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Anderson GK, Davis KA, Bhuiyan N, Rusy R, Rosenberg AJ, Rickards CA. The effect of oscillatory hemodynamics on the cardiovascular responses to simulated hemorrhage during isocapnia. J Appl Physiol (1985) 2023; 135:1312-1322. [PMID: 37881852 PMCID: PMC10911761 DOI: 10.1152/japplphysiol.00241.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
During cerebral hypoperfusion induced by lower body negative pressure (LBNP), cerebral tissue oxygenation is protected with oscillatory arterial pressure and cerebral blood flow at low frequencies (0.1 Hz and 0.05 Hz), despite no protection of cerebral blood flow or oxygen delivery. However, hypocapnia induced by LBNP contributes to cerebral blood flow reductions, and may mask potential protective effects of hemodynamic oscillations on cerebral blood flow. We hypothesized that under isocapnic conditions, forced oscillations of arterial pressure and blood flow at 0.1 Hz and 0.05 Hz would attenuate reductions in extra- and intracranial blood flow during simulated hemorrhage using LBNP. Eleven human participants underwent three LBNP profiles: a nonoscillatory condition (0 Hz) and two oscillatory conditions (0.1 Hz and 0.05 Hz). End-tidal (et) CO2 and etO2 were clamped at baseline values using dynamic end-tidal forcing. Cerebral tissue oxygenation (ScO2), internal carotid artery (ICA) blood flow, and middle cerebral artery velocity (MCAv) were measured. With clamped etCO2, neither ICA blood flow (ANOVA P = 0.93) nor MCAv (ANOVA P = 0.36) decreased with LBNP, and these responses did not differ between the three profiles (ICA blood flow: 0 Hz: 2.2 ± 5.4%, 0.1 Hz: -0.4 ± 6.6%, 0.05 Hz: 0.2 ± 4.8%; P = 0.56; MCAv: 0 Hz: -2.3 ± 7.8%, 0.1 Hz: -1.3 ± 6.1%, 0.05 Hz: -3.1 ± 5.0%; P = 0.87). Similarly, ScO2 did not decrease with LBNP (ANOVA P = 0.21) nor differ between the three profiles (0 Hz: -2.6 ± 3.3%, 0.1 Hz: -1.6 ± 1.5%, 0.05 Hz: -0.2 ± 2.8%; P = 0.13). Contrary to our hypothesis, cerebral blood flow and tissue oxygenation were protected during LBNP with isocapnia, regardless of whether hemodynamic oscillations were induced.NEW & NOTEWORTHY We examined the role of forcing oscillations in arterial pressure and blood flow at 0.1 Hz and 0.05 Hz on extra- and intracranial blood flow and cerebral tissue oxygenation during simulated hemorrhage (using lower body negative pressure, LBNP) under isocapnic conditions. Contrary to our hypothesis, both cerebral blood flow and cerebral tissue oxygenation were completely protected during simulated hemorrhage with isocapnia, regardless of whether oscillations in arterial pressure and cerebral blood flow were induced. These findings highlight the protective effect of preventing hypocapnia on cerebral blood flow under simulated hemorrhage conditions.
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Affiliation(s)
- Garen K Anderson
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - K Austin Davis
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Nasrul Bhuiyan
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Ryan Rusy
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Alexander J Rosenberg
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
- Physiology Department, Midwestern University, Downers Grove, Illinois, United States
- Integrative Physiology Laboratory, Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Li L, Zhao H, Ma X, Jiao F, Lin J. Calcitonin gene-related peptide predicts therapeutic response to midodrine hydrochloride in children with vasovagal syncope. Front Neurosci 2022; 16:1026539. [PMID: 36267231 PMCID: PMC9577468 DOI: 10.3389/fnins.2022.1026539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
The vasoconstriction agent midodrine hydrochloride is a vital treatment for pediatric patients diagnosed with vasovagal syncope (VVS), although the efficacy is variable. This study was designed to explore the value of calcitonin gene-related peptide (CGRP) in predicting the effect of midodrine hydrochloride treatment upon VVS patients. In total, 55 children diagnosed with VVS were treated with midodrine hydrochloride for 3 months. Therapeutic response was evaluated using a symptom score system. CGRP levels were significantly higher in VVS patients (68.700 ± 6.460) than in control subjects (43.400 ± 5.810; t = 18.207, P < 0.001) and symptom scores correlated positively with CGRP concentrations (r = 0.779, P < 0.001). Patients treated with midodrine hydrochloride showed a significant reduction in symptom scores [4 (0, 6.5) vs. 1 (1, 2); z = –6.481; P < 0.001]. However, the value of plasma CGRP were potently elevated in the positive-response subjects than in the negative-response subjects (70.080 ± 5.040) vs. (61.150 ± 3.090); t = 5.817; P < 0.001). The area under the ROC curve showed that the value of CGRP for predicting the therapeutic response to midodrine hydrochloride was 0.946 (95% CI: 0.879–0.997, P < 0.001). With high sensitivity (97.7%) and specificity (83.3%), CGRP predicted the therapeutic response to midodrine hydrochloride (cut-off value, 62.56 pg/ml). In conclusion, CGRP can be used to predict the effect of midodrine hydrochloride administration in VVS patients.
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Affiliation(s)
- Lintian Li
- School of Public Health, Xi’an Jiaotong University, Xi’an, China
| | - Huacai Zhao
- Department of Surgical, The Third Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Xiuxiu Ma
- School of Public Health, Xi’an Jiaotong University, Xi’an, China
| | - Fuyong Jiao
- Department of Pediatrics, The Third Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, China
| | - Jing Lin
- Key Laboratory for Disease Prevention and Control and Health Promotion of Shaanxi Province, Department of Child and Adolescent Health Science Center, Xi’an Jiaotong University, Xi’an, China
- *Correspondence: Jing Lin,
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Miranda CM, da Silva RMFL, Peruhybe-Magalhães V, Brugada J. Vasoactive Biomarkers in Patients With Vasovagal Syncope During Head-Up Tilt Test: A Case-Control Study. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2022; 16:11795468221116848. [PMID: 36046183 PMCID: PMC9421056 DOI: 10.1177/11795468221116848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 06/15/2022] [Indexed: 11/25/2022]
Abstract
Background: Vasovagal syncope (VVS) is the most common cause of syncope. Some stages of its pathophysiological mechanisms remain unclear. Vasoactive substances such as nitric oxide metabolites (NOx) and endothelin (ET) may be involved during acute orthostatic stress. Objective: To analyze plasma changes in NOx and ET and heart rate variability (HRV) in the supine positions (T1) and during the head-up tilt test (HUTT) (T2), in patients with VVS (case group) and control group. Methods: Thirty-seven patients (17 in the case group and 20 in the control group), matched for age and sex (mean aged 31.8 years) underwent HUTT with simultaneous HRV recording and venipuncture. Blood samples were collected during phases T1 and T2 and the analysis was performed without knowledge of the HUTT result. Results: In the total sample, there was an increase in NOx values (P = .014), however there was no increase in ET values from phase T1 to phase T2. Patients with VVS tended to increase plasma NOx values (P = .057) and had significantly higher plasma values compared to ET (P = .033) between phases T1 to T2. In the control group, there was no significant change in the values of these vasoactive substances. Regarding HRV, there were a decrease in the component HF (high frequency) and increased of the LF (low frequency)/HF ratio during HUTT. Conclusions: There was an increase in ET during HUTT occurred only in the case group. These patients are more likely to have an imbalance between antagonistic vasoactive biomarkers during orthostatic stress.
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Affiliation(s)
- Cláudia Madeira Miranda
- Faculty of Medicine, Federal University of Minas Gerais, Brazil.,Madre Teresa Hospital, Minas Gerais, Brazil
| | | | | | - Josep Brugada
- Institut Clínic Cardiovascular, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
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LAZUROVA Z, HABALOVA V, MITRO P. Association of Polymorphisms in Endothelin-1 and Endothelin Receptor A Genes With Vasovagal Syncope. Physiol Res 2022; 71:93-101. [DOI: 10.33549/physiolres.934689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The endothelin system may play a role in the pathogenesis of vasovagal syncope (VVS) because it is implicated in blood pressure regulation. We hypothesized that endothelin-related genetic polymorphisms might modulate susceptibility to VVS. This study aimed to evaluate the possible influence of endothelin-1 (EDN1) and endothelin receptor A (EDNRA) gene variants on the occurrence of tilt-induced VVS and autonomic nervous system activity during the head-up tilt test (HUT). Results were expressed as mean ± SEM. In 254 patients with recurrent syncope (age 45.33±1.22 years, 94 males, 160 females), heart rate variability (HRV) was measured during HUT. EDN1 rs5370 G>T and EDNRA rs5333 T>C gene polymorphisms were assessed using high-resolution melting analysis. There was no statistically significant association between polymorphisms EDN1 rs5370 and EDNRA rs5333 and positivity of HUT or hemodynamic types of VVS. Patients with GT or TT genotypes at the rs5370 locus of the EDN1 had significantly higher values of high-frequency (HF) and the standard deviation of the average NN intervals at the time of the syncope, and they tended to have lower low-frequency (LF) and LF/HF ratio when compared to homozygotes (GG). No statistically significant differences were found in HRV parameters concerning the EDNRA rs5333 genotypes. Our findings suggest the potential role of EDN1 rs5370 variants in regulating autonomic nervous activity and pathogenesis of VVS.
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Affiliation(s)
- Z LAZUROVA
- Fourth Department of Internal Medicine, Medical Faculty of University of P.J. Safarik, Kosice, Slovak, Republic
| | - V HABALOVA
- Department of Medical Biology, Medical Faculty of University of P.J. Safarik, Kosice, Slovak Republic
| | - P MITRO
- First Department of Cardiology, Medical Faculty of University of P.J. Safarik, Kosice, Slovak Republic
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Reid MB. Redox Implications of Extreme Task Performance: The Case in Driver Athletes. Cells 2022; 11:cells11050899. [PMID: 35269521 PMCID: PMC8909750 DOI: 10.3390/cells11050899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 02/04/2023] Open
Abstract
Redox homeostasis and redox-mediated signaling mechanisms are fundamental elements of human biology. Physiological levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) modulate a range of functional processes at the cellular, tissue, and systemic levels in healthy humans. Conversely, excess ROS or RNS activity can disrupt function, impairing the performance of daily activities. This article analyzes the impact of redox mechanisms on extreme task performance. Such activities (a) require complex motor skills, (b) are physically demanding, (c) are performed in an extreme environment, (d) require high-level executive function, and (e) pose an imminent risk of injury or death. The current analysis utilizes race car driving as a representative example. The physiological challenges of this extreme task include physical exertion, g loading, vibration, heat exposure, dehydration, noise, mental demands, and emotional factors. Each of these challenges stimulates ROS signaling, RNS signaling, or both, alters redox homeostasis, and exerts pro-oxidant effects at either the tissue or systemic levels. These redox mechanisms appear to promote physiological stress during race car driving and impair the performance of driver athletes.
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Affiliation(s)
- Michael B Reid
- College of Health and Human Performance, University of Florida, Gainesville, FL 32611, USA
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Clinical and neuroendocrinological characteristics of delayed orthostatic hypotension in Parkinson's disease. Clin Auton Res 2021; 31:425-431. [PMID: 33496860 DOI: 10.1007/s10286-020-00758-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/14/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE Delayed orthostatic hypotension (DOH), a fall in blood pressure after a 3-min cutoff, is clinically meaningful. The aim of this study was to elucidate the clinical and neuroendocrinological characteristics of DOH in patients with Parkinson's disease (PD). METHODS A total of 132 patients with newly diagnosed PD were enrolled. Baseline clinical characteristics, including olfactory function, and changes in norepinephrine (NE) and vasopressin (ADH) concentrations during the head-up tilt test (HUT), were examined. RESULTS Fifty-five patients (42%) had classical orthostatic hypotension (COH), and 19 patients (14%) had DOH. Patients with COH and DOH tended to have more severe hyposmia than patients without OH. A multivariate linear regression model showed that hyposmia was associated with DOH and COH. The increase of heart rate against the fall in blood pressure was significantly lower in patients with COH and DOH than those without OH. The NE levels at supine rest and after upright tilting were lower in the COH group than in the PD without OH and DOH groups. The levels of ADH were higher in the DOH group than in the COH group at supine rest and higher than in the PD without OH group after upright tilting. There was no significant difference in the cardiac 123I-MIBG scintigraphy between the COH and DOH groups. CONCLUSION Compared with patients without OH, patients with DOH had severe hyposmia. Relatively preserved peripheral sympathetic nervous system function in patients with DOH suggests that DOH might be an early and milder form of OH in PD.
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Benditt DG, van Dijk JG, Krishnappa D, Adkisson WO, Sakaguchi S. Neurohormones in the Pathophysiology of Vasovagal Syncope in Adults. Front Cardiovasc Med 2020; 7:76. [PMID: 32478097 PMCID: PMC7232538 DOI: 10.3389/fcvm.2020.00076] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/14/2020] [Indexed: 02/02/2023] Open
Abstract
Vasovagal syncope (VVS) is the most common cause of syncope across all age groups. Nonetheless, despite its clinical importance and considerable research effort over many years, the pathophysiology of VVS remains incompletely understood. In this regard, numerous studies have been undertaken in an attempt to improve insight into the evolution of VVS episodes and many of these studies have examined neurohormonal changes that occur during the progression of VVS events primarily using the head-up tilt table testing model. In this regard, the most consistent finding is a marked increase in epinephrine (Epi) spillover into the circulation beginning at an early stage as VVS evolves. Reported alterations of circulating norepinephrine (NE), on the other hand, have been more variable. Plasma concentrations of other vasoactive agents have been reported to exhibit more variable changes during a VVS event, and for the most part change somewhat later, but in some instances the changes are quite marked. The neurohormones that have drawn the most attention include arginine vasopressin [AVP], adrenomedullin, to a lesser extent brain and atrial natriuretic peptides (BNP, ANP), opioids, endothelin-1 (ET-1) and serotonin. However, whether some or all of these diverse agents contribute directly to VVS pathophysiology or are principally a compensatory response to an evolving hemodynamic crisis is as yet uncertain. The goal of this communication is to summarize key reported neurohumoral findings in VVS, and endeavor to ascertain how they may contribute to observed hemodynamic alterations during VVS.
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Affiliation(s)
- David G Benditt
- Cardiovascular Division, Department of Medicine, Cardiac Arrhythmia and Syncope Center, University of Minnesota Medical School, Minneapolis, MN, United States
| | - J Gert van Dijk
- Department of Neurology, Leiden University Medical Center, Leiden, Netherlands
| | - Darshan Krishnappa
- Cardiovascular Division, Department of Medicine, Cardiac Arrhythmia and Syncope Center, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Wayne O Adkisson
- Cardiovascular Division, Department of Medicine, Cardiac Arrhythmia and Syncope Center, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Scott Sakaguchi
- Cardiovascular Division, Department of Medicine, Cardiac Arrhythmia and Syncope Center, University of Minnesota Medical School, Minneapolis, MN, United States
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Engelland RE, Hemingway HW, Tomasco OG, Olivencia-Yurvati AH, Romero SA. Neural control of blood pressure is altered following isolated leg heating in aged humans. Am J Physiol Heart Circ Physiol 2020; 318:H976-H984. [PMID: 32142377 DOI: 10.1152/ajpheart.00019.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is a sustained reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating. We tested the hypothesis that acute leg heating would decrease arterial blood pressure in aged adults secondary to sympathoinhibition. We exposed 13 young and 10 aged adults to 45 min of leg heating. Muscle sympathetic nerve activity (radial nerve) was measured before leg heating (preheat) and 30 min after (recovery) and is expressed as burst frequency. Neurovascular transduction was examined by assessing the slope of the relation between muscle sympathetic nerve activity and leg vascular conductance measured at rest and during isometric handgrip exercise performed to fatigue. Arterial blood pressure was well maintained in young adults (preheat, 86 ± 6 mmHg vs. recovery, 88 ± 7 mmHg; P = 0.4) due to increased sympathetic nerve activity (preheat, 16 ± 7 bursts/min vs. recovery, 22 ± 10 bursts/min; P < 0.01). However, in aged adults, sympathetic nerve activity did not differ from preheat (37 ± 5 bursts/min) to recovery (33 ± 6 bursts/min, P = 0.1), despite a marked reduction in arterial blood pressure (preheat, 101 ± 7 mmHg vs. recovery, 94 ± 6 mmHg; P < 0.01). Neurovascular transduction did not differ from preheat to recovery for either age group (P ≥ 0.1). The reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating is mediated, in part, by a sympathoinhibitory effect that alters the compensatory neural response to hypotension.NEW & NOTEWORTHY There is a sustained reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating. However, the neurovascular mechanisms mediating this response remain unknown. Our findings demonstrate for the first time that this reduction in arterial blood pressure is mediated, in part, by a sympathoinhibitory effect that alters the compensatory neural response to hypotension in aged adults.
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Affiliation(s)
- Rachel E Engelland
- Department of Physiology and Anatomy, Human Vascular Physiology Laboratory, University of North Texas Health Science Center, Ft. Worth, Texas
| | - Holden W Hemingway
- Department of Physiology and Anatomy, Human Vascular Physiology Laboratory, University of North Texas Health Science Center, Ft. Worth, Texas
| | - Olivia G Tomasco
- Department of Physiology and Anatomy, Human Vascular Physiology Laboratory, University of North Texas Health Science Center, Ft. Worth, Texas
| | - Albert H Olivencia-Yurvati
- Department of Physiology and Anatomy, Human Vascular Physiology Laboratory, University of North Texas Health Science Center, Ft. Worth, Texas.,Department of Surgery, University of North Texas Health Science Center, Ft. Worth, Texas
| | - Steven A Romero
- Department of Physiology and Anatomy, Human Vascular Physiology Laboratory, University of North Texas Health Science Center, Ft. Worth, Texas
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Torabi P, Ricci F, Hamrefors V, Sutton R, Fedorowski A. Classical and Delayed Orthostatic Hypotension in Patients With Unexplained Syncope and Severe Orthostatic Intolerance. Front Cardiovasc Med 2020; 7:21. [PMID: 32154270 PMCID: PMC7046587 DOI: 10.3389/fcvm.2020.00021] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 02/05/2020] [Indexed: 11/30/2022] Open
Abstract
Background: Orthostatic hypotension (OH) is a major sign of cardiovascular autonomic failure leading to orthostatic intolerance and syncope. Orthostatic hypotension is traditionally divided into classical OH (cOH) and delayed OH (dOH), but the differences between the two variants are not well-studied. We performed a systematic clinical and neuroendocrine characterization of OH patients in a tertiary syncope unit. Methods: Among 2,167 consecutive patients (1,316 women, 60.7%; age, 52.6 ± 21.0 years) evaluated for unexplained syncope and severe orthostatic intolerance with standardized cardiovascular autonomic tests including head-up tilt (HUT), we identified those with a definitive diagnosis of cOH and dOH. We analyzed patients' history, clinical characteristics, hemodynamic variables, and plasma levels of epinephrine, norepinephrine, C-terminal-pro-arginine-vasopressin (CT-proAVP), C-terminal-endothelin-1, mid-regional-fragment of pro-atrial-natriuretic-peptide and pro-adrenomedullin in the supine position and at 3-min HUT. Results: We identified 248 cOH and 336 dOH patients (27% of the entire cohort); 111 cOH and 152 dOH had blood samples collected in the supine position and at 3-min HUT. Compared with dOH, cOH patients were older (68 vs. 60 years, p < 0.001), more often male (56.9 vs. 39.6%, p < 0.001), had higher systolic blood pressure (141 vs. 137 mmHg, p = 0.05), had lower estimated glomerular filtration rate (73 vs. 80 ml/min/1.73 m2, p = 0.003), more often pathologic Valsalva maneuver (86 vs. 49 patients, p < 0.001), pacemaker-treated arrhythmia (5 vs. 2%, p = 0.04), Parkinson's disease (5 vs. 1%, p = 0.008) and reported less palpitations before syncope (16 vs. 29%, p = 0.001). Supine and standing levels of CT-proAVP were higher in cOH (p = 0.022 and p < 0.001, respectively), whereas standing norepinephrine was higher in dOH (p = 0.001). After 3-min HUT, increases in epinephrine (p < 0.001) and CT-proAVP (p = 0.001) were greater in cOH, whereas norepinephrine increased more in dOH (p = 0.045). Conclusions: One-quarter of patients with unexplained syncope and severe orthostatic intolerance present orthostatic hypotension. Classical OH patients are older, more often have supine hypertension, pathologic Valsalva maneuver, Parkinson's disease, pacemaker-treated arrhythmia, and lower glomerular filtration rate. Classical OH is associated with increased vasopressin and epinephrine during HUT, but blunted increase in norepinephrine.
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Affiliation(s)
- Parisa Torabi
- Department of Clinical Sciences, Faculty of Medicine, Clinical Research Center, Lund University, Malmö, Sweden.,Department of Clinical Physiology, Skåne University Hospital, Malmö, Sweden
| | - Fabrizio Ricci
- Department of Clinical Sciences, Faculty of Medicine, Clinical Research Center, Lund University, Malmö, Sweden.,Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. D'Annunzio" University, Chieti, Italy
| | - Viktor Hamrefors
- Department of Clinical Sciences, Faculty of Medicine, Clinical Research Center, Lund University, Malmö, Sweden.,Department of Internal Medicine, Skåne University Hospital, Malmö, Sweden
| | - Richard Sutton
- Department of Clinical Sciences, Faculty of Medicine, Clinical Research Center, Lund University, Malmö, Sweden.,National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Artur Fedorowski
- Department of Clinical Sciences, Faculty of Medicine, Clinical Research Center, Lund University, Malmö, Sweden.,Department of Cardiology, Skåne University Hospital, Malmö, Sweden
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10
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Abstract
See Article Torabi et al
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Affiliation(s)
- Noah N Williford
- 1 University of Iowa Hospitals & Clinics the Veterans Affairs Medical Center Iowa City IA
| | - Mark W Chapleau
- 1 University of Iowa Hospitals & Clinics the Veterans Affairs Medical Center Iowa City IA
| | - Brian Olshansky
- 1 University of Iowa Hospitals & Clinics the Veterans Affairs Medical Center Iowa City IA
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Chidambaram S, Goh EL, Rey VG, Khan MA. Vasopressin vs noradrenaline: Have we found the perfect recipe to improve outcome in septic shock? J Crit Care 2018; 49:99-104. [PMID: 30415181 DOI: 10.1016/j.jcrc.2018.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 10/04/2018] [Accepted: 10/29/2018] [Indexed: 11/28/2022]
Abstract
PURPOSE The metabolic and circulatory disturbances in patients with septic shock results in a high mortality rate. There is a lack of high-level evidence on the optimal approach. We present a meta-analysis elucidating the outcomes of regimes with only noradrenaline versus a combination of noradrenaline and vasopressin in managing septic shock. METHODS A literature search of studies comparing the use of noradrenaline and vasopressin in septic shock was conducted, using MEDLINE and EMBASE databases. The primary outcome evaluated was mortality rate. Subgroup analysis of secondary measures was also conducted using Review Manager 5.3 software. RESULTS Four RCTs of 1039 patients were included. There is good evidence supporting a comparable mortality rate (RR: 0.92, 95% CI: 0.78, 1.08, p = .32, I2 = 0%), and moderate evidence supporting an equivalent length of ICU stay (MD: 0.14, 95% CI: -1.37, 1.65, p = .86, I2 = 46%) and occurrence of adverse events (RR: 1.19, 95% CI: 0.83, 1.70, p = .35, I2 = 13%) between the two cohorts. CONCLUSION The two regimes have equivalent outcomes, but vasopressin has a role in selected patients experiencing less severe septic shock beyond a 36-h period. Further work will make definitive clinical recommendations for optimal strategy of vasopressin or noradrenaline usage.
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Affiliation(s)
- Swathikan Chidambaram
- Faculty of Medicine, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - En Lin Goh
- Faculty of Medicine, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Vanessa Garnelo Rey
- Department of Critical Care, Imperial College London, St Mary's Hospital, W2 1NY, London, United Kingdom
| | - Mansoor Ali Khan
- Department of Surgery and Trauma, Imperial College London, St Mary's Hospital, W2 1NY London, United Kingdom.
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Rash A, McRae M, Fatehi J, Richie D, Solbiati M, Pillay N, Ulke-Lemée A, MacDonald J, Sheldon R. Assessment of endothelin and copeptin as biomarkers for vasovagal syncope. Eur J Clin Invest 2016; 46:141-5. [PMID: 26641207 DOI: 10.1111/eci.12576] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/26/2015] [Indexed: 01/13/2023]
Abstract
BACKGROUND The diagnosis of vasovagal syncope continues to be difficult despite the use of accurate histories, tilt testing and implantable loop recorders. A circulating biomarker might be useful to facilitate diagnoses. Both endothelin-1 and vasopressin are increased during positive tilt tests resulting in syncope. Copeptin is a stable cleavage product of vasopressin formation. We conducted a pilot study to assess the utility of endothelin-1 and copeptin as circulating biomarkers of vasovagal syncope. METHODS Three populations were studied: syncope patients, epilepsy patients and controls. Vasovagal syncope diagnosis was ascertained with the Calgary Syncope Score and epilepsy diagnosis was confirmed with EEG. Plasma levels of endothelin-1 were measured using by ELISA and copeptin levels were determined using an EIA kit. RESULTS Asymptomatic control subjects had mean age 35 ± 11 years (7/22 male); epileptic subjects had mean age 32 ± 7 years (4/15 male); and syncope subjects had mean age 33 ± 16 years (4 of 21 male). Circulating plasma levels of endothelin-1 and copeptin were no different among the three groups. Mean concentrations of endothelin-1 were as follows: syncope, 23 ± 32 pg/mL; controls, 21 ± 17 pg/mL; and epileptics, 18 ± 12 pg/mL. Mean concentrations of copeptin were as follows: syncope, 1·29 ± 0·79 ng/mL; controls, 1·25 ± 0·79 ng/mL; and seizures, 1·23 ± 0·45 ng/mL. There were no significant correlations between syncope frequency and copeptin or endothelin-1 levels. CONCLUSION Circulating plasma endothelin-1 and copeptin levels are not significantly different among populations of controls, syncope patients and seizure patients.
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Affiliation(s)
- Arjun Rash
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Maureen McRae
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Jaleh Fatehi
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Deborah Richie
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Monica Solbiati
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Neelan Pillay
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Annegret Ulke-Lemée
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Justin MacDonald
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
| | - Robert Sheldon
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada
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Tijero B, Gabilondo I, Lezcano E, Teran-Villagrá N, Llorens V, Ruiz-Martinez J, Marti-Masso JF, Carmona M, Luquin MR, Berganzo K, Fernandez I, Fernandez M, Zarranz JJ, Gómez-Esteban JC. Autonomic involvement in Parkinsonian carriers of PARK2 gene mutations. Parkinsonism Relat Disord 2015; 21:717-22. [DOI: 10.1016/j.parkreldis.2015.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 04/03/2015] [Accepted: 04/14/2015] [Indexed: 12/19/2022]
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Orthostatic Changes in Hemodynamics and Cardiovascular Biomarkers in Dysautonomic Patients. PLoS One 2015; 10:e0128962. [PMID: 26053073 PMCID: PMC4460014 DOI: 10.1371/journal.pone.0128962] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 05/04/2015] [Indexed: 01/24/2023] Open
Abstract
Background Impaired autonomic control of postural homeostasis results in orthostatic intolerance. However, the role of neurohormones in orthostatic intolerance has not been explained. Methods Six-hundred-and-seventy-one patients (299 males; 55±22 years) with unexplained syncope underwent head-up tilt (HUT) with serial blood sampling. Systolic blood pressure (SBP) and heart rate (HR) supine, after 3min, and lowest BP/highest HR during HUT were recorded. Plasma levels of epinephrine, norepinephrine, renin, C-terminal-pro-arginine-vasopressin (CT-proAVP), C-terminal- endothelin-1 (CT-proET-1), and mid-regional-fragment of pro-atrial-natriuretic-peptide (MR-proANP) were determined at supine and 3min of HUT. Multivariate-adjusted logistic regression model was applied to compare 1st (reference) with 4th quartile of 3 min and maximal ΔSBP/ΔHR (i.e. pronounced hypotension or tachycardia) vs. changes in neuroendocrine biomarkers, respectively. Results Higher resting CT-proET-1 predicted BP fall at 3min (Odds ratio (OR) per 1 SD: 1.62, 95%CI 1.18–2.22; p = 0.003), and max BP fall during HUT (1.82, 1.28–2.61; p = 0.001). Higher resting CT-proAVP predicted BP fall at 3min (1.33, 1.03–1.73; p = 0.03), which was also associated with increase in CT-proAVP (1.86, 1.38–2.51; p = 0.00005) and epinephrine (1.47, 1.12–1.92; p = 0.05) during HUT. Lower resting MR-proANP predicted tachycardia at 3min (0.37, 0.24–0.59; p = 0.00003), and max tachycardia during HUT (0.47, 0.29–0.77; p = 0.002). Further, tachycardia during HUT was associated with increase in epinephrine (1.60, 1.15–2.21; p = 0.005), and norepinephrine (1.87, 1.38–2.53; p = 0.005). Conclusions Resting CT-proET-1 and CT-proAVP are increased in orthostatic hypotension, while resting MR-proANP is decreased in postural tachycardia. Moreover, early BP fall during orthostasis evokes increase in CT-proAVP and epinephrine, while postural tachycardia is associated with increase in norepinephrine and epinephrine.
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Fedorowski A, Burri P, Struck J, Juul-Möller S, Melander O. Novel cardiovascular biomarkers in unexplained syncopal attacks: the SYSTEMA cohort. J Intern Med 2013; 273:359-67. [PMID: 23510366 DOI: 10.1111/joim.12043] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of the study was to investigate the resting levels of novel cardiovascular biomarkers in common types of noncardiac syncope. DESIGN AND SETTING An observational study was conducted including 255 patients (mean age 60 years, range 15-93; 45% men) with unexplained syncopal attacks. Subjects underwent an expanded head-up tilt test including carotid sinus massage, and nitroglycerin provocation if indicated. Using logistic regression, we explored the associations between specific diagnoses of syncope and resting levels of circulating biomarkers: C-terminal pro-arginine vasopressin (CT-proAVP), C-terminal endothelin-1 precursor fragment (CT-proET-1), midregional fragments of pro-atrial natriuretic peptide (MR-proANP) and pro-adrenomedullin (MR-proADM). RESULTS A total of 142 (56%) patients were diagnosed with vasovagal syncope (VVS), 85 (33%) with orthostatic hypotension (OH) and 47 (18%) with carotid sinus hypersensitivity (CSH); in addition, 74 (29%) patients had more than one diagnosis. Thirty-five patients (14%) demonstrated a cardioinhibitory reflex. The probability of VVS was highest in the first quartile of MR-proANP [Q1 vs. Q4: odds ratio (OR) 5.57, 95% confidence interval (CI) 1.86-16.74; P < 0.001] and CT-proET-1 (OR 7.17, 95% CI 2.43-21.13; P < 0.001). By contrast, the probability of OH was highest in the fourth quartile of CT-proET-1 (Q4 vs. Q1: OR 8.66, 95% CI 2.49-30.17; P < 0.001). Furthermore, CSH was most frequently observed in the first quartile of MR-proANP (Q1 vs. Q4: OR 6.57, 95% CI 1.62-26.62; P = 0.008) among those over 60 years of age, whereas the cardioinhibitory reflex was strongly associated with low CT-proET-1 levels (Q1 vs. Q4: OR 69.7, 95% CI 6.97-696.6; P < 0.001). Moreover, in patients with VVS, a high concentration of CT-proET-1 was predictive of OH (OR per 1 SD 2.4, 95% CI 1.15-5.02; P = 0.02), whereas low CT-proET-1 suggested involvement of the cardioinhibitory reflex (OR per 1SD 0.42, 95% CI 0.25-0.70; P = 0.001). CONCLUSIONS The levels of MR-proANP and CT-proET-1 are markedly changed in common forms of syncope, suggesting the involvement of novel neurohormonal mechanisms in syncopal attacks.
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Affiliation(s)
- A Fedorowski
- Department of Clinical Sciences, Lund University, Clinical Research Center, Malmö, Sweden.
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Fan XH, Wang H, Gao LG, Sun K, Zhou XL, Hui RT. The association of an adenine insertion variant in the 5'UTR of the endothelin-1 gene with hypertension and orthostatic hypotension. Arch Med Sci 2012; 8:219-26. [PMID: 22661993 PMCID: PMC3361033 DOI: 10.5114/aoms.2012.28548] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 11/14/2011] [Accepted: 01/07/2012] [Indexed: 01/11/2023] Open
Abstract
INTRODUCTION An adenine insertion polymorphism in the 5' untranslated region of the endothelin-1 gene is functional and increases the expression of endothelin mRNA and protein in the insertion homozygote. In the present study we hypothesized that this functional polymorphism might be associated with hypertension and/or orthostatic hypotension. MATERIAL AND METHODS The adenine insertion polymorphism was genotyped in 381 untreated hypertensive patients and 298 normotensive subjects, all of whom underwent an upright posture study for orthostatic blood pressure measurements. Orthostatic hypotension was defined as a drop in blood pressure of 20/10 mm Hg or more within 3 min of assuming the upright posture. RESULTS The allele frequency of the adenine insertion was similar in hypertensive and normotensive subjects (15.2% vs. 15.3%, p > 0.05). After adjustment for age, sex and body mass index, blood pressure levels did not differ significantly among the genotypes in both hypertensives and normotensives. No associations were found between the distribution of the adenine insertion genotypes and the risk of orthostatic hypotension in both hypertensive patients and normotensive subjects even after adjustment for demographic parameters and supine systolic or diastolic blood pressure. Neither hypertensive nor normotensive subjects showed significant differences in orthostatic systolic or diastolic blood pressure changes among the genotype groups (all p > 0.05). CONCLUSIONS We concluded that the functional adenine insertion polymorphism in the endothelin-1 gene is not associated with either hypertension or orthostatic hypotension risk in Chinese.
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Affiliation(s)
- Xiao-han Fan
- Department of Cardiology, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hu Wang
- Sino-German Laboratory for Molecular Medicine and Key Laboratory for Clinical Cardiovascular Genetics, Ministry of Education, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ling-gen Gao
- Department of Cardiology, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kai Sun
- Sino-German Laboratory for Molecular Medicine and Key Laboratory for Clinical Cardiovascular Genetics, Ministry of Education, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiang-liang Zhou
- Department of Cardiology, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ru-tai Hui
- Department of Cardiology, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Sino-German Laboratory for Molecular Medicine and Key Laboratory for Clinical Cardiovascular Genetics, Ministry of Education, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Abstract
Needle phobia has profound health, dental, societal, and legal implications, and severe psychological, social, and physiologic consequences. There is genetic evidence for the physiologic response to needle puncture, and a significant familial psychological component, showing evidence of inheritance. Needle phobia is also a learned behavior. The dental practitioner must recognize patients with needle phobia before the administration of local anesthetics to identify patients who are potentially reactive and to prevent untoward sequelae. Needle phobia is highly associated with avoidance behavior, and the dentist must exhibit compassion and respect. To avoid bradycardia, hypotension, unconsciousness, convulsions, and possibly asystole, oral premedication with benzodiazepines or other antianxiety agents must be considered for patients who are needle phobic. Management of needle phobiaeinduced syncope includes perioperative monitoring, oxygen administration, positioning, atropine, and vasopressors.
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Schiffrin EL. How Are Stressed Prehypertensive Rats Pressured? Hypertension 2010; 56:191-2. [DOI: 10.1161/hypertensionaha.110.154013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ernesto L. Schiffrin
- From the Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
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Endothelin system polymorphisms in tilt test-induced vasovagal syncope. Clin Auton Res 2009; 19:347-54. [DOI: 10.1007/s10286-009-0008-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 01/14/2009] [Indexed: 10/20/2022]
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Endothelin system polymorphisms in tilt test-induced vasovagal syncope. Clin Auton Res 2009; 19:123-9. [DOI: 10.1007/s10286-009-0519-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 01/14/2009] [Indexed: 10/21/2022]
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White M, Rouleau JL, Afzal R, Floras J, Yusuf S, McKelvie RS. Effects of enalapril, candesartan or both on neurohumoral activation and LV volumes and function in patients with heart failure not treated with a beta-blocker. Ther Adv Cardiovasc Dis 2009; 3:113-21. [DOI: 10.1177/1753944708103658] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background: The long-term effects of the angiotensin-receptor blocker candesartan, the angiotensin-converting enzyme inhibitor enalapril or their combination have been incompletely studied in a large cohort of patients with heart failure not treated with beta-blockers. The objective of this study was to investigate the changes in neurohormones and LV volumes and ejection fraction in patients treated with enalapril, candesartan, or enalapril plus candesartan without concomitant beta-blocker therapy. Methods: Three hundred and ninety-two patients from the RESOLVD pilot study not treated with a beta-blocker at baseline or at any time during the trial were analyzed. Norepinephrine, endothelin-1, big endothelin-1, angiotensin-II, aldosterone, N-terminal proANP, BNP, and radionuclide angiography were measured before and after 43 weeks of treatment with candesartan alone ( n = 162), or enalapril alone ( n = 45), or candesartan plus enalapril ( n = 185). Endpoints were assessed at baseline and after 43 weeks of therapy. Results: LV end-diastolic and end-systolic volumes increased significantly at 43 weeks in all groups except for patients treated with enalapril plus candesartan. BNP decreased at 43 weeks only in patients receiving dual angiotensin-II suppression (-6.1 ± 37.8 pmol/l). Angiotensin-II levels were significantly increased in patients treated with candesartan (+23.6 ± 47.1 pg/ml; p<0.05). Conclusion: We conclude that angiotensin-II modulation, with enalapril and candesartan, without concomitant utilization of beta-blocker lead to a decrease in BNP and an attenuation of the increase in LV end-diastolic and end-systolic volumes without a reversal of this process in the long term.
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Affiliation(s)
- Michel White
- Research Center, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada,
| | - Jean-Lucien Rouleau
- Research Center, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
| | - Rizwan Afzal
- Department of Medicine, McMaster Hospital, Hamilton, Ontario, Canada
| | - John Floras
- Division of Cardiology, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Salim Yusuf
- Department of Medicine, McMaster Hospital, Hamilton, Ontario, Canada
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Freeman R, Kaufmann H. DISORDERS OF ORTHOSTATIC TOLERANCE-ORTHOSTATIC HYPOTENSION, POSTURAL TACHYCARDIA SYNDROME, AND SYNCOPE. Continuum (Minneap Minn) 2007. [DOI: 10.1212/01.con.0000299966.05395.6c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Fischer D, Arbeille P, Shoemaker JK, O'Leary DD, Hughson RL. Altered hormonal regulation and blood flow distribution with cardiovascular deconditioning after short-duration head down bed rest. J Appl Physiol (1985) 2007; 103:2018-25. [PMID: 17872408 DOI: 10.1152/japplphysiol.00121.2007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study tested the hypothesis that cardiovascular and hormonal responses to lower body negative pressure (LBNP) would be altered by 4-h head down bed rest (HDBR) in 11 healthy young men. In post-HDBR testing, three subjects failed to finish the protocol due to presyncopal symptoms, heart rate was increased during LBNP compared with pre-HDBR, mean arterial blood pressure was elevated at 0, −10, and −20 mmHg and reduced at −40 mmHg, central venous pressure (CVP) and cardiac stroke volume were reduced at all levels of LBNP. Plasma concentrations of renin, angiotensin II, and aldosterone were significantly lower after HDBR. Renin and angiotensin II increased in response to LBNP only post-HDBR. There was no effect of HDBR or LBNP on norepinephrine while epinephrine tended to increase at −40 mmHg post-HDBR ( P = 0.07). Total blood volume was not significantly reduced. Splanchnic blood flow taken from ultrasound measurement of the portal vein was higher at each level of LBNP post-compared with pre-HDBR. The gain of the cardiopulmonary baroreflex relating changes in total peripheral resistance to CVP was increased after HDBR, but splanchnic vascular resistance was actually reduced. These results are consistent with our hypothesis and suggest that cardiovascular instability following only 4-h HDBR might be related to altered hormonal and/or neural control of regional vascular resistance. Impaired ability to distribute blood away from the splanchnic region was associated with reduced stroke volume, elevated heart rate, and the inability to protect mean arterial pressure.
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Affiliation(s)
- D Fischer
- Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON, Canada
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25
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Nowak L, Nowak FG, Janko S, Dorwarth U, Hoffmann E, Botzenhardt F. Investigation of Various Types of Neurocardiogenic Response to Head-Up Tilting by Extended Hemodynamic and Neurohumoral Monitoring. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2007; 30:623-30. [PMID: 17461872 DOI: 10.1111/j.1540-8159.2007.00723.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The pathophysiology of neurocardiogenic syncope is heterogeneous. This study aim was to analyze whether extended monitoring during tilt-table testing provided additional information on the hemodynamic and vegetative state prior to neurocardiogenic syncope. METHODS This retrospective analysis is based on data of head-up tilt-table testing of 40 unselected consecutive patients with a history of unexplained syncope. For optimized characterization of the type of syncope, monitoring included electrocardiogram (ECG), blood pressure measurements and cardiac output, peripheral vascular resistance and contractility index measurements by impedance cardiography, as well as epinephrine and norepinephrine plasma levels in supine position and every 5 min during tilting. RESULTS Seven of 40 patients were unsuitable for analysis because of incomplete data sets. Tilt-table was positive in 26 patients, negative in 7. Groups did not differ in hemodynamic and catecholaminergic parameters at baseline. Responses to tilting were VASIS 1 (mix of cardioinhibitory and vasodepressor) in 5 patients, VASIS 2B (cardioinhibitory with asystole >3 sec) in 3, VASIS 3 (vasodepressor) in 16, orthostatic dysregulation in 2. In VASIS 1, the catecholamine measurement 4 min before syncope showed a proportionally larger increase of the epinephrine level than of norepinephrine. This disproportion was not observed in VASIS 2B and 3. In VASIS 2B, strong vasoconstriction and negative inotropy were evident in the presyncopal period. In VASIS 3, vascular resistance decreased continuously before syncope, while contractility index increased inadequately. Presyncopal epinephrine surge or norepinephrine loss was not observed in this group, suspecting other vasodilating factors. CONCLUSIONS Extended monitoring by impedance cardiography and plasma catecholamine measurements during tilt-table testing gave further insight into different hemodynamic and neurohumoral presyncopal patterns among the various types of neurocardiogenic syncope and may thereby help to develop individualized therapeutic concepts.
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Affiliation(s)
- Lorenz Nowak
- Staedtisches Klinikum Muenchen GmbH, Klinikum Bogenhausen, Department of Cardiology and Intensive Care Unit, Munich, Germany.
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Barrett LK, Singer M, Clapp LH. Vasopressin: mechanisms of action on the vasculature in health and in septic shock. Crit Care Med 2007; 35:33-40. [PMID: 17133186 DOI: 10.1097/01.ccm.0000251127.45385.cd] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Vasopressin is essential for cardiovascular homeostasis, acting via the kidney to regulate water resorption, on the vasculature to regulate smooth muscle tone, and as a central neurotransmitter, modulating brainstem autonomic function. Although it is released in response to stress or shock states, a relative deficiency of vasopressin has been found in prolonged vasodilatory shock, such as is seen in severe sepsis. In this circumstance, exogenous vasopressin has marked vasopressor effects, even at doses that would not affect blood pressure in healthy individuals. These two findings provide the rationale for the use of vasopressin in the treatment of septic shock. However, despite considerable research attention, the mechanisms for vasopressin deficiency and hypersensitivity in vasodilatory shock remain unclear. OBJECTIVE To summarize vasopressin's synthesis, physiologic roles, and regulation and then review the literature describing its vascular receptors and downstream signaling pathways. A discussion of potential mechanisms underlying vasopressin hypersensitivity in septic shock follows, with reference to relevant clinical, in vivo, and in vitro experimental evidence. DATA SOURCE Search of the PubMed database (keywords: vasopressin and receptors and/or sepsis or septic shock) for articles published in English before May 2006 and manual review of article bibliographies. DATA SYNTHESIS AND CONCLUSIONS The pathophysiologic mechanism underlying vasopressin hypersensitivity in septic shock is probably multifactorial. It is doubtful that this phenomenon is merely the consequence of replacing a deficiency. Changes in vascular receptors or their signaling and/or interactions between vasopressin, nitric oxide, and adenosine triphosphate-dependent potassium channels are likely to be relevant. Further translational research is required to improve our understanding and direct appropriate educated clinical use of vasopressin.
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MESH Headings
- Antidiuretic Agents/pharmacology
- Antidiuretic Agents/therapeutic use
- Autonomic Nervous System Diseases/etiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Catecholamines/physiology
- Homeostasis/drug effects
- Homeostasis/physiology
- Humans
- Hypothalamo-Hypophyseal System/drug effects
- Hypothalamo-Hypophyseal System/physiology
- Intracellular Fluid/drug effects
- Intracellular Fluid/physiology
- Kidney/drug effects
- Kidney/physiopathology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Nitric Oxide/physiology
- Pituitary-Adrenal System/drug effects
- Pituitary-Adrenal System/physiology
- Receptors, Oxytocin/drug effects
- Receptors, Oxytocin/physiology
- Receptors, Vasopressin/drug effects
- Receptors, Vasopressin/physiology
- Shock, Septic/drug therapy
- Shock, Septic/etiology
- Shock, Septic/physiopathology
- Sodium-Potassium-Exchanging ATPase/drug effects
- Sodium-Potassium-Exchanging ATPase/physiology
- Vasoconstrictor Agents/pharmacology
- Vasoconstrictor Agents/therapeutic use
- Vasopressins/pharmacology
- Vasopressins/physiology
- Vasopressins/therapeutic use
- Water-Electrolyte Balance/drug effects
- Water-Electrolyte Balance/physiology
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Affiliation(s)
- Lucinda K Barrett
- Department of Medicine and Wolfson Institute for Biomedical Research, University College London, London, UK
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Moreto V, Stabile AM, Antunes-Rodrigues J, Carnio EC. Role of heme-oxygenase pathway on vasopressin deficiency during endotoxemic shock-like conditions. Shock 2006; 26:472-6. [PMID: 17047517 DOI: 10.1097/01.shk.0000230301.86139.6a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The septic shock is characterized by decrease in median arterial pressure; many researchers have been related a deficiency in vasopressin release during the septic shock. Lipopolysaccharide administration is used to induce septic shock model in animals. We investigated the heme-oxygenase (HO) inhibition during the endotoxemic shock-like conditions. The LPS administration induced a significant decrease in MAP (-15.4 +/- 1.2 mmHg at second hour, -25.8 +/- 8.7 mmHg at fourth hour, and -22.3 +/- 8.6 mmHg at sixth hour) with a concomitant increase in heart rate (486.3 +/- 55.0, 531.8 +/- 53.8, and 510.0 +/- 55.3 bpm, respectively), a significant decrease in diuresis (from 1.1 +/- 0.7 to 0.4 +/- 0.3/100g body weight at fourth hour), and a transitory decrease in body temperature (from 37.0 +/- 0.5 to 35.4 +/- 0.8 degrees C at second hour). An increase in plasma arginine vasopressin (AVP) concentration (from 3.2 +/- 0.9 to 19.0 +/- 5.7 pg/mL at the first hour) occurred in these animals and was present for 2 h after LPS administration, returning close to basal levels thereafter and remaining unchanged until the end of the experiment. When LPS was combined with the i.c.v. administration of HO inhibitor, we observed a sustained increase in plasma AVP concentration, attenuation in the drop of MAP, and increase in antidiuresis induced by LPS treatment. These data suggest that central HO pathway may activate a control mechanism that attenuates AVP secretion during endotoxemia and may consequently regulate the MAP and diuretic output.
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Affiliation(s)
- Viviana Moreto
- Departamento de Enfermagem Geral e Especializada, Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Curgunlu A, Vural P, Canbaz M, Erten N, Karan MA, Tascioglu C. Plasma nitrate/nitrite and endothelin-1 in patients with liver cirrhosis. J Clin Lab Anal 2005; 19:177-81. [PMID: 16170811 PMCID: PMC6807778 DOI: 10.1002/jcla.20074] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The aims of this study were to examine the plasma nitrate/nitrite (NOx; two end products of nitric oxide metabolism) and endothelin-1 (ET-1) concentrations in patients with liver cirrhosis, and to investigate whether there is a relationship between these two vasoactive parameters and the course of disease. Twenty-eight patients with liver cirrhosis (11 HBV-related, four HCV-related, four alcohol-related, and nine with idiopathic etiology) and 25 healthy subjects (controls) were included in the study. The venous plasma concentrations of NOx and ET-1 were significantly higher (P<0.01 and P<0.001) in the patients with cirrhosis than in the controls. A significant increase in ET-1 was observed in the Child B subgroup vs. Child A (P<0.05), and in the Child C subgroup vs. either subgroup A or B (P<0.05). There were no statistical differences between study subgroups (Child A-C) in the mean of NOx values. Plasma NOx and ET-1 were significantly increased in patients with ascites compared to those without ascites (P<0.05 and P<0.01). Increased nitric oxide synthesis may be a compensation mechanism against endothelial injury. The highest ET-1 levels in Child C and moderately increased ET-1 levels in Child B, and the lower increase of ET-1 levels in Child A patients suggest that plasma ET-1 increases with the progression of the disease. The fact that NOx and ET-1 levels were higher in patients with decompensated cirrhosis (patients with ascites) than in those with compensated cirrhosis (patients without ascites), and the presence of a strong correlation between ET-1, NOx, and the degree of varices, supports the suggestion that there is a relationship between NOx, ET-1, and portal hypertension. Our study demonstrates that increased ET and nitric oxide metabolism is associated with the hemodynamic alterations induced by portal hypertension.
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Affiliation(s)
- Asli Curgunlu
- Department of Internal Medicine, Cerrahpasa Medical Faculty, Istanbul, Turkey
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Winker R, Garland EM, Rüdiger HW, Diedrich A, Biaggioni I, Ponocny I, Cascorbi I, Robertson D. Influence of an insertion variant in the 5'UTR of the endothelin-1 gene on orthostatic intolerance. Am J Med Sci 2005; 330:166-71. [PMID: 16234608 DOI: 10.1097/00000441-200510000-00003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Orthostatic intolerance is a multifactorial disease in which the genetic contribution is probably the result of a number of genes acting in combination. Recent work has shown that orthostatic intolerance is influenced by endothelial nitric oxide synthase gene polymorphisms. Since endothelin-1 (ET-1) is one of the most important vasoconstrictor peptides, a frequent adenine insertion polymorphism within the 5'-untranslated region (5'UTR), which is of functional importance for ET-1 expression, could influence orthostatic intolerance. The aim of this study was therefore to ascertain whether this frequent variant of the endothelin-1 gene influences the risk for orthostatic intolerance. METHODS We studied 257 white patients (120 cases with orthostatic intolerance and 137 controls) for genotyping of the 5'UTR I variant. From this cohort, 111 patients and 99 control subjects underwent a tilt-table test or an upright posture study, including monitoring of blood pressure, heart rate, and plasma catecholamines, in the supine position and during 30 minutes of standing. Genotyping was performed in all participants. Chi tests of independence were used to test for associations between orthostatic intolerance and genotype. In addition, an association of the insertion polymorphism with hemodynamic variables (heart rate, supine and upright blood pressure) was ascertained using one-way analysis of variance. RESULTS The 5'UTR I variant was significantly less common in patients with orthostatic intolerance (allele frequency 0.36 and 0.28, in controls and cases, respectively). Additionally, we found a significant decrease in the risk of orthostatic intolerance among people who were homozygous for the 5'UTR variant (I/I) compared with the wild-type variant (D/D) (odds ratio, 0.41; 95% confidence interval, 0.17 to 0.97; P = 0.04). No association between the 5'UTR variant and heart rate or blood pressure regardless of diagnosis was found. CONCLUSIONS Our current results suggest that the hereditary adenine insertion variant in the 5'-UTR of the endothelin-1 gene is protective for orthostatic intolerance. The increased ET-1 protein expression that has been linked with the I variant might be associated with a more efficient hemodynamic response to standing. This is likely one of several common genetic loci that may represent modifiers of orthostatic intolerance phenotypes.
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Affiliation(s)
- Robert Winker
- Division of Occupational Medicine, Medical University of Vienna, Vienna, Austria.
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Magerkurth C, Riedel A, Braune S. Permanent increase in endothelin serum levels in vasovagal syncope. Clin Auton Res 2005; 15:299-301. [PMID: 16032385 DOI: 10.1007/s10286-005-0291-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 04/24/2005] [Indexed: 10/25/2022]
Abstract
Of 40 normal volunteers tilted on two separate occasions, seven subjects had vasovagal syncope only during one upright tilt, but showed increased endothelin plasma levels in the supine position and during head-up tilt on both occasions, independent of vasovagal syncope, compared to control subjects.
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Van Beneden R, Gurné O, Selvais PL, Ahn SA, Robert AR, Ketelslegers JM, Pouleur HG, Rousseau MF. Superiority of big endothelin-1 and endothelin-1 over natriuretic peptides in predicting survival in severe congestive heart failure: a 7-year follow-up study. J Card Fail 2005; 10:490-5. [PMID: 15599839 DOI: 10.1016/j.cardfail.2004.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Plasma concentrations of atrial and brain natriuretic peptides (ANP, BNP), of their N-terminal pro-peptides, of endothelin-1 (ET-1), and big endothelin-1 (big ET-1) have diagnostic and prognostic significance in congestive heart failure (CHF). However, their respective values as a predictor of survival remain controversial and have never been directly compared in severe CHF. METHODS AND RESULTS We analyzed, in 47 patients with severe CHF (New York Heart Association [NYHA] class III to IV; age 66 +/- 8 years, ejection fraction 20 +/- 6%), the prognostic performance of a panel of neurohormones and assays (N-terminal pro-ANP 1-25, 68-98 by radioimmunoassay [RIA], and 1-98 by enzyme-linked immunosorbent assay [ELISA], BNP by RIA and immunoradiometric assay [IRMA], N-terminal pro-BNP by Elisa, ET-1 by RIA, and big ET-1 by RIA and Elisa. Data were compared with 40 patients with mild to moderate CHF [NYHA I-II] and 30 healthy subjects. After a follow-up of 81 +/- 15 months, there were 34 deaths and 1 heart transplant. All neurohormones were significantly higher at baseline in patients with severe than in mild to moderate CHF or healthy subjects (all P < .001). Although all neurohormones but BNP IRMA were significant predictors of survival in univariate analysis, only big ET-1 RIA and ET-1 were independent predictors of survival (improvement chi(2): 7.5 and 4.6, P < .01 and P < .05). Using medians as cutpoints of big ET-1 RIA and ET-1, 2 severe CHF populations were defined with a different outcome (5-year survival: 55 versus 18%, P < .01). CONCLUSIONS Big ET-1 and ET-1 are strong independent predictors of survival in patients with severe CHF and better for this purpose than natriuretic peptides or their pro-peptides. These markers allow easily to identify a population with a very high risk mortality eligible for more aggressive therapies.
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Affiliation(s)
- Ronald Van Beneden
- Diabetes and Nutrition Unit, Division of Cardiology, School of Public Health, University of Louvain, B-1200 Brussels, Belgium
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Affiliation(s)
- Robert W Schrier
- Department of Medicine, University of Colorado Health Sciences Center, Denver 80262, USA.
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Xiang S, Denver R, Bailey M, Krum H. Physiologic determinants of endothelin concentrations in human saliva. Clin Chem 2003; 49:2012-9. [PMID: 14633872 DOI: 10.1373/clinchem.2003.020875] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Salivary endothelin (ET) concentrations have been shown to correlate with disease severity in patients with chronic heart failure (CHF). We undertook the present study to evaluate the stability of salivary ET under different handling conditions to assess its suitability as a biochemical marker in screening, diagnosis, and management of CHF. METHODS Saliva samples were collected from healthy individuals and/or CHF patients, subjected to different handling conditions, and then stored at -80 degrees C until assayed by an ELISA for ET. RESULTS Salivary ET concentrations showed a time-dependent increase during storage at room temperature. After 72 h of incubation at room temperature, ET increased approximately 2.8-fold (P = 0.03). Simultaneously, salivary big ET showed a time-dependent 11.2-fold decrease (P <0.0001). This activity was blocked by an ET-converting enzyme (ECE) inhibitor, suggesting that these changes were attributable to ECE-dependent cleavage of endogenous big ET in saliva. Ex vivo conversion was also observed when samples were stored at 4 degrees C, but the magnitude of these changes was markedly smaller (P <0.0001). Posture also affected salivary ET concentrations in CHF patients. With a change from supine to seated rest, salivary ET concentrations increased 1.5- and 1.8-fold after 20 and 40 min, respectively (P = 0.01). With a return to supine rest, salivary ET concentrations returned to baseline concentrations (P = 0.008). CONCLUSIONS These data suggest that saliva sampling and handling conditions could markedly affect measurement of salivary ET. In particular, care should be taken to minimize ECE-dependent enzymatic conversion of endogenous big ET in saliva.
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Affiliation(s)
- Sue Xiang
- Department of Medicine and Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, Victoria 3004, Australia
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Robin JK, Oliver JA, Landry DW. Vasopressin deficiency in the syndrome of irreversible shock. THE JOURNAL OF TRAUMA 2003; 54:S149-54. [PMID: 12768118 DOI: 10.1097/01.ta.0000064523.93060.60] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Jennie K Robin
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Béchir M, Binggeli C, Corti R, Chenevard R, Spieker L, Ruschitzka F, Lüscher TF, Noll G. Dysfunctional baroreflex regulation of sympathetic nerve activity in patients with vasovagal syncope. Circulation 2003; 107:1620-5. [PMID: 12668496 DOI: 10.1161/01.cir.0000056105.87040.2b] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The interplay of resting muscle sympathetic nerve activity (MSA) and the baroreceptor reflex in patients with vasovagal syncope remains elusive. Hence, the aim of the present study was to investigate MSA, baroreceptor sensitivity, heart rate, and blood pressure under resting conditions and during orthostatic stress in patients with a history of vasovagal syncope. METHODS AND RESULTS MSA was measured using microneurography at rest and during lower body negative pressure (LBNP) to mimic orthostatic stress in patients with a history of vasovagal syncope (n=10) and in age-matched healthy controls (n=8). Heart rate and blood pressure were simultaneously recorded. Cardiac baroreceptor sensitivity was calculated with the spectral technique (alpha coefficient). Resting MSA in the patients with syncope was significantly increased as compared with controls (42.4+/-2.3 versus 26.5+/-3.6 bursts/min, P=0.001), whereas activation of MSA during orthostatic stress in the patient group was significantly blunted (5.1+/-1.6 versus 15.2+/-2.1 bursts/min at LBNP -50 mm Hg, P=0.002). In the patients with syncope, cardiac baroreceptor sensitivity was significantly reduced under supine resting conditions (8.5+/-0.7 versus 13.0+/-1.1 ms/mm Hg, P=0.001), as well as under orthostatic stress (7.3+/-0.7 versus 13.4+/-1.5 ms/mm Hg, P=0.003). CONCLUSIONS This study shows that in patients with vasovagal syncope, resting MSA is increased and baroreflex regulation during orthostatic stress is blunted, thus leading to impaired MSA adaptation. These results provide new insights into mechanisms of vasovagal syncope and suggest that pharmacological modulation of baroreceptor sensitivity may represent a promising treatment of neuromediated syncope.
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Affiliation(s)
- Markus Béchir
- Cardiovascular Center, Cardiology, University Hospital, Rämistrasse 100, 8091 Zürich, Switzerland
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36
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Affiliation(s)
- Mark Barlow
- Emergency Department, Wellington Hospital, Wellington, New Zealand.
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Braune S, Riedel A, Schulte-Mönting J, Raczek J. Influence of a radiofrequency electromagnetic field on cardiovascular and hormonal parameters of the autonomic nervous system in healthy individuals. Radiat Res 2002; 158:352-6. [PMID: 12175313 DOI: 10.1667/0033-7587(2002)158[0352:ioaref]2.0.co;2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The potential health risks of radiofrequency electromagnetic fields (EMFs) emitted by mobile phones are of considerable public interest. The present study investigated the hypothesis, based on the results of our previous study, that exposure to EMFs can increase sympathetic vasoconstrictor activity. Forty healthy young males and females underwent a single-blind, placebo-controlled protocol once on each of two different days. Each investigation included successive periods of placebo and EMF exposure, given in a randomized order. The exposure was implemented by a GSM-like signal (900 MHz, pulsed with 217 Hz, 2 W) using a mobile phone mounted on the right-hand side of the head in a typical telephoning position. Each period of placebo exposure and of EMF exposure consisted of 20 min of supine rest, 10 min of 70 degrees upright tilt on a tilt table, and another 20 min of supine rest. Blood pressure, heart rate and cutaneous capillary perfusion were measured continuously. In addition, serum levels of norepinephrine, epinephrine, cortisol and endothelin were analyzed in venous blood samples taken every 10 min. Similar to the previous study, systolic and diastolic blood pressure each showed slow, continuous, statistically significant increases of about 5 mmHg during the course of the protocol. All other parameters either decreased in parallel or remained constant. However, analysis of variance showed that the changes in blood pressure and in all other parameters were independent of the EMF exposure. These findings do not support the assumption of a nonthermal influence of EMFs emitted by mobile phones on the cardiovascular autonomic nervous system in healthy humans.
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Affiliation(s)
- S Braune
- Department of Neurology, University of Freiburg, Germany.
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Elijovich F, Laffer CL. Participation of renal and circulating endothelin in salt-sensitive essential hypertension. J Hum Hypertens 2002; 16:459-67. [PMID: 12080429 DOI: 10.1038/sj.jhh.1001419] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Salt sensitivity of blood pressure is a cardiovascular risk factor, independent of and in addition to hypertension. In essential hypertension, a conglomerate of clinical and biochemical characteristics defines a salt-sensitive phenotype. Despite extensive research on multiple natriuretic and antinatriuretic systems, there is no definitive answer yet about the major causes of salt-sensitivity, probably reflecting the complexity of salt-balance regulation. The endothelins, ubiquitous peptides first described as potent vasoconstrictors, also have vasodilator, natriuretic and antinatriuretic actions, depending on their site of generation and binding to different receptors. We review the available data on endothelin in salt-sensitive essential hypertension and conclude that abnormalities of renal endothelin may play a primary role. More importantly, the salt-sensitive patient may have blood pressure-dependency on endothelin in all states of salt balance, thus predicting that endothelin receptor blockers will have a major therapeutic role in salt-sensitive essential hypertension.
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Affiliation(s)
- F Elijovich
- Department of Medicine, College of Human Medicine, Michigan State University, Medical Education and Research Center of Grand Rapids, 49503, USA.
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Giusti-Paiva A, De Castro M, Antunes-Rodrigues J, Carnio EC. Inducible nitric oxide synthase pathway in the central nervous system and vasopressin release during experimental septic shock. Crit Care Med 2002; 30:1306-10. [PMID: 12072686 DOI: 10.1097/00003246-200206000-00025] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Septic shock is characterized by arteriolar vasodilation and hypotension. We have tested the hypothesis that nitric oxide arising from inducible nitric oxide synthase in the central nervous system is responsible for the deficiency in vasopressin release and consequent hypotension during experimental septic shock. METHODS AND RESULTS Septic shock was induced in male Wistar rats by intravenous injection of 1.5 mg/kg lipopolysaccharide. After lipopolysaccharide administration, we found a significant decrease in mean arterial pressure with a concomitant increase in heart rate, a significant decrease in diuresis, and a transitory decrease in body temperature. An increase in plasma vasopressin concentrations occurred in these animals and was present for 2 hrs after lipopolysaccharide administration, returning close to basal concentrations thereafter and remaining unchanged for the next 24 hrs. When lipopolysaccharide was combined with central administration of aminoguanidine, an inducible nitric oxide synthase inhibitor, we observed a sustained increase in plasma vasopressin concentration and in the maintenance of blood pressure at 4 and 6 hrs after lipopolysaccharide treatment compared with rats treated with lipopolysaccharide alone. CONCLUSION These data indicate that central nitric oxide arising from the inducible nitric oxide synthase pathway plays an important inhibitory role in vasopressin release during experimental septic shock and may be responsible for the hypotension occurring in this vasodilatory shock.
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Affiliation(s)
- Alexandre Giusti-Paiva
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto-SP, Brasil
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Affiliation(s)
- Horacio Kaufmann
- Mount Sinai School of Medicine, Department of Neurology, New York, New York 10029, USA
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Abstract
BACKGROUND Syncope is caused by a severe but reversible reduction in blood flow to the brain stem neurons responsible for supporting consciousness (reticular activating system). Neurally mediated syncope, also referred to as vasovagal or reflex syncope, is the most frequent cause of loss of consciousness in apparently normal subjects. REVIEW SUMMARY Neurally mediated syncope is believed to be a reflex response with afferent, central, and efferent pathways. Characteristic autonomic changes in neurally mediated syncope are an increase in parasympathetic efferent activity causing bradycardia and a reduction in sympathetic vasoconstrictor outflow causing vasodilatation. Premonitory symptoms, such as nausea, diaphoresis, abdominal discomfort, and blurred vision, are caused by autonomic activation and are distinguishing features of neurally mediated syncope. Neurally mediated syncope frequently has a characteristic trigger, although this may not be apparent. Testing orthostatic tolerance during passive head-up tilt is the best available diagnostic procedure to evaluate patients with syncope in whom a cardiac cause has been excluded. In many cases, once the diagnosis of neurally mediated syncope is confirmed, it may suffice to reassure the patient and teach him to avoid known triggers and to recognize and act upon early warning symptoms. Because subjects with neurally mediated syncope may potentially be sodium depleted, increasing salt intake can be beneficial in improving their orthostatic intolerance. CONCLUSIONS Neurally mediated syncope is the most common form of syncope in healthy adults. The best diagnostic tools are the clinical history and passive head-up tilt. The best treatment strategies are the avoidance of triggering factors as well as intravascular volume expansion.
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Affiliation(s)
- Horacio Kaufmann
- Autonomic Nervous System Laboratory, Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Hidestål J, Fredriksen S, Hallén M, Westerdahl J, Thysell H, Bodelsson M. Hypersensitivity to noradrenaline in human omental vein but not artery isolated from a patient with idiopathic orthostatic hypotension. Auton Neurosci 2002; 97:55-8. [PMID: 12036187 DOI: 10.1016/s1566-0702(02)00015-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We investigated the smooth muscle contraction in response to noradrenaline (NA), endothelin-1 (ET) and 5-hydroxytryptamine (5-HT) in the omental artery and vein segments from a 67-year-old woman with idiopathic orthostatic hypotension. The blood vessels were obtained during the abdominal surgery and investigated in vitro. Noradrenaline, endothelin-1 and 5-hydroxytryptamine all induced a contraction in the artery and vein segments. Compared to the literature, the sensitivity to noradrenaline was 10 times higher than expected in the vein. In the artery, the sensitivity to noradrenaline and in both the artery and vein, the sensitivity to endothelin-1 and 5-hydroxytryptamine was similar to that reported in the literature. These results suggest that the patient had developed an isolated hypersensitivity to noradrenaline in the veins, probably due to an impairment of the sympathetic activity.
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Affiliation(s)
- Joakim Hidestål
- Department of Anaesthesia and Intensive Care, University Hospital, Lund, Sweden
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Selvais PL, Rousseau LJ, Ahn SA, Van Linden F, Ketelslegers JM, Rousseau MF. Usefulness of the supine-rest maneuver before neurohormonal sampling. Am J Cardiol 2002; 89:772-4. [PMID: 11897225 DOI: 10.1016/s0002-9149(01)02354-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Philippe L Selvais
- Division of Cardiology and Unit of Diabetes and Nutrition, University of Louvain, Brussels, Belgium
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Abstract
Neurocardiogenic syncope is the most common cause of syncope presenting in the outpatient setting. It is usually encountered among individuals without an underlying heart disease, but not uncommonly participates in the syncope mechanism of patients with an obstructive or an arrhythmic cardiac cause for syncope as well. The vasovagal event is caused by a transient profound hypotensive reaction most commonly associated with inappropriate bradycardia resulting from activation of a complex autonomic reflex. The pathophysiology of neurocardiogenic syncope has been elucidated by tilt table testing, a noninvasive and well-tolerated method for reproducing the event in susceptible individuals. Although the majority of people with vasovagal fainting need no specific treatment, treatment is required for those presenting with problematic features such as frequent events accompanied by trauma or accidents, and occasionally by a severe cardioinhibitory pattern response. A number of different drugs have been proposed to favourably act on different aspects of the neurocardiogenic reflex but only a few randomised, placebo-controlled, drug-specific trials are currently available. Alternatively, cardiac pacing has also been introduced for patients who have symptoms that are drug-refractory or for those with a severe cardioinhibitory hypotensive response. The selection of the appropriate treatment plan should be individualised after consideration of patient history, clinical characteristics and preference, results of the baseline tilting study, and the existing evidence from the few randomised, controlled studies performed so far.
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Affiliation(s)
- K A Gatzoulis
- University Department of Cardiology, Hippokration General Hospital, Athens, Greece
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Spieker LE, Noll G, Ruschitzka FT, Lüscher TF. Endothelin A receptor antagonists in congestive heart failure: blocking the beast while leaving the beauty untouched? Heart Fail Rev 2001; 6:301-15. [PMID: 11447305 DOI: 10.1023/a:1011456309039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Congestive heart failure (CHF) is a disease process characterized by impaired left ventricular function, increased peripheral and pulmonary vascular resistance and reduced exercise tolerance and dyspnea. Thus, mediators involved in the control of myocardial function and vascular tone may be involved in its pathophysiology. The family of endothelins (ET) consists of four closely related peptides, ET-1, ET-2, ET-3, and ET-4, which cause vasoconstriction, cell proliferation, and myocardial effects through activation of ET(A) receptors. In contrast, endothelial ET(B) receptors mediate vasodilation via release of nitric oxide and prostacyclin. In addition, ET(B) receptors in the lung are a major pathway for the clearance of ET-1 from plasma. Thus, infusion of an ET(A) receptor antagonist into the brachial artery in healthy humans leads to vasodilation whereas infusion of an ET(B) receptor antagonist causes vasoconstriction. ET-1 plasma levels are elevated in CHF and correlate both with the hemodynamic severity and with symptoms. Plasma levels of ET-1 and its precursor, big ET-1, are strong independent predictors of death in patients after myocardial infarction and with CHF. ET-1 contributes to increased systemic and pulmonary vascular resistance, vascular dysfunction, myocardial ischemia, and renal impairment in CHF. Selective ET(A) as well as combined ET(A/B) receptor antagonists have been studied in patients with CHF showing impressive hemodynamic improvements (i.e. reduced peripheral vascular and pulmonary resistance as well as increased cardiac output). These results indicate that ET receptor antagonists indeed have a potential to improve hemodynamics, symptoms, and potentially prognosis of CHF which still carries a high mortality.
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Affiliation(s)
- L E Spieker
- Cardiology, University Hospital, Zürich, Switzerland
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Abstract
Vasopressin (antidiuretic hormone) is emerging as a potentially major advance in the treatment of a variety of shock states. Increasing interest in the clinical use of vasopressin has resulted from the recognition of its importance in the endogenous response to shock and from advances in understanding of its mechanism of action. From animal models of shock, vasopressin has been shown to produce greater blood flow diversion from non-vital to vital organ beds (particularly the brain) than does adrenaline. Although vasopressin has similar direct actions to the catecholamines, it may uniquely also inhibit some of the pathologic vasodilator processes that occur in shock states. There is current interest in the use of vasopressin in the treatment of shock due to ventricular fibrillation, hypovolaemia, sepsis and cardiopulmonary bypass. This article reviews the physiology and pharmacology of vasopressin and all of the relevant animal and human clinical literature on its use in the treatment of shock following a MEDLINE (1966-2000) search.
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Affiliation(s)
- P Forrest
- Department of Anaesthesia, Royal Prince Alfred Hospital, Sydney, Australia
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47
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Affiliation(s)
- D W Landry
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Theopistou A, Gatzoulis K, Economou E, Sideris S, Hantzos K, Stefanadis C, Toutouzas P. Biochemical changes involved in the mechanism of vasovagal syncope. Am J Cardiol 2001; 88:376-81. [PMID: 11545757 DOI: 10.1016/s0002-9149(01)01682-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Vasovagal syncope elicits one of the most powerful transient vasodilatory responses in humans. Many studies have shown an altered neurohumoral response to tilting in patients with vasovagal syncope. Vasopressin (VP) has been of particular interest, but its exact role remains unclarified, whereas the possible role of the potent vasoactive end products of arachidonic acid metabolism has not yet been addressed. We determined the changes in plasma levels of VP, thromboxane (TXA2), and prostacyclin (PGI2) in 34 syncopal patients undergoing a standardized head-up tilt-table testing protocol and compared these changes between patients with positive and negative test results. Blood samples were collected at baseline, 15 minutes in the head-up position, and at the termination of the tilt test (the induction of syncope or the completion of a negative test). Sixteen patients had a positive test result, whereas 18 completed the test without developing any syncopal symptoms. In the tilt-positive group, VP levels presented a 20-fold increase at the time of syncope when compared with baseline levels (p = 0.0000), without any increase at earlier stages. No change was detected at any stage in the tilt-negative patients. We did not find any difference in the levels of PGI2 at any stage in any group of patients or between the 2 groups. TXA2 levels increased significantly at 15 minutes in the upright position in both tilt-positive and tilt-negative patients. No further increase was noticed at the time of syncope in the tilt-positive group, whereas in patients with a negative test result, there was a tendency to decline at the time of the test's completion. It is concluded that although VP is markedly increased during tilt-induced vasovagal syncope, vasoactive amines such as TXA2 and PGI2 play a minor role in the vasodilatory component of the response.
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Affiliation(s)
- A Theopistou
- Department of Cardiology, Hippokration Hospital, University of Athens, Athens, Greece.
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Abstract
The mild vasoconstrictor effects of modern antimigraine drugs, such as serotonin (5-HT; 5-hydroxytryptamine)1B/D agonists, have led to a search for nonvasoconstrictor approaches to therapy. Such approaches have included substance P (neurokinin I) antagonists, endothelin antagonists and highly specific 5HT1D agonists. All of these substances are effective in animal models and have no significant vasoconstrictive effects. However, all of them failed to demonstrate any antimigraine effects. Current clinical and experimental evidence therefore supports the view that isolated peripheral trigeminal nerve inhibition is insufficient to relieve acute migraine.
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Affiliation(s)
- A May
- Department of Neurology, University of Regensburg, Regensburg, Germany.
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