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Biomedical subjects

R Schmieder

Publications and source records attributed to R Schmieder.

32 records · Page 2Linked to original sources
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

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↗
PubMed1987

How to perform mental stress tests.

To study the phenomenon of cardiovascular hyperreactivity it is essential to know the impact of stimulus intensity and the effects induced by repeated exposure to a stressful situation like a mental arithmetic task. All subjects in this study were young healthy male students. Two different mental stressors were used: a mental arithmetic task with low stimulus intensity and one with high stimulus intensity characterised by more challenging instructions, a more competitive situation, and exposure to affective noise. The lower level mental test did not disclose any differences in the hemodynamic response in the subjects. Only the mental stress test with high stimulus intensity proved capable of detecting the cardiovascular hyperreactivity in normotensive subjects with familial hypertension. As hemodynamic response was attenuated during the second mental stress test if the second test was the lower stimulus test, and since repeated stress testing is necessary when prospective or intervention studies are performed, the stimulus intensity and sequence of mental stress tests had to be controlled carefully. To counteract any cardiovascular adaptation, it is suggested that the stimulus intensity of mental stress tests should slightly increase when repeatedly applied.

Adult↗
PubMed1986

Left ventricular hypertrophy. A cardiovascular risk factor in essential hypertension.

The heart adapts to increasing afterload, such as that which occurs in arterial hypertension, with an increase in wall thickness in order to bring wall stress back to normal. As a consequence, concentric left ventricular hypertrophy ensues. Hypertension as well as advancing age has been shown to be associated with an increase in posterior wall thickness. Accordingly, the prevalence of left ventricular hypertrophy becomes very high in the elderly and may occur in more than 50% of elderly hypertensive patients. Left ventricular hypertrophy is not merely a physiological process serving to compensate for the increased afterload. The Framingham study has indicated that patients with left ventricular hypertrophy are at an increased risk of sudden death and other cardiovascular morbidity and mortality. The risk for sudden death is 5 to 6 times higher in patients with left ventricular hypertrophy than in those without, regardless of levels of arterial pressure. By Holter monitoring of these patients it has been shown that those with left ventricular hypertrophy have a prevalence of premature ventricular contractions that is 40 to 50 times higher than those patients without left ventricular hypertrophy. In addition, patients with left ventricular hypertrophy rated substantially higher with regard to Lown's classes than those without. These data indicate that left ventricular hypertrophy is common, particularly in the elderly, and predisposes to ventricular ectopy, higher grade arrhythmias, and sudden death. Clearly, these considerations have to be taken into account when selecting antihypertensive therapy inasmuch as hypokalaemia, hypomagnesaemia, and other electrolyte shifts predisposing to ventricular arrhythmias must be scrupulously avoided.

Age Factors↗
PubMed1985

Reliability and validity of ambulatory blood pressure recording in children.

We investigate whether ambulatory BP (aBP) recording in children reflects situational variations and whether aBP depicts the impact of heightened cardiovascular reactivity under mental challenge, and gender on changes in BP. Results of 19 aBP protocols (2 to 7.30 p.m. after school; 30 min intervals) in 86 children, performed during 2 years of follow-up show that repetitive ambulatory blood pressure (aBP) recording reflects the great variability of environmental stimuli in children. Mean aBP is highly correlated with self-reported physical activity. Systolic aBP correlates with cardiovascular changes under mental arithmetic and - to a lesser degree - during bicycle exercise. Ambulatory BP recording is a sensitive method to detect the influence of hyperreactivity and gender on BP development in children at the age of 10-13 yrs.

Ambulatory Care↗
PubMed1985

The influence of monotherapy with oxprenolol and nitrendipine on ambulatory blood pressure in hypertensives.

We investigated whether beta-blockers or calcium-antagonists might be preferred in baseline antihypertensive therapy. In middle-aged male patients with essential BP readings did not differ between patients on Oxprenolol or on Nitrendipine (average BP: 123 +/- 12/81 +/- 14 vs. 129 +/- 17/80 +/- 10 mmHg), when clinical casual BP was within the normotensive range. Average BP at work was lower than clinical casual BP taken at the same day (125 +/- 14/80 +/- 12 vs. 133 +/- 12/87 +/-13 mmHg). A linear dependency between SBP at work and level of self reported physical activity (F(3,413) = 7.6; p less than or equal to 0.001) and arousal was found (F(3,374) = 5.2; p less than or equal to 0.02). Patients on Oxprenolol consistently had lower SBP at a particular level of physical activity and at lower levels of arousal than patients on Nitrendipine. We conclude that both regimen were equally effective as baseline antihypertensive monotherapy.

Adult↗
PubMed1984

Efficacy of nitrendipine as baseline antihypertensive therapy.

To determine whether calcium antagonists might be used alternatively to beta-blockers in antihypertensive therapy, we investigated if monotherapy with oxprenolol (160-320 mg/day) and nitrendipine (20-40 mg/day) were equally effective on clinical casual blood pressure (BP), ambulatory BP monitoring (Remler), and BP during mental challenge (video game). In a prospective randomized long-term study, 60 white male civil servants (mean +/- SD = 43 +/- 6 years) with mild essential hypertension only were treated for at least 4 months. Average BP before therapy was 149 +/- 11/97 +/- 11 mm Hg. The antihypertensive effect was not different between the two groups (19/14 versus 21/12 mm Hg). Both groups did not differ in BP at rest, in BP during mental challenge (141 +/- 7/109 +/- 5 versus 146 +/- 9/112 +/- 8 mm Hg, NS), and average ambulatory BP monitoring at work (122 +/- 12/81 +/- 17 versus 132 +/- 14/79 +/- 17 mm Hg, NS), which was identical with the clinical casual BP. Thus, nitrendipine can effectively be used in long-term baseline antihypertensive monotherapy.

Adult↗
PubMed1983

The influence of beta blockers on cardiovascular reactivity and Type A behavior pattern in hypertensives.

The influence of beta blockers on Type A behavior pattern and cardiovascular reactivity was tested. Nineteen white, male hypertensive patients were divided at random into two therapeutic groups (100 mg atenolol versus 50 mg hydrochlorothiazide + 5 mg amiloride (control group) ). For each patient, the German version of the structured interview was performed before therapy and at a minimum of 4 weeks after normalization of clinical resting casual blood pressure (BP). Prior to therapy, there were no differences in age, BP at rest, cardiovascular reactivity, and Type A between the two groups. After therapy, the patients treated with beta blockers changed Type A characteristics toward Type B, regardless where they started on the Type A scale, and beta blockers attenuated cardiovascular reactivity. In this study, Type A (hypertensive patients) was not associated with greater cardiovascular reactivity.

Amiloride↗
PubMed1982

Effects of beta-blockers on type-A coronary-prone behaviour.

The influence of coronary-prone behaviour on coronary heart disease is well established, but the link between behavioural and pathophysiological processes is still unknown. A beta-adrenergic hyper-reactivity of type-A subjects is assumed. In this investigation the influence of beta-blockers on the type-A behavior pattern was tested in an inter-individual comparison. Sixteen male hypertensive subjects (stage I or II) were divided at random into two therapeutic groups (beta-blockers vs diuretics). Each patient was given a type-A interview before therapy and at a minimum of 4 weeks after the onset of therapy. Subjects in both groups were similar in age and before therapy they had similar blood pressure at rest as well as similar cardiovascular reactivity and type-A behaviour pattern. After therapy, subjects in the group treated with beta-blockers exhibited less type-A behaviour than those in the group treated with diuretics. The possible influence of the attenuation of the type-A behaviour on the risk of coronary heart disease should be investigated in a prospective study.

Amiloride↗
PubMed1982

Cardiovascular reactivity during mental stress testing, the type A interview, and exercise testing in healthy male subjects.

We compared the blood pressure (BP) of 61 healthy male Ss during mental arithmetic plus noise, physical exercise testing and the Type A interview. A consistent association between personality characteristics and cardiovascular reactivity was not found. There was a consistent correlation between systolic BP reactivity during mental arithmetic and the Type A interview. Mental arithmetic and exercise testing correlated significantly for middle aged men. No correlation of BP was found between the Type A interview and exercise testing.

Adult↗