The Relevance of Ethnic Differences in Haemodynamic Responses to the Head-Up Tilt Manoeuvre to Clinical Pharmacological Investigations

Venter, C. P.; Joubert, P. H.; Strydom, W. J.

doi:10.1097/00005344-198509000-00032

Cited by 10 publications

(12 citation statements)

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“…The similar HR responses seen at presyncope extend those found using less severe orthostatic stressors [18,22,24,30] and reinforce those seen with pharmacologic stimuli [8,19]. Whites had a greater reduction in HR with propanolol [19] while blacks had a blunted HR response to isoproterenol [8].…”

Section: Discussionsupporting

confidence: 69%

“…Shvartz and colleagues [22] found whites to have a 5 mmHg decline in systolic blood pressure upon initial exposure to 70°head-up tilt while blood pressure did not change in blacks; the blood pressure responses did not differ from min 2 to 20 of headup tilt. Conversely, others found whites to have añ 7 mmHg increase in systolic blood pressure following 2 min of 80°head-up tilt while blood pressure did not change in blacks [30]. In both studies [22,30], HR did not differ significantly between the groups.…”

Section: Discussionmentioning

confidence: 72%

“…Conversely, others found whites to have añ 7 mmHg increase in systolic blood pressure following 2 min of 80°head-up tilt while blood pressure did not change in blacks [30]. In both studies [22,30], HR did not differ significantly between the groups. It is difficult to explain these disparate findings.…”

Section: Discussionmentioning

confidence: 72%

“…No study has directly assessed this hypothesis although older whites have a higher incidence of postural hypotension than similarly-aged blacks [25]. When compared to blacks, younger whites had mild depressor [22] or pressor [30] responses to brief head up tilt. Likewise, lower body negative pressure (LBNP) to -30 mmHg evoked similar responses between the two races [24], although others found LBNP to -40 mmHg resulted in blacks having greater increases in peripheral resistance per unit increase in sympathetic CAR 155 ■ Abstract This study tested the hypothesis that normotensive black males differ from white males in their autonomic and cardiovascular responses to severe orthostatic stress.…”

Section: Introductionmentioning

confidence: 99%

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Blacks and whites differ in responses, but not tolerance, to orthostatic stress

Franke

Lee

Buchanan

et al. 2004

Clinical Autonomic Research

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This study tested the hypothesis that normotensive black males differ from white males in their autonomic and cardiovascular responses to severe orthostatic stress. College age men (9 blacks, 9 whites) underwent graded lower body negative pressure (LBNP; 10 mmHg steps of 6 min each) to either -100 mmHg or presyncope. LBNP tolerance between the two groups did not differ (LBNP tolerance index: 378 +/- 34 vs 404 +/- 1 9mmHg.min, blacks vs whites). Responses to LBNP common to all subjects (< or = -40 mmHg), including spontaneous baroreflex sensitivity (sequence technique), did not differ between groups except whites experienced an earlier and more pronounced decline in total peripheral conductance than blacks (P < 0.01). At test termination, the heart rate variability measure of low frequency/high frequency ratio increased more in blacks than whites (5.2 +/- 1.1 vs 2.7 +/- 0.7 units; P < 0.05) while cardiac output and total peripheral conductance were lower in whites (both P < 0.05). These data suggest that blacks and whites have similar LBNP tolerances. They maintain blood pressure equally well when exposed to graded LBNP to presyncope, yet they differ in their mechanisms for doing so.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

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Blacks and whites differ in responses, but not tolerance, to orthostatic stress

Franke

Lee

Buchanan

et al. 2004

Clinical Autonomic Research

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“…Several experimental studies have suggested a differential response of blood pressure to standing due to ethnicity 3 and gender. 4,5 However, other studies found no gender differences.…”

mentioning

confidence: 99%

Descriptive Epidemiology of Blood Pressure Response to Change in Body Position

et al. 1999

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Abstract-The epidemiology of a common measure of cardiovascular reactivity, the change in systolic blood pressure (⌬SBP) from the supine to the standing position, is described in a cohort of 13 340 men and women aged 45 to 65 years enrolled in the Atherosclerosis Risk in Communities (ARIC) Study. The distribution of ⌬SBP was found to be symmetrical and unimodal, with a mean value near zero (Ϫ0.45 mm Hg). The range of ⌬SBP was from Ϫ63.2 to 54.3 mm Hg, and the standard deviation was 10.8. Stratification of ⌬SBP by race and gender shows a slight shift in distribution toward higher values for black men and women. ⌬SBP was categorized into deciles. Participants in the top 30% and bottom 30% of the distribution were compared with individuals in the middle 40% of the distribution, who had little or no change in SBP on standing. Participants in the bottom 30% (ie, SBP decreased on standing) were significantly older, had a greater prevalence of hypertension and peripheral vascular disease, had higher values of SBP, and had more cigarette-years of smoking. Among participants in the top 30% (ie, SBP increased on standing), a significantly larger proportion were black, mean seated SBP was higher, and the predicted risk of developing coronary heart disease after 8 years was greater. The response of SBP to change in posture showed considerable variability in a population sample of middle-aged adults. Cardiovascular morbidity, sociodemographic factors, and cigarette smoking were associated with the magnitude and direction of the postural change. (Hypertension. 1999;33:1123-1129.)Key Words: blood pressure Ⅲ cardiovascular reactivity Ⅲ epidemiology T he response of blood pressure to change in body position has been used in epidemiological studies as a measure of cardiovascular reactivity. Sparrow et al 1 reported that a 10-mm Hg or greater increase in diastolic blood pressure (DBP) from the supine to standing position significantly modified the effect of seated systolic blood pressure (SBP) and DBP on the incidence of myocardial infarction during 8.7 years of follow up in a cohort of middle-aged white men. On further investigation of this population, the investigators concluded that the difference between the supine and seated blood pressures is positively associated with subsequent development of systemic hypertension independent of supine blood pressure.The response of blood pressure to change in body position is well suited as a measure of cardiovascular reactivity for epidemiological studies. Several experimental studies have suggested a differential response of blood pressure to standing due to ethnicity 3 and gender. 4,5 However, other studies found no gender differences. 6,7 Little is known about the descriptive epidemiology of this measure of reactivity, especially among women and blacks. The purpose of this investigation was to focus on the descriptive epidemiology of the response of blood pressure to change in posture in a biracial, population-based sample, the Atherosclerosis Risk in Communities (ARIC) Study. Methods...

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Autonomic Reactivity and Hypertension in Blacks: Toward a Contextual Model

Anderson¹,

McNeilly²

1993

Pathophysiology of Hypertension in Blacks

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The Relevance of Ethnic Differences in Haemodynamic Responses to the Head-Up Tilt Manoeuvre to Clinical Pharmacological Investigations

Cited by 10 publications

References 0 publications

Blacks and whites differ in responses, but not tolerance, to orthostatic stress

Blacks and whites differ in responses, but not tolerance, to orthostatic stress

Descriptive Epidemiology of Blood Pressure Response to Change in Body Position

Autonomic Reactivity and Hypertension in Blacks: Toward a Contextual Model

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