Increased Baroreflex Sensitivity and Reduced Cardiovascular Reactivity in Individuals with Chronic Low Blood Pressure

Duschek, Stefan; Dietel, Anja; Schandry, Rainer; Paso, Gustavo A. Reyes del

doi:10.1291/hypres.31.1873

Cited by 39 publications

(48 citation statements)

References 34 publications

(45 reference statements)

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“…25 However, considering the rise in RSA, it seems likely that the reduction in LF power was not due to decreased parasympathetic influences but instead due to decreased sympathetic influences in the control of heart rate. Taken together, the findings suggest that the previously described increased BRS and dominance of the parasympathetic system in cardiac regulation of chronic hypotension 5,9,16 were further augmented by drug application. Midodrine does not cross the blood-brain barrier and, therefore, does not directly influence central nervous control of the cardiovascular system.…”

Section: Discussionsupporting

confidence: 64%

“…37,38 In chronic hypotension, the operating point of the baroreflex is believed to be reduced to lower blood pressure levels. 9 This study suggests that pharmacological blood pressure enhancement does not entail the resetting of the operating point to higher values, which could, for instance result from baroreceptor habituation. 38 Instead, the rise in BRS suggests that the attempt of the system to decrease blood pressure to low set points may even be strengthened by the application of an adrenergic drug.…”

Section: Discussionmentioning

confidence: 77%

“…The decrease in BRS attenuates the buffering effect of the reflex, thereby facilitating stress-induced blood pressure elevation. 9,39 These modulations in autonomic control may be regarded as adaptive mechanisms enabling the improvement of energetic and metabolic supply during acute stress. 40 Finally, the results may have clinical implications.…”

Section: Discussionmentioning

confidence: 99%

“…7 It has been considered whether alterations in autonomic cardiovascular regulation are involved in the etiology of chronic hypotension. 5,8 Duschek et al 9 reported increased baroreflex sensitivity (BRS) in a hypotensive sample. The baroreflex consists of a negative feedback loop in which changes in the firing rate of the arterial baroreceptors lead to compensatory alterations in heart rate and cardiac contractility.…”

Section: Introductionmentioning

confidence: 99%

“…15 While the operating point of the baroreflex is believed to be increased in individuals with elevated blood pressure, resetting to low blood pressure values may occur in persons with hypotension. 9 Besides aberrant baroreflex function, reduced sympathetic and increased parasympathetic influences on cardiovascular regulation have also been postulated in chronic hypotension. 5,16 Several studies have documented generally diminished sympathetic tone, 17,18 and Cadalbert 16 reported augmented respiratory sinus arrhythmia (RSA) in chronically hypotensive participants, indicating increased vagal influences on heart rate.…”

Section: Introductionmentioning

confidence: 99%

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Modulations of autonomic cardiovascular control following acute alpha-adrenergic treatment in chronic hypotension

Duschek¹,

Heiß²,

Werner³

et al. 2009

Hypertens Res

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Chronic low blood pressure is typically accompanied with symptoms such as fatigue, reduced drive, dizziness, headaches and cold limbs. Alterations in autonomic cardiovascular regulation are assumed to be involved in the etiology of this condition, that is, increased baroreflex sensitivity (BRS) as well as reduced sympathetic and augmented parasympathetic influences on cardiovascular regulation. In this study, the acute effects of the blood pressure-enhancing alpha-adrenergic agonist, midodrine, on autonomic cardiovascular control were investigated in 50 hypotensive persons (mean blood pressure 96/61 mm Hg) based on a placebo-controlled double blind design. BRS was determined using sequence analysis. Spectral analysis of heart rate variability was carried out to quantify sympathetic and parasympathetic cardiac control. Parameters were obtained at rest and during mental stress. Drug application led to marked increases in blood pressure, BRS and respiratory sinus arrhythmia (RSA), whereas heart rate and power in the low frequency (LF) band of the heart rate variability spectrum decreased. The augmentation of RSA and reduction of LF power indicate a shift of the sympathovagal balance toward increased parasympathetic and reduced sympathetic influences on heart rate. Like the increase in BRS, these modulations represent a counter-regulatory autonomic response to the blood pressure elevation, which is initiated to return blood pressure to the initial value or to an individual set point. The finding challenges the use of a-sympathomimetics in the treatment of chronic hypotension as they may not reduce but may instead exacerbate the autonomic dysbalance related to this condition.

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Section: Discussionsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modulations of autonomic cardiovascular control following acute alpha-adrenergic treatment in chronic hypotension

Duschek¹,

Heiß²,

Werner³

et al. 2009

Hypertens Res

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Cognitive performance in hypotensive persons with spinal cord injury

et al. 2009

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Background Due to sympathetic de-centralization, individuals with spinal cord injury (SCI), especially those with tetraplegia, often present with hypotension, worsened with upright posture. Several investigations in the non-SCI population have noted a relationship between chronic hypotension and deficits in memory, attention and processing speed and delayed reaction times. Objective To determine cognitive function in persons with SCI who were normotensive or hypotensive over a 24-h observation period while maintaining their routine activities. Methods Subjects included 20 individuals with chronic SCI (2–39 years), 13 with tetraplegia (C4–8) and 7 with paraplegia (T2–11). Individuals with hypotension were defined as having a mean 24-h systolic blood pressure (SBP) below 110 mmHg for males and 100 mmHg for females, and having spent ≥50% of the total time below these gender-specific thresholds. The cognitive battery used included assessment of memory (CVLT), attention and processing speed (Digit Span, Stroop word and color and Oral Trails A), language (COWAT) and executive function (Oral Trails B and Stroop color–word). Results Demographic parameters did not differ among the hypotensive and normotensive groups; the proportion of individuals with tetraplegia (82%) was higher in the hypotensive group. Memory was significantly impaired (P<0.05) and there was a trend toward slowed attention and processing speed (P<0.06) in the hypotensive compared to the normotensive group. Interpretation These preliminary data suggest that chronic hypotension in persons with SCI is associated with deficits in memory and possibly attention and processing speed, as previously reported in the non-SCI population.

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