Objectives: We sought to evaluate whether changes in resting baroreflex control of heart rate are a distinctive feature of healthy subjects with a history of syncope prone to a positive tilt-test response.
Background: The mechanisms involved in the pathogenesis of vasovagal syncope (VVS) are still poorly understood; in particular, the contribution of arterial baroreflex control of heart rate is matter of discussion.
Methods: A passive tilt-table test was performed in 312 consecutive, otherwise healthy subjects (age 36 +/- 15 years) with unexplained syncope and 100 control subjects. At baseline, spontaneous baroreflex sensitivity (BRS; ms/mm Hg) and the baroreflex effectiveness index (BEI) were assessed using the sequence method.
Results: The study population showed normal baroreflex function. Tilt-induced VVS in 94 subjects who were younger than both the tilt-negative and control subjects (30 +/- 14, 38 +/- 15, and 37 +/- 14 years, respectively; p = 0.00005) showed greater BRS (17.4 +/- 9.8, 13.2 +/- 7.9, and 12.8 +/- 8.2 ms/mm Hg, respectively; p = 0.0001), but had a similar BEI (0.59 +/- 0.18, 0.56 +/- 0.19, and 0.58 +/- 0.2, respectively; p = NS). On Cox multivariate analysis, the occurrence of VVS during tilt was inversely related to age (hazard ratio 0.97; p = 0.0004) and directly related to the BRS slope of sequences, implying a baroreceptor deactivation (hazard ratio 1.05; p = 0.02), but not of sequences characterized by arterial baroreceptor stimulation.
Conclusions: Subjects with tilt-induced VVS showed greater resting BRS but had a normal BEI. The enhanced reflex tachycardic response to arterial baroreceptor deactivation at rest may represent a characteristic feature of subjects prone to tilt-induced VVS.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/s0735-1097(03)00050-0 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Plethysmographic assessment of vasomotor response in patients with congestive heart failure before and after heart transplantation.
Biomed Opt Express
February 2024
Laboratory of New Functional Materials for Photonics, Institute of Automation and Control Processes of Far East Branch of the Russian Academy of Sciences, 690041 Vladivostok, Russia.
Sympathetic vasomotor response is the most important part of the autonomic regulation of circulation, which determines the quality of life. It is disrupted in a number of diseases, particularly in patients with congestive heart failure (CHF). However, experimental evaluation of reflex vasoconstriction is still a non-trivial task due to the limited set of available technologies.
View Article and Find Full Text PDFA single baroreceptor unit consists of multiple sensors.
Sci Rep
November 2021
Robley Rex VA Medical Center, Louisville, KY, 40206, USA.
Arterial baroreceptors (BRs) play a vital role in the regulation of the cardiopulmonary system. What is known about how these sensors operate at the subcellular level is limited, however. Until recently, one afferent axon was considered to be connected to a single baroreceptor (one-sensor theory).
View Article and Find Full Text PDFPhysiological Sympathetic Activation Reduces Systemic Inflammation: Role of Baroreflex and Chemoreflex.
Front Immunol
September 2021
Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
Baroreflex and chemoreflex act through the autonomic nervous system, which is involved with the neural regulation of inflammation. The present study reports the effects of reflex physiological sympathetic activation in endotoxemic rats using bilateral carotid occlusion (BCO), a physiological approach involving the baroreflex and chemoreflex mechanisms and the influence of the baroreceptors and peripheral chemoreceptors in the cardiovascular and systemic inflammatory responses. After lipopolysaccharide (LPS) administration, the arterial pressure was recorded during 360 min in unanesthetized rats, and serial blood samples were collected to analyze the plasma cytokine levels.
View Article and Find Full Text PDFAutonomic cardiovascular alterations as therapeutic targets in chronic kidney disease.
Clin Auton Res
August 2021
Clinica Medica, Department of Medicine and Surgery, University Milano-Bicocca, Milan, Italy.
Purpose: The present paper will review the impact of different therapeutic interventions on the autonomic dysfunction characterizing chronic renal failure.
Methods: We reviewed the results of the studies carried out in the last few years examining the effects of standard pharmacologic treatment, hemodialysis, kidney transplantation, renal nerve ablation and carotid baroreceptor stimulation on parasympathetic and sympathetic control of the cardiovascular system in patients with renal failure.
Results: Drugs acting on the renin-angiotensin system as well as central sympatholytic agents have been documented to improve autonomic cardiovascular control.
Selective denervation of the aortic and carotid baroreceptors in rats.
Exp Physiol
September 2019
Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
New Findings: What is the central question of this study? The traditional surgical approach for sino-aortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation, which does not permit their individual study in different situations. What is the main finding and its importance? We have described a new surgical approach capable of selective denervation of the arterial (aortic and carotid) baroreceptors, keeping the carotid bodies (chemoreceptors) intact. It is understood that this technique might be a useful tool for investigating the relative role of the baro- and chemoreceptors in several physiological and pathophysiological conditions.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!