm size (P less than 0.05). Both cuffs underestimated systolic blood pressure, the obese cuff by 15.5 +/- 11.7 mmHg and the standard cuff by 7.6 +/- 12.1 mmHg. These systolic blood pressure underestimates were greater at higher blood pressures (P less than 0.01) and with smaller arms (P less than 0.05). Age was not related to measurement error with either cuff.(ABSTRACT TRUNCATED AT 250 WORDS)     

Haemodynamic contributions to post-exercise hypotension in young adults with hypertension and rapid resting heart rates.

The haemodynamic effects of 45 min of treadmill exercise (at 70% of resting heart rate reserve) were determined in 5 young adults with hypertension and rapid resting heart rates (greater than 90 beats/min in clinic) and were compared with those of 5 age-matched normotensive subjects. Blood pressure was lower after exercise in the hypertensive, but not the normotensive subjects. Mean cardiac output before exercise was similar in the two groups, and fell from 6.8 +/- 0.6 before to 5.4 +/- 0.6 l/min 60 min after exercise in the hypertensive group (P less than 0.01). Total peripheral resistance tended to be higher at this time. Neither variable was affected by prior exercise in the normotensive group. The depressor effects of prior exercise on mean arterial pressure (-8.6 +/- 1.0 vs. -1.4 +/- 2.5 mmHg; P less than 0.04) and cardiac output (-1.4 +/- 0.3 vs. -0.1 +/- 0.1 l/min; P less than 0.005) and the increase in total peripheral resistance (+3.0 +/- 1.2 vs. 0.0 +/- 1.0 Units; P less than 0.05) were greater in the hypertensive group. Thus, the post-exercise hypotension in this selected group of young hypertensive subjects with rapid resting heart rates was mediated by a decrease in cardiac output and stroke volume disproportionate to the fall in blood pressure, suggesting sustained compromise of their cardiac performance after acute exercise.     

Clinical evaluation of the Colin ABPM 630 at rest and during exercise: an ambulatory blood pressure monitor with gas-powered cuff inflation

The Colin ABPM 630 is a silent, gas-powered (CO2) ambulatory blood pressure monitor which uses both ausculatory and/or oscillometric methods to measure blood pressure. We compared simultaneous, same-arm blood pressures obtained with the monitor with those made by two blinded, skilled clinicians using a mercury column and teaching stethoscope. In a second study, the monitor readings were also compared with opposite-arm intra-arterial recordings of blood pressure. The group mean systolic blood pressures obtained by the Colin monitor via the Korotkoff mode were almost identical to the mercury column readings (127.8 +/- 19.4 versus 128.1 +/- 19.3 mmHg, P = NS) and the limit of agreement (2 standard deviations) for the differences in the two methods was +/- 9 mmHg. The diastolic blood pressure obtained by the Colin monitor was significantly lower than the clinician's readings (-6.0 +/- 5.9 mmHg, P less than 0.0001). Similar findings were obtained with the oscillometric mode, however, the mean systolic blood pressure given by the monitor was slightly higher than that given by the mercury column (1.9 +/- 4.5 mmHg, P less than 0.001). In contrast to the mercury column comparisons, the mean diastolic blood pressure obtained with the monitor was nearly the same as the mean intra-arterial diastolic blood pressure for both the Korotkoff (0.1 +/- 5.6 mmHg) and the oscillometric modes (1.2 +/- 6.3 mmHg). During 100-watt bicycle exercise, there was a considerably greater scatter in the individual comparisons of the monitor and intra-arterial blood pressure than that seen in the measurements at rest, but the group means were again similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Normotensive young men with family histories of hypertension gain weight and decrease their intraerythrocyte sodium content during a 5-year follow-up

Young normotensive men matched for age and body mass index with (n = 16) and without (n = 13) family histories of hypertension were investigated at baseline and after 5 years of follow-up with respect to blood pressure, body weight and intracellular sodium content. Subjects with positive family histories of hypertension increased significantly in body weight (from 81.9 +/- 11.5 kg to 89.5 +/- 11.4 kg, P less than 0.001) compared to subjects with negative family histories of hypertension (from 79.9 +/- 10.8 kg to 80.7 +/- 12.2 kg, NS). Their blood pressure did not differ initially (137 +/- 12/75 +/- 11 mmHg vs. 135 +/- 8/72 +/- 9 mmHg), but was reduced in subjects without family histories of hypertension (to 125 +/- 3/68 +/- 13 mmHg) in the follow-up examination. At follow-up, body mass index showed a positive correlation with blood pressure among subjects with positive family histories of hypertension (r = 0.77, P less than 0.001). At baseline, subjects with hypertensive fathers had significantly higher intraerythrocyte sodium levels than subjects with normotensive parents. At re-examination 5 years later, this difference was no longer present. We conclude that normotensive subjects with positive family histories of hypertension are predisposed to gain weight rather than to show an increase in blood pressure at this age. Normalization of intracellular sodium content, as found in the present study, could be a consequence of this weight gain and the ensuing metabolic adaption.     

Sleep disturbance during ambulatory blood pressure monitoring of hypertensive patients

BACKGROUND: Hypertensive patients who fail to exhibit a normal fall in blood pressure at night may have a greater risk of target-organ damage. Sleep, with associated cessation of physical activity, is the principal determinant of nocturnal blood pressure 'dip'. OBJECTIVE: To ascertain whether hypertensive patients, who experience the discomfort of higher cuff-inflation pressures during ambulatory blood pressure monitoring, experience more interference with sleep, manifested by greater nocturnal physical activity. DESIGN: A retrospective case- control study. METHODS: Subjects were selected from a database of 475 patients who had undergone simultaneous 24 h ambulatory blood pressure monitoring and monitoring of physical activity with a wrist-mounted piezoelectric accelerometer. Sixty-one hypertensives (average daytime systolic blood pressure >/= 150 mmHg) were age matched to 61 subjects with average daytime systolic blood pressures 相似文献   

Weight reduction decreases the circulating concentration of the N-terminus of the ANF prohormone.

The N-terminus of the atrial natriuretic factor (ANF) prohormone (ie, proANF 1-98) contains two vasodilatory peptides consisting of amino acids (aa): aa 1-30 (ie, proANF 1-30) and aa 31-67 (ie, proANF 31-67) of the 126 aa prohormone. The relationship of this N-terminus to the renin-aldosterone axis and blood pressure reduction was investigated in 18 obese subjects (5 hypertensive and 13 normotensive) placed on a 12-week, low sodium (40 mmol), weight reducing diet. The N-terminus of the ANF prohormone and proANF 31-67, which circulates as a distinct entity after being proteolytically cleaved from the N-terminus, were significantly (p less than 0.001) higher (767 +/- 1.01 and 816 +/- 135 fmol/ml) in the obese hypertensive group compared with the obese normotensive group (377 +/- 24 and 356 +/- 17 fmol/ml, respectively) prior to beginning the weight reduction program. There was a dramatic fall in the N-terminus and in proANF 31-67 after 1 week of weight reduction in both obese groups, which correlated with the decrease in mean arterial pressure during the first week and throughout the 12 weeks of weight reduction (r = .54, p less than 0.001 and r = .59, p less than 0.001, respectively). ProANF 1-98 had a significant (p less than 0.01) inverse correlation with plasma renin in both obese groups. ProANF 31-67, likewise, had an inverse correlation with plasma renin in the hypertensive (p less than 0.002), as well as the normotensive (p less than 0.03) subjects. ProANF 31-67 did not significantly correlate with aldosterone in either group.(ABSTRACT TRUNCATED AT 250 WORDS)     

A dietary fibre supplement and weight maintenance after weight reduction: a randomized, double-blind, placebo-controlled long-term trial

Ninety-seven mildly obese females (BMI = 27.4 kg/m2) were in a randomized, double-blind, placebo-controlled trial treated for 52 weeks. The treatment consisted of a hypocaloric diet providing 5000 kJ/day (1200 kcal) and a dietary fibre supplement of 7 g/day for 11 weeks, (part I), followed by a diet providing 6720 kJ/day (1600 kcal) and a dietary fibre supplement of 6 g/day for 16 weeks (part II). Finally placebo was withdrawn and all still adhering subjects were given a dietary fibre supplement of 6 g/day and an ad libitum diet for the rest of the period (part III). Initial body weights were comparable, 76.9 +/- 0.8 kg in the fibre group versus 77.7 +/- 1.3 kg in the placebo group. During part I the weight reduction in the fibre group of 4.9 kg was significantly higher compared to that of 3.3 kg in the placebo group (P = 0.05). Accumulated weight reduction during part II was still significantly higher in the fibre group, 3.8 kg, compared to 2.8 kg in the placebo group (P less than 0.05). Total weight loss in the fibre group after 52 weeks was 6.7 kg. Probability of adherence to the treatment regimen was significantly higher in the fibre group from week 13 and onwards (P less than 0.01). Initial blood pressures were comparable. A significant reduction of systolic blood pressure occurred in both groups. A significant reduction of diastolic blood pressure occurred in the fibre group only, from 85.4 +/- 1.2 mmHg to 81.7 +/- 1.1 mmHg (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)