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Biomedical subjects

W Langewitz

Publications and source records attributed to W Langewitz.

At least 37 records · Page 2Linked to original sources
PubMed1992

[Long-term 24-hour blood pressure measurement in genuine gestosis and hypertensive pregnancy].

The clinical implications of diminished circadian blood pressure variations during hypertensive pregnancies are not fully understood. We used the COS-INOR-method to quantify circadian blood pressure amplitudes of 32 patients with preeclampsia (GG) and 21 patients with superimposed pre-eclampsia (PG). The two groups did not significantly differ in body weight, age, and gestational date at admission. No differences could be detected in 24-h blood pressure values between the two groups (GG: 127 +/- 14/82 +/- 12 mmHg, PG: 128 +/- 16/86 +/- 9 mmHg). Circadian amplitudes of systolic blood pressure variations (GG: 5.9 +/- 5.5 mmHg, PG: 4.5 +/- 6.9 mmHg) and diastolic blood pressure variations (GG: 3.8 +/- 3.0 mmHg, PG: 5.3 +/- 4.1 mmHg) did not differ significantly. The slope between successive changes of mean arterial blood pressure and successive changes in heart rate was significantly higher in patients with superimposed pre-eclampsia (GG: 0.16 +/- 0.27 mmHg/bpm, PG: 0.36 +/- 0.24 mmHg/bpm, p less than 0.005). We conclude that patients with pre-eclampsia and superimposed pre-eclampsia do not differ in 24-h blood pressure and circadian blood pressure variability, however, if blood-pressure variability is related to heart-rate variability differences become apparent that might be due to altered blood-pressure regulation.

Adult↗
PubMed1991

Impact of dilevalol on haemodynamic changes during emotional stress.

The effect of a single dose of 200 mg dilevalol, beta-adrenoceptor blocker with additional vasodilating properties, and 200 mg oxprenolol on haemodynamic changes induced by emotional stress have been compared in 12 male young Caucasian patients with newly diagnosed labile hypertension. No difference was noted in the stress-induced increase of total peripheral resistance (TPR) following administration of the two substances (11% versus 6%). However, dilevalol revealed a vasodilating action by decreasing TPR at rest (from 1004 to 951 dyn.s.cm-5) and diastolic blood pressure (BP) (from 87 to 75 mm Hg) whereas TPR at rest remained unchanged after the intake of oxprenolol.

Blood Pressure↗
PubMed1991

Changes in sympathetic and parasympathetic cardiac activation during mental load: an assessment by spectral analysis of heart rate variability.

Spectral analyses of heart rate (HR) and blood pressure (BP) fluctuations yield three typical peaks at a low (0.02-0.06 Hz), a mid (0.07-0.14 Hz) and a high (around the respiratory frequency) frequency area. These so-called bands attract the interest of researchers because they seem to offer the facility of non-invasively studying autonomic cardiovascular control mechanisms. The high frequency component is solely under vagal control, the influence of sympathetic/vagal efferents on the low and mid frequency band is unclear. We therefore investigated in a single case study (23 year old male) the effects of propanol (0.06 mg/kg, 30 min. interruption, 0.12 mg/kg i.v.), dobutamine (1.14 micrograms/kg/min for 30 minutes, then 2.21 micrograms/kg/min i.v., then 4.42 micrograms/kg/min), atropine (0.01 mg/kg within 5 minutes, 30 minutes later 0.02 mg/kg within 5 minutes), and carbachol (0.125 mg, 30 min. interruption, 0.25 mg s.c.) upon HR, HR-variability spectra, BP and respiratory parameters at rest and during 5 minutes of a mental task. Under all four drug conditions BP is elevated at rest and mental stress, the latter always giving higher results than the former. Atropine shortens interbeat intervals (IBI) by almost 50 percent (from 939 msec to 514 msec), the high dose of dobutamine reduces IBI from 725 to 580 msec, propranolol increases interval length by 10 percent. Drug effects on spectral bands give clear results with atropine: It reduces spectral energy in all three frequency bands at rest and during mental stress. The other drugs show no clear-cut effects on HR-variability spectra. Even though results of a single case study should be interpreted with great caution we believe that the following conclusion can be made: At rest and during short-lasting mental stress all frequency bands in HR-variability spectra are to a large extent under parasympathetic control.

Adult↗
PubMed1991

[Psychosocial risk factors and coronary heart disease].

A literature review shows that besides the classical risk factors smoking, hypercholesterolemia, hypertension and age psychosocial risk factors have been identified in the development and progress of coronary heart disease. They can be divided into four categories: inadvertent socio-economic conditions, insufficient physical exercise, type-A personality and emotional problems and lack of social support.

Coronary Disease↗
PubMed1990

[Psychotropic effects of captopril? Effect of a short-term treatment on reaction and concentration capabilities and space perception ability].

In a randomized, placebo-controlled double-blind trial 22 healthy normotensive young men (mean age 25 +/- 1.7 years) were given a single oral dose of 50 mg captopril or a placebo (11 subjects each). To test their concentration and proficiency, as well as spatial perception and reaction capacity four tests were administered: attention, concentration, hose-pattern perception and "Bonn Determination Device". Captopril had no negative effects on any test performances either one or five hours after its administration, or after a single daily dose for seven days. There was only a small, statistically not significant, difference in the effect on blood pressure between captopril and the placebo.

Adult↗
PubMed1990

Efficacy of long-term antihypertensive therapy with enalapril.

We examined whether long-term antihypertensive monotherapy with enalapril decreased clinical casual blood pressure (BP) as well as BP at work and during stress, and whether this angiotensin-converting enzyme (ACE) inhibitor had an adverse effect on the physiologic hemodynamic pattern during experimental mental stress. Seventeen male patients with hitherto untreated mild-to-moderate essential hypertension (mean age: 47 +/- 8 years) had 24-hour BP monitored noninvasively with the Physioport system before and during treatment with enalapril (5-10 mg/day) for 6 months. They also had a mental stress test, physical exercise test, and the cold pressor test before and after therapy. After the diagnostic observation period, average clinical casual BP was 150 +/- 12/102 +/- 7 mg Hg. Average BP at work, stress BP during all types of stimulation in the laboratory, and clinical casual BP significantly decreased during monotherapy with enalapril. Neither the circadian rhythm nor the hemodynamic pattern during mental stress was significantly altered by enalapril. BP increases during emotional stress were not significantly attenuated by the ACE inhibitor. These results demonstrated that enalapril effectively lowers BP without altering the physiologic hemodynamic pattern during emotional stress.

Adult↗
PubMed1989

Efficacy of four antihypertensive drugs (clonidine, enalapril, nitrendipine, oxprenolol) on stress blood pressure.

The impact of 4 antihypertensive drug regimens on blood pressure (BP) during everyday life stress and on BP during experimental stress in the laboratory was examined in an open clinical study. Sixty middle-aged men with mild-to-moderate essential hypertension never previously treated were treated either with low-dose clonidine (n = 10), oxprenolol (n = 20), nitrendipine (n = 20) or enalapril (n = 10). Before therapy, all 4 groups did not differ in age, weight, degree of obesity, BP at work site and casual BP measured in the outpatient clinic. After 6 months of effective therapy (casual BP within the normotensive range), casual diastolic BP was identical among the 4 groups, whereas systolic BP was lower in patients treated with clonidine or oxprenolol than in those who received enalapril. A disparate pattern of antihypertensive efficacy among the 4 groups emerged when stress BP was compared, with average ambulatory BP higher in patients receiving clonidine or enalapril than in those who had oxprenolol or nitrendipine. During ambulatory BP monitoring, patients treated with oxprenolol had the lowest level at each level of physical activity and self-reported emotional arousal. During bicycle exercise, patients receiving clonidine had the highest increase in systolic BP and those administered oxprenolol the lowest, whereas the BP response during mental stress was similar among all 4 therapeutic groups. The analysis of the hemodynamic response pattern during mental stress unmasked further disparities. Oxprenolol provoked an abnormal hemodynamic response during mental stress tests (increase in total peripheral resistance), whereas nitrendipine and enalapril preserved the physiological hemodynamic profile (decrease of total peripheral resistance).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The reliability of psychophysiological examinations under field conditions: results of repetitive mental stress testing in middle-aged men.

In an epidemiological examination outside specialized laboratories we investigated the test-retest stability of blood pressure (BP) and heart rate (HR) reactions to standardized mental stress in 136 men (mean age 44 +/- 7 years) with complaints of mental and physical fatigue. Repetitive stress testing was performed at 4-week intervals on four occasions. On all four occasions stress levels differed significantly from baseline levels (P less than 0.001). Baseline conditions for BP and HR were significantly correlated at 4-week and 8-week intervals (P less than 0.001). Cardiovascular reactivity to mental stress was also stable over a 4, 8, and 12-week period. We conclude that psychophysiological reactivity can be assessed with good reliability under field conditions.

Adult↗
PubMed1989

Spectral analysis of heart rate variability under mental stress.

It has been claimed that an increase in the 0.1-Hz component in power spectra of heart rate variability indicates an increased sympathetic tone. We tested 135 middle-aged unmedicated men (mean age 44 +/- 7 years) with two types of mental tasks, a reaction-time test and a mental arithmetic test, to determine whether the results were comparable with those from tilt tests. Although both tasks significantly increased the heart rate and blood pressure, to the same extent as the tilt tests, energy in the 0.1-Hz band decreased during the reaction-time test (from 899 +/- 641 to 482 +/- 430; P less than 0.01) yet was unchanged during the mental arithmetic test. We conclude that the response of the 0.1-Hz component is a task-specific phenomenon.

Blood Pressure↗
PubMed1989

Disparities in blood pressure control under various antihypertensive regimens.

Ambulatory blood pressure recordings and stress blood pressures during exercise were compared among hypertensive patients effectively treated with oxprenolol, nitrendipine, enalapril or low-dose clonidine. After 6 months of therapy, the means of blood pressure at rest and casual diastolic pressure were nearly identical among the four therapeutic groups. Although all pressures fell to within the normotensive range, casual systolic pressures were lower in patients treated with sympatholytic agents than in those taking enalapril. In contrast, average ambulatory blood pressure was less controlled in patients given clonidine or enalapril than in those given oxprenolol or nitrendipine. During physical stress patients taking clonidine showed the highest stress blood pressures and those taking oxprenolol the lowest pressures. The study demonstrated that although blood pressure was reduced to within the normotensive range in all four therapeutic groups, analysis of values of ambulatory blood pressure and stress blood pressure during physical activity showed a disparate pattern of antihypertensive efficacy.

Antihypertensive Agents↗
PubMed1989

Standardized stress testing in the cardiovascular laboratory: has it any bearing on ambulatory blood pressure values?

We examined 77 males (mean age 45 years; mean casual blood pressure 139/94 mmHg; no secondary hypertension) to evaluate the relationship between cardiovascular measures from standardized stress testing (mental arithmetic, cold pressor test) in the laboratory and 24-h ambulatory recordings of blood pressure and the heart rate. The basic relationship between laboratory and ambulatory recordings was calculated by correlating the mean of our laboratory values with 24-h mean ambulatory values. Laboratory readings of baseline and stress systolic blood pressure, diastolic blood pressure and the heart rate correlated significantly (P less than 0.05) with ambulatory recordings of 24-h means and short-period means (e.g. baseline systolic blood pressure with work mean, r = 0.33; with mean, r = 0.33). However, the correlations were no closer than the basic relationship between laboratory examinations and ambulatory recordings (r = 0.41 for systolic blood pressure; r = 0.46 for diastolic blood pressure; r = 0.43 for heart rate). There was no specifically close correlation between laboratory baseline and the corresponding ambulatory rest phase (evening, sleep) or between laboratory stress values and ambulatory phases of high demand (work mean). Reactivity measures in the laboratory (stress values-baseline values) were correlated to measures of variability in ambulatory recordings (standard deviation; coefficient of variation; maximum, minimum value; range), but, again, there was no specific effect separating similar from non-similar phases. We conclude that laboratory measures have no specific bearing on ambulatory blood pressure and heart rate measures.

Blood Pressure Determination↗
PubMed1989

Comparison of parameters for assessing blood pressure and heart rate variability from non-invasive twenty-four-hour blood pressure monitoring.

Cardiovascular psychophysiologists often express variability in successive data as the root of the mean squared successive differences. Other parameters of variability, such as the standard deviation and the coefficient of variation, are largely determined by slow (such as circadian) rhythms or linear trends. When the parameters of variability in blood pressure data are calculated each hour over an increasing period of time (to simulate the termination of the blood pressure monitoring after a variable duration), standard deviations and coefficients of variation increase due to the decrease in blood pressure levels at evening and night, but the root of the mean squared successive differences does not. The advantage of using the root of the mean squared successive differences as a parameter of blood pressure variability is shown in data from 147 outpatients with 10784 blood pressure readings.

Adult↗
PubMed1988

Hemodynamic response patterns to mental stress: diagnostic and therapeutic implications.

Stress has been identified as contributing to the development of cardiovascular disease. The pathophysiologic link between stress and disease still remains unclear. Because experimental stress testing in the laboratory permits the examination of the underlying mechanism for stress-induced blood pressure, analyses of cardiovascular reactivity during emotional stress could be of particular clinical importance. The analyses of pooled data during the past 6 years (n = 298, age from 20 to 60 years, normotensive subjects as well as patients with borderline and mild essential hypertension) reveal that stress-induced changes in stroke volume and especially in total peripheral resistance are crucial parameters to analyze the hemodynamic stress response. However, neither those simple nor complex response patterns such as "hot reactor" describe clinically distinct subgroups of persons. When physiologic testing was repeated in hypertensive patients after effective long-term antihypertensive therapy with clonidine, oxprenolol, nitrendipine, or enalapril, no attenuation of the stress-induced increase in blood pressure was found in any of these groups. However, heart rate reactivity and stress-induced changes in total peripheral resistance were altered significantly by oxprenolol and nitrendipine. The beta-adrenoceptor blocker decreased heart rate reactivity and increased reactivity of peripheral resistance; the calcium antagonist decreased stress-induced changes in peripheral resistance and increased the heart rate response. The centrally acting sympatholytic regimen and the angiotensin-converting enzyme inhibitor had no impact on the hemodynamic response pattern during emotional challenge.

Adult↗
PubMed1988

Impact of antihypertensive therapy on blood pressure reactivity during mental stress.

The effects of baseline antihypertensive drugs or sympatholytic agents on the characteristic hemodynamic response pattern (i.e. increase in blood pressure and heart rate, decrease in total peripheral resistance) during emotional stress were examined. Middle aged male caucasian patients with hitherto untreated mild essential hypertension were given nitrendipine 10-20 mg per day, oxprenolol 160 mg per day or clonidine 75-300 micrograms per day until casual blood pressure was below 140/90 mmHg for at least three months. Blood pressure, heart rate and stroke volume was assessed, at rest and during emotional stress, before and during effective antihypertensive therapy. The increase in systolic pressure during stress was not attenuated by any of the drugs. Heart rate reactivity was lowest when patients received oxprenolol, but peripheral resistance during emotional stress was significantly increased. Clonidine had no unfavorable effects on the hemodynamic pattern during emotional stress but nitrendipine decreased peripheral resistance even more than the decrease in resistance observed during stress before initiation of therapy. If one accepts that antihypertensive therapy should not alter a physiological hemodynamic pattern to an unphysiological response, psychophysiological examinations seem to be valid in selecting suitable patients for the different alternatives in antihypertensive therapy.

Adult↗
PubMed1987

Psychophysiologic aspects in essential hypertension.

Epidemiologic and experimental studies disclosed that the sympathetic nervous system might play a pivotal role in the pathogenesis of essential hypertension. Although systolic pressure exhibits a weak endogenous rhythm, diurnal fluctuations of arterial pressure are provoked primarily by physical or emotional stress factors. The magnitude of the cardiovascular response, however, varies widely from individual to individual. Subjects at high risk of future hypertension,--such as those with a positive history of familial hypertension, high resting heart rate, or transient increase in arterial hypertension--revealed blood pressure hyperresponsiveness to stress stimuli mediated by an overreactivity of the sympathetic nervous system. Furthermore, cardiovascular reactivity to mental arithmetic tasks and to traffic noise put a patient at high risk of developing arterial hypertension. In women, exaggerated cardiovascular response to stress stimuli appeared to be mitigated by estrogens, whereas oral contraceptives overrode this 'protective' effect of estrogens. At a certain point, repeated episodes of high stress blood pressure could produce structural vascular changes finally inducing sustained hypertension.

Arousal↗
PubMed1987

Influence of perceived level of stress upon ambulatory blood pressure, heart rate, and respiratory frequency.

The hypothetical advantage of ambulatory blood pressure (BP) recordings over clinical casual BP readings is based on the assumption that it reflects the impact of daily life stress. We investigated the relation of ambulatory BP, heart rate (HR), and respiratory frequency (RF) readings to environmental conditions (work vs. home) and to the perceived level of stress (from 1 = completely relaxed to 5 = extremely stressed) in 34 healthy employed subjects. Systolic and diastolic BP (129 vs. 120 mmHg; 89 vs. 82 mmHg), RF (18 vs. 16 resp/min) and perceived stress (2.3 vs. 1.6 a.u.) differed significantly between work and home. ANOVA revealed a significant effect of perceived stress on SBP (F = 7.87; p less than 0.001), DBP (F = 8.73; p less than 0.001), and HR (F = 7.23; p less than 0.001).

Adult↗