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https://www.readbyqxmd.com/read/28443680/periodic-breathing-during-incremental-exercise
#1
Piergiuseppe Agostoni, Ugo Corrà, Michele Emdin
Periodic breathing during incremental cardiopulmonary exercise testing is a regularly recurring waxing and waning of tidal volume due to oscillations in central respiratory drive. Periodic breathing is a sign of respiratory control system instability, which may occur at rest or during exercise. The possible mechanisms responsible of exertional periodic breathing might be related to any instability of the ventilatory regulation caused by: 1) increased circulatory delay (i.e., circulation time from the lung to the brain and chemoreceptors, due to reduced cardiac index leading to delay in information transfer), 2) increase in controller gain (i...
April 26, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28443506/catestain-a-master-regulator-of-cardiovascular-functions
#2
Sushil K Mahata, Malapaka Kiranmayi, Nitish R Mahapatra
Cardiovascular disease (CVD), the most common cause of death globally, accounts for ~30% of all deaths worldwide. Hypertension is a common contributor to morbidity and mortality from CVD. The plasma concentration of chromogranin A (CgA) is elevated in patients with CVD as well as patients with established human essential hypertension and heart failure (HF). In contrast, the plasma level of the CgA-derived peptide catestatin (CST) is diminished in human essential hypertension. Low conversion of CgA-to-CST has been associated with increased mortality in patients hospitalized with acute HF...
April 24, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28424627/blood-pressure-increase-during-oxygen-supplementation-in-chronic-kidney-disease-patients-is-mediated-by-vasoconstriction-independent-of-baroreflex-function
#3
René van der Bel, Müşerref Çalişkan, Robert A van Hulst, Johannes J van Lieshout, Erik S G Stroes, C T Paul Krediet
Renal hypoxia is thought to be an important pathophysiological factor in the progression of chronic kidney disease (CKD) and the associated hypertension. In a previous study among CKD patients, supplementation with 100% oxygen reduced sympathetic nerve activity (SNA) and lowered blood pressure (BP). We aimed to assess the underlying haemodynamic modulation and hypothesized a decreased systemic vascular resistance (SVR). To that end, 19 CKD patients were studied during 15-min intervals of increasing partial oxygen pressure (ppO2) from room air (0...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28420362/clinical-hemispheric-and-autonomic-changes-associated-with-use-of-closed-loop-allostatic-neurotechnology-by-a-case-series-of-individuals-with-self-reported-symptoms-of-post-traumatic-stress
#4
Charles H Tegeler, Jared F Cook, Catherine L Tegeler, Joshua R Hirsch, Hossam A Shaltout, Sean L Simpson, Brian C Fidali, Lee Gerdes, Sung W Lee
BACKGROUND: The objective of this pilot study was to explore the use of a closed-loop, allostatic, acoustic stimulation neurotechnology for individuals with self-reported symptoms of post-traumatic stress, as a potential means to impact symptomatology, temporal lobe high frequency asymmetry, heart rate variability (HRV), and baroreflex sensitivity (BRS). METHODS: From a cohort of individuals participating in a naturalistic study to evaluate use of allostatic neurotechnology for diverse clinical conditions, a subset was identified who reported high scores on the Posttraumatic Stress Disorder Checklist (PCL)...
April 19, 2017: BMC Psychiatry
https://www.readbyqxmd.com/read/28419371/sleep-a-window-into-autonomic-control-in-children-born-preterm-and-growth-restricted
#5
Stephanie R Yiallourou, Euan M Wallace, Christie Whatley, Alexsandria Odoi, Samantha Hollis, Aidan J Weichard, Jayan Shivanandhan Muthusamy, Suraj Varma, James Cameron, Om Narayan, Rosemary Sc Horne
Study Objectives: Preterm birth and fetal growth restriction (FGR) are both associated with risk of hypertension in adulthood. Mechanisms leading to this pathology are unclear. In children aged 5-12 years, who were born preterm and FGR, we used sleep as a tool to assess autonomic control with assessment of cardiovascular structure and function. Methods: 18 children born preterm and FGR, 15 born preterm with appropriate birth weights (AGA) and 20 AGA term-born children were studied...
April 17, 2017: Sleep
https://www.readbyqxmd.com/read/28399043/different-estimation-methods-of-spontaneous-baroreflex-sensitivity-have-different-predictive-value-in-heart-failure-patients
#6
Gian Domenico Pinna, Alberto Porta, Roberto Maestri, Beatrice De Maria, Laura Adelaide Dalla Vecchia, Maria Teresa La Rovere
OBJECTIVE: Several methods have been developed so far to estimate cardiac baroreflex sensitivity (BRS) through the analysis of spontaneous fluctuations of systolic arterial pressure (SAP) and R-R interval. Their relative performance in predicting cardiac mortality in heart failure patients is not known. The aim of this study was to compare the prognostic value of a set of representative indexes of spontaneous BRS in these patients. METHODS: We studied 228 stable, moderate-to-severe heart failure patients with reduced ejection fraction, in sinus rhythm, who underwent an 8-min supine recording of ECG, arterial blood pressure and respiration during paced breathing (15 breaths/min)...
April 10, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28396638/physiological-mechanisms-mediating-the-coupling-between-heart-period-and-arterial-pressure-in-response-to-postural-changes-in-humans
#7
Alessandro Silvani, Giovanna Calandra-Buonaura, Blair D Johnson, Noud van Helmond, Giorgio Barletta, Anna G Cecere, Michael J Joyner, Pietro Cortelli
The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBRS with the sequence technique in healthy male subjects during passive head-up tilt test (HUTT, n = 58), during supine wakefulness, supine slow-wave sleep (SWS), and in the seated and active standing positions (n = 8), and during progressive loss of 1 L blood (n = 8) to decrease central venous pressure in the supine position...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28389218/walking-training-at-the-heart-rate-of-pain-threshold-improves-cardiovascular-function-and-autonomic-regulation-in-intermittent-claudication-a-randomized-controlled-trial
#8
Marcel Chehuen, Gabriel G Cucato, Celso Ricardo F Carvalho, Raphael M Ritti-Dias, Nelson Wolosker, Anthony S Leicht, Cláudia Lúcia M Forjaz
OBJECTIVES: This study investigated the effects of walking training (WT) on cardiovascular function and autonomic regulation in patents with intermittent claudication (IC). DESIGN: Randomized controlled trial. METHODS: Forty-two male patients with IC (≥50years) were randomly allocated into two groups: control (CG, n=20, 30min of stretching exercises) and WT (WTG, n=22, 15 bouts of 2min of walking interpolated by 2min of upright rest-walking intensity was set at the heart rate of pain threshold)...
March 21, 2017: Journal of Science and Medicine in Sport
https://www.readbyqxmd.com/read/28388597/fetal-growth-restricted-preterm-infants-display-compromised-autonomic-cardiovascular-control-on-the-first-postnatal-day-but-not-during-infancy
#9
Emily Cohen, Flora Y Wong, Euan M Wallace, Joanne C Mockler, Alexsandria Odoi, Samantha Hollis, Rosemary S C Horne, Stephanie R Yiallourou
BACKGROUND: Fetal growth restriction (FGR) is associated with increased perinatal mortality and long-term cardiovascular and neurodevelopmental sequelae. We hypothesized that FGR impacts on the development of autonomic heart rate and blood pressure control, contributing to unfavorable short- and long-term outcomes following FGR. METHODS: We studied 25 preterm FGR and 22 preterm and 19 term appropriate-for-gestational-age (AGA) infants. Preterm neonates were studied on postnatal Day 1 and all infants were studied at 1 and 6 months post-term age...
April 7, 2017: Pediatric Research
https://www.readbyqxmd.com/read/28386627/baroreflex-gain-and-vasomotor-sympathetic-modulation-in-resistant-hypertension
#10
Isabelle Magalhães Guedes Freitas, Leonardo Barbosa de Almeida, Natália Portela Pereira, Pedro Augusto de Carvalho Mira, Rogério Baumgratz de Paula, Daniel Godoy Martinez, Edgar Toschi-Dias, Mateus Camaroti Laterza
PURPOSE: The aim of this study was to determine the gain and latency of arterial baroreflex control of heart rate in patients with resistant hypertension compared to patients with essential hypertension and normotensive subjects. METHODS: Eighteen patients with resistant hypertension (56 ± 10 years, mean of four antihypertensive drugs), 17 patients with essential hypertension (56 ± 11 years, mean of two antihypertensive drugs), and 17 untreated normotensive controls (50 ± 15 years) were evaluated by spectral analysis of the spontaneous fluctuations of arterial pressure (beat-to-beat) and heart rate (ECG)...
April 6, 2017: Clinical Autonomic Research: Official Journal of the Clinical Autonomic Research Society
https://www.readbyqxmd.com/read/28386233/elastase-2-a-tissue-alternative-pathway-for-angiotensin-ii-generation-plays-a-role-in-circulatory-sympathovagal-balance-in-mice
#11
Christiane Becari, Marina T Durand, Alessander O Guimaraes, Renata M Lataro, Cibele M Prado, Mauro de Oliveira, Sarai C O Candido, Paloma Pais, Mauricio S Ribeiro, Michael Bader, Joao B Pesquero, Maria C O Salgado, Helio C Salgado
In vitro and ex vivo experiments indicate that elastase-2 (ELA-2), a chymotrypsin-serine protease elastase family member 2A, is an alternative pathway for angiotensin II (Ang II) generation. However, the role played by ELA-2 in vivo is unclear. We examined ELA-2 knockout (ELA-2KO) mice compared to wild-type (WT) mice and determined whether ELA-2 played a role in hemodynamics [arterial pressure (AP) and heart rate (HR)], cardiocirculatory sympathovagal balance and baroreflex sensitivity. The variability of systolic arterial pressure (SAP) and pulse interval (PI) for evaluating autonomic modulation was examined for time and frequency domains (spectral analysis), whereas a symbolic analysis was also used to evaluate PI variability...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28384188/baroreflex-sensitivity-and-outcomes-following-coronary-surgery
#12
Marco Ranucci, Alberto Porta, Vlasta Bari, Valeria Pistuddi, Maria Teresa La Rovere
Postoperative atrial fibrillation, acute kidney dysfunction and low cardiac output following coronary surgery are associated with morbidity and mortality. The purpose of this study is to determine if the preoperative autonomic control is a determinant of these postoperative complications. This is a prospective cohort study on 150 adult patients undergoing surgical coronary revascularization with cardiopulmonary bypass. The patients received an autonomic control assessment after the induction of anesthesia. Baroreflex sensitivity was computed by spectral analysis and expressed as BRSαHF and BRSαLF for measure respectively in the high and low frequency domains...
2017: PloS One
https://www.readbyqxmd.com/read/28383399/poststroke-alterations-in-heart-rate-variability-during-orthostatic-challenge
#13
Joel Rodriguez, Andrew Philip Blaber, Markus Kneihsl, Irhad Trozic, Rebecca Ruedl, David A Green, James Broadbent, Da Xu, Andreas Rössler, Helmut Hinghofer-Szalkay, Franz Fazekas, Nandu Goswami
Older adults following recovery from ischemic stroke have a higher incidence of orthostatic hypotension, syncope, and fall risk, which may be related to impaired autonomic responses limiting the ability to maintain cerebral blood flow. Thus, we investigated cerebrovascular and cardiovascular regulation in 23 adults ≥55 years of age, 10 diagnosed with ischemic stroke, and 13 age-matched healthy controls when sitting at rest and upon standing to compare differences of autonomic variables at ∼7 months (218 ± 41 days) poststroke...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28377560/recent-advances-in-the-pathophysiology-of-arterial-hypertension-potential-implications-for-clinical-practice
#14
Dagmara Hering, Andrzej Trzebski, Krzysztof Narkiewicz
Hypertension remains a major and growing public health problem associated with the greatest global rate of cardiovascular morbidity and mortality. Although numerous factors contribute to poor control of blood pressure (BP) and to pseudoresistance (eg, unawareness, lifestyle habits, nonadherence to medication, insufficient treatment, drug‑induced hypertension, undiagnosed secondary causes), true resistant hypertension (RH) is reported in 10.1% of patients treated for elevated BP. While the mechanisms underlying RH remain complex and not entirely understood, sympathetic activation involved in the pathophysiology of hypertension, disease progression, and adverse complications is further augmented in patients with drug‑resistant hypertension...
March 1, 2017: Polish Archives of Internal Medicine
https://www.readbyqxmd.com/read/28376642/cardiovascular-sequel-of-neck-irradiation-in-head-and-neck-cancer-patients
#15
Manish Goyal, Pragya Shukla, Deepak Gupta, Shyam Bisht, Nar Singh Verma, Sunita Tiwari, Madan Lal Bhatt
PURPOSE: Introduction: The baroreflex is an important afferent mechanism controlling autonomic functions. As afferent nerves course through the neck, they are susceptible to damage by neck irradiation in the head and neck cancer patients. With increased survival of head and neck cancer patients because of improved therapy, the cardiovascular morbidity and mortality in them have become apparent and is of clinical concern. There are few case reports of baroreflex failure as a chronic sequel to neck irradiation...
April 5, 2017: International Journal of Radiation Biology
https://www.readbyqxmd.com/read/28376102/the-association-between-autonomic-dysfunction-inflammation-and-atherosclerosis-in-men-under-investigation-for-carotid-plaques
#16
Marcus A Ulleryd, Ulrica Prahl, Johannes Börsbo, Caroline Schmidt, Staffan Nilsson, Göran Bergström, Maria E Johansson
BACKGROUND: Autonomic dysfunction is a risk factor for cardiovascular disease (CVD), however, the exact mechanism linking autonomic dysfunction to cardiovascular disease is not known. In this study we hypothesized that autonomic dysfunction increases inflammation, which subsequently accelerates atherosclerosis. The aim of the current study was to investigate the association between autonomic tone, inflammation and atherosclerosis. METHODS: 124 men under investigation for carotid atherosclerosis were examined for autonomic function (heart rate variability; HRV and baroreflex sensitivity; BRS), inflammatory markers (white blood cell count; WBCC and C-reactive protein; CRP) and degree of carotid atherosclerosis...
2017: PloS One
https://www.readbyqxmd.com/read/28364029/intact-blood-pressure-but-not-sympathetic-responsiveness-to-sympathoexcitatory-stimuli-in-a-patient-with-unilateral-carotid-body-resection
#17
Kathryn F Larson, Jacqueline K Limberg, Sarah E Baker, Michael J Joyner, Timothy B Curry
Despite rapidly growing interest in the therapeutic resection of the carotid body (CB) chemoreceptors, few physiologic studies exist on the consequences of unilateral CB resection. We present a case of an otherwise healthy postmenopausal female who underwent unilateral CB resection for a paraganglioma. Approximately 4 years postoperatively, she underwent analysis of her sympathetic and hemodynamic responses to hypoxia, lower body negative pressure, cold pressor test (CPT), and ischemic hand grip exercise and postexercise ischemia (IHE/PEI)...
April 2017: Physiological Reports
https://www.readbyqxmd.com/read/28364017/recording-sympathetic-nerve-activity-in-conscious-humans-and-other-mammals-guidelines-and-the-road-to-standardization
#18
Emma C J Hart, Geoffrey A Head, Jason R Carter, Gunnar Wallin, Clive N May, Shereen M Hamza, John E Hall, Nisha Charkoudian, John W Osborn
Over the past several decades, studies of the sympathetic nervous system in humans, sheep, rabbits, rats and mice have substantially increased mechanistic understanding of cardiovascular function and dysfunction. Recently, interest in sympathetic neural mechanisms contributing to blood pressure control has grown, due in part to the development of devices or surgical procedures, which treat hypertension by manipulating sympathetic outflow. Studies in animal models have provided important insights into physiological and pathophysiological mechanisms, which are not accessible in human studies...
March 31, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28360882/vestibular-activation-habituates-the-vasovagal-response-in-the-rat
#19
Bernard Cohen, Giorgio P Martinelli, Yongqing Xiang, Theodore Raphan, Sergei B Yakushin
Vasovagal syncope is a significant medical problem without effective therapy, postulated to be related to a collapse of baroreflex function. While some studies have shown that repeated static tilts can block vasovagal syncope, this was not found in other studies. Using anesthetized, male Long-Evans rats that were highly susceptible to generation of vasovagal responses, we found that repeated activation of the vestibulosympathetic reflex (VSR) with ±2 and ±3 mA, 0.025 Hz sinusoidal galvanic vestibular stimulation (sGVS) caused incremental changes in blood pressure (BP) and heart rate (HR) that blocked further generation of vasovagal responses...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28346241/hemodynamic-responses-to-magnetic-stimulation-of-carotid-sinus-in-normotensive-rabbits
#20
Jun Zhang, Qinqin Cao, Rongrong Li, Jingze Hu, Jiafei Dai, Hao Zhang, Huaiming Wang, Fang Yang, Ruidong Ye, Xinfeng Liu, Gelin Xu
OBJECTIVES: Carotid baroreflex plays a crucial role in regulating arterial pressure. Based on this knowledge, electrical stimulation of carotid sinus was designed for treating resistant hypertension. However, the clinical implication of electrical stimulation of carotid sinus is largely restrained due to obvious invasiveness. This study aimed to evaluate the efficacy of magnetic stimulation of carotid sinus (MSCS), a noninvasive strategy, for lowering blood pressure in rabbits. METHODS: MSCS with graded intensities and frequencies were systematically attempted in normotensive rabbits...
March 24, 2017: Journal of Hypertension
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