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Biomedical subjects

H Rüddel

Publications and source records attributed to H Rüddel.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Significance of microproteinuria for early detection of hypertension-induced end organ damage].

To investigate the clinical importance of microproteinuria, we examined the prevalence of microproteinuria and its relation to cardiac structural adaptation in 80 male, middle-aged patients with essential hypertension. Patients with secondary causes of hypertension were ruled out. 14 out of 80 hypertensives (18 percent) were found to have microproteinuria defined as "negative" for urinary protein excretion in the conventional test, but "positive" (above the upper normal limit) in the 24-hour urine samples. Patients with microproteinuria had a similar age and body weight, but a higher systolic and diastolic pressure (161 +/- 14/104 +/- 12 vs 148 +/- 14/97 +/- 9 mmHg, p less than 0.02) and greater creatinine clearance (163 +/- 36 vs 136 +/- 33 ml/min, p less than 0.01) than those with normal protein excretion. Also, hypertensives with microproteinuria had a greater left ventricular mass (241 +/- 57 vs 207 +/- 45 g, p less than 0.05) and greater cross sectional area (22.2 +/- 2.8 vs 20.5 +/- 2.9 cm2, p less than 0.05) evaluated by 2-D guided M-mode echocardiography than the control group. A positive Sokolow-index was more prevalent in patients with microproteinuria than in those without (x2 = 6.2, p less than 0.02). Patients with essential hypertension and microproteinuria (prevalence 21 per cent) were characterized by a higher arterial pressure, by a higher degree of echocardiographic and electrographic evidence of left ventricular hypertrophy. Thus, microproteinuria might serve as a marker for early target organ damage in essential hypertension.

Adult↗
PubMed1990

Changes in blood pressure and heart rate during passive upright tilt upon electrical carotid sinus nerve stimulation.

Electrical carotid sinus nerve stimulation was applied in three normotensive anginal patients and one hypertensive patient during upright tilting. Despite a base-line depressor response to continuous stimulation, orthostatic hypotension was not augmented. In individual patients stimulation slightly enhanced the fall of systolic pressure and delayed the increase of diastolic pressure immediately after tilting. Base-line heart rates and cardio-acceleration upon tilting remained almost uninfluenced by stimulation. It is concluded that a moderately enhanced carotid baroreceptor afferent nerve traffic did not interfere with the regular orthostatic response.

Blood Pressure↗
PubMed1990

Relation of hemodynamic reaction during stress to left ventricular hypertrophy in essential hypertension.

To elucidate the impact of increased afterload during physical and mental stress on myocardial hypertrophy, a homogeneous population of 73 patients with untreated mild-to-moderate essential hypertension were enrolled in the current study. Left ventricular mass and cross-sectional area, both determined by 2-D guided M-mode echocardiography, were related to blood pressure measured at rest as well as during various stress situations. Left ventricular mass and cross-sectional area correlated with systolic pressure at work site (r = 0.28 and r = 0.23 respectively, P less than .05) and systolic pressure at complete rest (r = 0.35 and r = 0.33, P less than .01). Neither the response in blood pressure to mental arithmetic or a bicycle exercise test performed in the laboratory, nor blood pressure during both stress tests were significantly related to the degree of left ventricular hypertrophy. In addition, patients with a hyperreactive response to mental arithmetic or to the physical stress test did not disclose a greater left ventricular mass than normoreactors. Examining the hemodynamic response pattern during mental arithmetic, we found that patients with vasoconstriction during mental stress had a greater left ventricular mass than individuals with vasodilation during mental stress (244 +/- 73 v 204 +/- 53 g, P less than .05), but this was due to the impact of obesity on left ventricular mass (analysis of covariance: F = 2.1, P = NS). Thus, blood pressure at work site and at rest, but not blood pressure during mental or physical stress, nor the response of blood pressure to both stress tests, was linked to the degree of left ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
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↗
PubMed1990

Impact of magnesium supplementation on performance data in young swimmers.

We examined whether healthy young swimmers improved performance during emotional and physical stress testing in the laboratory or during competition. Twenty four well trained healthy Caucasian pupils (14 boys and 10 girls, means = 16 years) were randomly treated either with 20 mmol Mg-aspartate-HCl/d or placebo for 3 months. After Mg supplementation serum Mg increased from 0.85 +/- 0.03 to 0.89 +/- 0.06 mmol/litre (P less than 0.05). Mg in red blood cells remained unchanged (4.79 +/- 0.35 mmol/kg dry weight before supplementation and 4.96 +/- 0.27 three months later, P = 0.32) whereas no increase in serum Mg or Mg in red blood cells was found in subjects who received placebo. Student's t test and analyses of variance revealed no significant differences in performance data either in the laboratory or during competition after supplementation with Mg.

Adolescent↗
PubMed1990

[Determinants for myocardial hypertrophy in mild essential hypertension. The effect of sodium chloride on left-ventricular hypertrophy].

The impact of clinical parameters on the pathogenesis of myocardial hypertrophy was examined in 75 male patients with mild essential hypertension. Clinical parameters were age, body weight, sodium excretion (as an estimate for dietary salt intake), systolic and diastolic blood pressure at work, casual blood pressure, resting and stress blood pressure during mental stress test and physical exercise. Left ventricular mass as a parameter for the degree of left ventricular hypertrophy was assessed by 2-D guided M-mode echocardiography. Left ventricular mass correlated with body weight (r = 0.47, p less than 0.002), with body mass index (r = 0.48, p less than 0.001), with systolic blood pressure at the worksite (r = 0.28, p less than or equal to 0.05), and systolic blood pressure at rest (r = 0.35, p less than or equal to 0.01), whereas no correlation was found between casual or stress blood pressure readings during physical exercise and mental stress with the degree of left ventricular hypertrophy. Sodium excretion was related to the end-diastolic diameter of the left ventricle (r = 0.33, p less than or equal to 0.01) and to left ventricular mass (r = 0.35, p less than or equal to 0.01). Multiple regression analysis revealed that sodium excretion over 24 hours, systolic blood pressure at the worksite and body mass index were independent determinants of left ventricular mass. Thus, dietary salt intake was found to modulate the degree of left ventricular hypertrophy independently of the pressure load imposed on the myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Sodium intake modulates left ventricular hypertrophy in essential hypertension.

In order to assess the impact of dietary sodium intake on the degree of left ventricular hypertrophy, we determined posterior wall thickness, relative wall thickness and left ventricular mass by two-dimensionally guided M-mode echocardiography, and related these parameters to sodium excretion over 24 h. There was no restriction on sodium intake. The first cohort comprised 43 subjects (residents of New Orleans) with mild to moderate essential hypertension who had not been treated for at least 4 weeks; in this cohort sodium excretion correlated with posterior wall thickness (r = 0.64, P less than 0.001), relative wall thickness (r = 0.67, P less than 0.001) and left ventricular mass (r = 0.37, P less than 0.02). A stepwise multiple regression analysis confirmed that sodium excretion was a determinant of posterior wall thickness (P less than 0.02) and relative wall thickness (P less than 0.05) independently of age, arterial pressure and body weight. The second cohort comprised 60 white male patients (residents of Bonn) with mild essential hypertension who had never been treated in the past; in this cohort sodium excretion correlated with diastolic diameter (r = 0.36, P less than 0.001) and with left ventricular mass (r = 0.35, P less than 0.001). Sodium excretion and systolic pressure emerged as independent variables (P less than 0.02) for left ventricular mass as evaluated by multiple regression analysis. These results identify dietary sodium intake as an independent powerful determinant of left ventricular hypertrophy in two disparate patient cohorts. Thus, for a similar haemodynamic load, sodium intake might accelerate, and conversely salt restriction mitigate, cardiac structural adaptation in patients with essential hypertension.

Cardiomegaly↗
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

Assessment of baroreceptor reflex sensitivity by means of spectral analysis.

A method of determining baroreceptor reflex sensitivity is proposed that is based on spectral analysis of systolic pressure values and RR interval times, namely, the modulus (or gain) in the mid frequency band (0.07-0.14 Hz) between these two signals. Results using this method were highly correlated (0.94; n = 8) with results of the phenylephrine method. In addition, compared with the values for the preceding rest period, the modulus decreased during mental challenge, as might be expected from the literature.

Adult↗
PubMed1987

Hemodynamic and neurohumoral effects of low-dose clonidine in mild to moderate hypertension.

To evaluate the role of the sympathetic nervous system in essential hypertension and the influence of clonidine, 28 male subjects with mild to moderate hypertension were either treated with low-dose clonidine (n = 14, mean age: 42.4 +/- 2.1 years) or were randomized to a nontreated control group (n = 14, mean age: 40.2 +/- 2.4 years). Clinical blood pressure and heart rate were assessed, and after 4 weeks of treatment plasma catecholamines and the hemodynamic response to mental arithmetic, cold stimulation, and ergometric exercise were compared between both groups. Under therapy with 0.075 mg of clonidine per day casual blood pressure dropped and diastolic BP was significantly lower than in the control group. Heart rate did not change. After 4 weeks the plasma levels of epinephrine and norepinephrine were the same in both groups. During mental arithmetic total peripheral resistance decreased in the treated group while it did not change in the control group, but both groups did not differ in their percentage changes in the hemodynamic parameters in response to the three stress tests. It has been concluded that clonidine reduces sympathoadrenergic activity, but in a low dosage this effect is obviously restricted to a reduction of arteriolar tone.

Adult↗