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neurally mediated hypotension

Carlos Javier Shiraishi Zapata
I report a case of hypotension and bradycardia before spinal anesthesia in a pregnant woman with mild to moderate hypertension treated with nifedipine and methyldopa, scheduled for an elective cesarean delivery. She had the history of neurally-mediated syncopes. Two main factors (increased vagal tone and adverse effects of antihypertensive drugs) could explain the hypotension and bradycardia before spinal anesthesia. Monitoring allowed recognizing the problem and corrected it. Thus, it was avoided a disaster in anesthesia, as hemodynamic changes after spinal anesthesia, they would have joined to previous hypotension and bradycardia, which would have caused even a cardiac arrest...
September 26, 2016: Revista Brasileira de Anestesiologia
Peder S Olofsson, Benjamin E Steinberg, Roozbeh Sobbi, Maureen A Cox, Mohamed N Ahmed, Michaela Oswald, Ferenc Szekeres, William M Hanes, Andrea Introini, Shu Fang Liu, Nichol E Holodick, Thomas L Rothstein, Cecilia Lövdahl, Sangeeta S Chavan, Huan Yang, Valentin A Pavlov, Kristina Broliden, Ulf Andersson, Betty Diamond, Edmund J Miller, Anders Arner, Peter K Gregersen, Peter H Backx, Tak W Mak, Kevin J Tracey
Blood pressure regulation is known to be maintained by a neuro-endocrine circuit, but whether immune cells contribute to blood pressure homeostasis has not been determined. We previously showed that CD4(+) T lymphocytes that express choline acetyltransferase (ChAT), which catalyzes the synthesis of the vasorelaxant acetylcholine, relay neural signals. Here we show that these CD4(+)CD44(hi)CD62L(lo) T helper cells by gene expression are a distinct T-cell population defined by ChAT (CD4 TChAT). Mice lacking ChAT expression in CD4(+) cells have elevated arterial blood pressure, compared to littermate controls...
October 2016: Nature Biotechnology
Sandor Viski, Miklos Orosz, Katalin Reka Czuriga-Kovacs, Maria Tunde Magyar, Laszlo Csiba, Laszlo Olah
BACKGROUND: Alcohol is a known triggering factor for orthostatic dysfunction, increasing the risk of neurally-mediated syncope. Since orthostatic tolerance may be affected by both systemic and cerebral hemodynamic changes, our aim was to investigate the acute effects of alcohol on cerebral vasoreactivity measured during the head-up tilt (HUT) test in 20 healthy subjects. METHODS: Mean arterial blood pressure (mBP), heart rate, and flow parameters in both middle cerebral arteries (MCAs) were continuously recorded in the supine and during a 10-minute HUT positions before and after alcohol intake...
September 15, 2016: Journal of the Neurological Sciences
Peter Novak
Objective. The head-up tilt test is widely used for evaluation of orthostatic intolerance. Although orthostatic symptoms usually reflect cerebral hypoperfusion, the cerebral blood flow velocity (CBFv) profile in orthostatic syndromes is not well described. This study evaluated CBFv and cardiovascular patterns associated with the tilt test in common orthostatic syndromes. Methods. This retrospective study analyzed the tilt test of patients with history of orthostatic intolerance. The following signals were recorded: ECG, blood pressure, CBFv using transcranial Doppler, respiratory signals, and end tidal CO2...
2016: Neuroscience Journal
Geoffrey L Heyer, Dara V F Albert, Amanda Weber, Satyanarayana Gedela, Jorge Vidaurre
We sought to characterize the clinical features of tilt-induced psychogenic nonsyncopal collapse (PNSC) from a cohort of young patients and to compare the semiologies between PNSC and EEG-confirmed psychogenic nonepileptic seizures (PNES). A PNSC diagnosis was made if a clinical event occurred during tilt-table testing that the patient regarded as fainting, but neither hypotension nor EEG changes were present. A diagnosis of PNSC was made in 17.6% of all patients referred during the 15-month study period. Cohorts with psychogenic nonsyncopal collapse (n=40) and PNES (n=40) did not differ in age (15...
September 2016: Epilepsy & Behavior: E&B
Katarzyna Kaczyńska, Monika Jampolska, Małgorzata Szereda-Przestaszewska
Neurokinin A (NKA) is a peptide neurotransmitter that participates in the regulation of breathing and the cardiovascular system. The purpose of the current study was to determine the cardiorespiratory pattern exerted by the systemic injection of NKA, to look at the contribution of neurokinin NK1 and NK2 receptors, and to establish the engagement of the vagal pathway in mediation of these responses. The effects of intravenous injections of NKA (50 μg/kg) were studied in anaesthetized, spontaneously breathing rats in the following experimental schemes: in neurally intact rats; and vagotomized at either midcervical or supranodosal level...
September 2016: Clinical and Experimental Pharmacology & Physiology
Donglei Liao, Yi Xu, Runmei Zou, Lijia Wu, Xuemei Luo, Fang Li, Ping Lin, Xiuying Wang, Zhenwu Xie, Cheng Wang
OBJECTIVE: To explore the circadian rhythm of neurally mediated syncope (NMS). METHODS: 411 patients with NMS (165 males and 246 females aged from 3 to 68years) were included in the study. All subjects underwent head-up tilt test (HUTT) and were carefully asked about the number of syncopal attacks and the periods (morning 06:00am-12:00am, afternoon 12:00am-18:00pm, evening 18:00pm-24:00pm, night 00:00am-06:00am) in which episodes occurred in. RESULTS: (1) Syncopal attacks of all patients tended to occur in the morning (P=0...
July 15, 2016: International Journal of Cardiology
Daniele C B Aprile, Bruna Oneda, Josiane L Gusmão, Luiz A R Costa, Claudia L M Forjaz, Decio Mion, Tais Tinucci
BACKGROUND: This study aimed at evaluating the after effects of a single bout of aerobic exercise on muscle sympathetic nerve activity (MSNA), peripheral vascular resistance and blood pressure (BP) in stages 2-3 chronic kidney disease (CKD) patients. We hypothesized that CKD patients present a greater decline in these variables after the exercise than healthy individuals. METHODS: Nine patients with stages 2-3 CKD (50 ± 8 years) and 12 healthy volunteers (50 ± 5 years) underwent 2 sessions, conducted in a random order: exercise (45 min, cycle ergometer, 50% of peak oxygen uptake) and rest (seated, 45 min)...
2016: American Journal of Nephrology
Abdel-Hadi Rami, Muresan Lucian, Pop Dana, Zdrenghea Dumitru
BACKGROUND: Syncope carries a poor prognosis among patients with dilated cardiomyopathy (DCM). OBJECTIVES: To assess the prevalence, describe the underlying mechanisms and to identify risk factors for syncope in patients with DCM. METHODS: One thousand six hundred and ten medical files of 897 patients with a diagnosis of DCM were reviewed. Patients with syncope were identified and their clinical and paraclinical profiles were compared to an equal number of age- and sex-matched patients with DCM without syncope...
April 2016: Indian Heart Journal
Christian Haarmark, Jørgen K Kanters, Jesper Mehlsen
The diagnosis of recurrent syncope in patients with pacemakers (PM) is quite challenging and the etiology of syncope is often multifactorial. To portray the mechanism of syncope in PM patients, we report the results of head-up tilt table testing (HUT) in a series of patients with PM, originally implanted for reasons other than neurally mediated syncope, referred due to syncope or pre-syncope (aborted syncope, vertigo, suspected orthostatic hypotension). Forty-one patients with PM undergoing a HUT in our syncope unit between January 1st, 2007 and December 31st 2011 were included...
July 2015: Indian Pacing and Electrophysiology Journal
Helder Veras Ribeiro-Filho, Camila Meirelles de Souza Silva, Rodrigo JoséBezerra de Siqueira, Saad Lahlou, Armênio Aguiar dos Santos, Pedro Jorge Caldas Magalhães
β-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, β-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that β-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects. In anesthetized rats, intravenous injection of β-citronellol caused biphasic hypotension, bradycardia and apnea. Bilateral vagotomy, perivagal capsaicin treatment or injection into the left ventricle abolished first rapid phase (named P1) but not delayed phase P2 of the β-citronellol effects...
March 15, 2016: European Journal of Pharmacology
C Busnardo, C C Crestani, A Fassini, L B M Resstel, F M A Corrêa
Here we report the involvement of N-Methyl-d-Aspartate (NMDA) and non-NMDA glutamate receptors from the paraventricular nucleus of the hypothalamus (PVN) in the mediation of cardiovascular changes observed during hemorrhage and post-bleeding periods. In addition, the present study provides further evidence of the involvement of circulating vasopressin and cardiac sympathetic activity in cardiovascular responses to hemorrhage. Systemic treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50 μg/kg, i...
April 21, 2016: Neuroscience
Jeffrey P Moak, Robin R Fabian, Lindsay C Clarke, Sridhar Hanumanthaiah, John Desbiens, Anil Darbari
OBJECTIVES: Gastrointestinal (GI) symptoms of nausea, vomiting, and abdominal pain are common in patients with orthostatic intolerance (OI), including neurally mediated hypotension (NMH) and postural orthostatic tachycardia syndrome (POTS). Autonomic dysregulation is considered the underlying pathophysiology behind the cardiovascular symptoms of POTS. Because the autonomic nervous system also regulates GI motility, we hypothesized that patients with POTS and GI symptoms will have evidence of autonomic dysmotility of the upper GI tract...
September 2016: Journal of Pediatric Gastroenterology and Nutrition
N A B Ntusi, C B I Coccia, B J Cupido, A Chin
Syncope, defined as a brief loss of consciousness due to an abrupt fall in cerebral perfusion, remains a frequent reason for medical presentation. The goals of the clinical assessment of a patient with syncope are twofold: (i) to identify the precise cause in order to implement a mechanism-specific and effective therapeutic strategy; and (ii) to quantify the risk to the patient, which depends on the underlying disease,rather than the mechanism of the syncope. Hence, a structured approach to the patient with syncope is required...
August 2015: South African Medical Journal, Suid-Afrikaanse Tydskrif Vir Geneeskunde
Jeffrey P Moak, Derek Leong, Robin Fabian, Vicki Freedenberg, Elizabeth Jarosz, Carol Toney, Sridhar Hanumanthaiah, Anil Darbari
Orthostatic intolerance (OI) is common in teenagers (T) and young adults (A). Despite treatment with oral fluids, medication, and exercise, a significant number have symptoms from multiple organ systems and suffer low quality of life (QOL). Previous studies showed that acute intravenous (IV) hydration (IH) could help restore orthostatic tolerance; however, no data are available about the intermediate-term effects of IH. We therefore studied the efficacy of IH to improve QOL and manage medication-refractory OI patients...
February 2016: Pediatric Cardiology
Iain G Matthews, Isabel A E Tresham, Steve W Parry
Syncope in the older person carries a high morbidity, mortality, and health economic burden. While neurally mediated disorders and orthostatic hypotension account for the majority of syncopal episodes in this age group, around a third of causes are cardiac, predominantly arrhythmic. Clinicians need to be aware of the management of potential comorbid issues such as osteoporosis and cognitive impairment and if not in a position to act on them, ensure that appropriate specialist help is sought. Further work is needed to understand the pathophysiology and hence the management of syncope in the older patient, with ongoing studies helping to tease out some of the treatment controversies...
August 2015: Cardiology Clinics
Gino Nardocci, Aldo Martin, Sebastián Abarzúa, Jorge Rodríguez, Felipe Simon, Edison P Reyes, Claudio Acuña-Castillo, Cristina Navarro, Paula P Cortes, Ricardo Fernández
Sepsis progresses to multiple organ dysfunction (MOD) due to the uncontrolled release of inflammatory mediators. Carotid chemo/baro-receptors could play a protective role during sepsis. In anesthetized male rats, we measured cardiorespiratory variables and plasma TNF-α, glucocorticoids, epinephrine, and MOD marker levels 90min after lipopolysaccharide (LPS) administration in control (SHAM surgery) and bilateral carotid chemo/baro-denervated (BCN) rats. BCN prior to LPS blunted the tachypneic response and enhanced tachycardia and hypotension...
January 15, 2015: Journal of Neuroimmunology
Jens Muehlsteff, Kiran Dellimore, Vincent Aarts, Christoph Brinkmeyer, Christian Eickholt, Malte Kelm, Christian Meyer
Neurally mediated syncope (NMS) is a disorder of the autonomic regulation of postural tone, which is characterized by hypotension and/or bradycardia, resulting in cerebral hypo-perfusion and finally in a sudden loss of consciousness. Prediction of an impending NMS requires detection of pulse presence to derive heart rate (HR) as well as to assess the pulse strength (PS) related to systolic blood pressure (SBP) preferably from a single body location only. This paper analyses the basic feasibility of using a single accelerometer positioned above the common carotid artery to assess pulse strength and pulse rate towards NMS prediction...
2014: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Rose M F L da Silva
Syncope is a common medical problem, with a frequency between 15% and 39%. In the general population, the annual number episodes are 18.1-39.7 per 1000 patients, with similar incidence between genders. The first report of the incidence of syncope is 6.2 per 1000 person-years. However, there is a significant increase in the incidence of syncope after 70 years of age with rate annual 19.5 per thousand individuals after 80 years. It presents a recurrence rate of 35% and 29% of physical injury. Among the causes of syncope, the mediated neural reflex, known as neurocardiogenic or vasovagal syncope, is the most frequent...
2014: Frontiers in Physiology
Michele Brignole
Neurally-mediated syncope has a broad clinical spectrum which ranges from typical vasovagal syncope on one hand, to those situations in which reflex syncope occurs with uncertain, or even apparently absent, triggers or prodromes, on the other hand. Overlap of clinical features is frequent in clinical practice and makes any classification difficult to apply when selecting patients for cardiac pacing. Typically, the reflex is both hypotensive and cardio-inhibitory. The rationale for efficacy of cardiac pacing is that the cardio-inhibitory reflex is dominant, since there is no role for pacing in preventing vasodilatation and hypotension...
2014: Cardiology Journal
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