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Transfusion Medicine (Oxford, England) Feb 2016Vasovagal reactions (VVRs) in blood donors have significant implications for the welfare of donors, donor retention and the management of donor sessions. We present a... (Meta-Analysis)
Meta-Analysis Review
Vasovagal reactions (VVRs) in blood donors have significant implications for the welfare of donors, donor retention and the management of donor sessions. We present a systematic review of interventions designed to prevent or reduce VVRs in blood donors. Electronic databases were searched for eligible randomised trials to March 2015. Data on study design and outcomes were extracted and pooled using random effects meta-analyses. Sixteen trials met the inclusion criteria: five trials (12 042 participants) of pre-donation water, eight trials (3500 participants) of applied muscle tension (AMT) and one trial each of AMT combined with water, caffeine, audio-visual distraction and/or social support. In donors receiving pre-donation water, the relative risk (RR) compared with controls for VVRs was 0·79 [95% confidence interval (CI) 0·70-0·89, P < 0·0001] and the mean difference (MD) in severity of VVRs measured with the Blood Donation Reactions Inventory (BDRI) score was -0·32 (95% CI -0·51 to -0·12, P < 0·0001). Excluding trials with a high risk of selection bias, the RR for VVRs was 0·70 (95% CI 0·45-1·11, P = 0·13). In donors who received AMT, there was no difference in the risk of chair recline in response to donor distress from controls (RR 0·76, 95% CI 0·53-1·10, P = 0·15), although the MD in BDRI score was -0·07 (95% CI -0·11 to -0·03, P = 0·0005). There was insufficient data to perform meta-analysis for other interventions. Current evidence on interventions to prevent or reduce VVRs in blood donors is indeed limited and does not provide strong support for the administration of pre-donation water or AMT during donation. Further large trials are required to reliably evaluate the effect of these and other interventions in the prevention of VVRs.
Topics: Blood Donors; Clinical Trials as Topic; Donor Selection; Female; Humans; Male; Risk Factors; Syncope, Vasovagal
PubMed: 27061617
DOI: 10.1111/tme.12275 -
Herz Feb 2022This study aimed to determine whether autonomic dysfunction in patients with vasovagal syncope with a positive tilt test may cause an alteration in atrial...
BACKGROUND
This study aimed to determine whether autonomic dysfunction in patients with vasovagal syncope with a positive tilt test may cause an alteration in atrial electromechanical properties and pose a risk for subsequent atrial arrhythmias, especially atrial fibrillation.
METHODS
The data of 27 patients with vasovagal syncope and a matched control group comprising 28 healthy individuals were compared. All patients underwent a tilt table test. Atrial electromechanical intervals (PA) were measured from the mitral lateral annulus, mitral septal annulus, and tricuspid annulus with tissue Doppler imaging. Left atrium volumes were measured with the disc method in apical four-chamber imaging.
RESULTS
Although atrial electromechanical intervals such as lateral PA, septal PA, and tricuspid PA durations were significantly longer (p = 0.009, p = 0.002, p = 0.011, respectively), interatrial, right intra-atrial, and left intra-atrial durations were similar in the vasovagal syncope group and the control group (p = 0.298, p = 0.388, p = 0.069, respectively). Left atrial volumes (maximum, minimum, and presystolic) were significantly increased in the vasovagal syncope group when compared with the control group (p = 0.001, p = 0.001, p = 0.007, respectively). There was no difference between vasovagal syncope types in terms of atrial electromechanical intervals.
CONCLUSION
Interatrial and intra-atrial intervals were similar in the vasovagal syncope group and the control group. However, an increase in atrial volumes and a prolongation of certain atrial electromechanical intervals were observed in patients with vasovagal syncope. These findings suggest an alteration in atrial electromechanics caused by autonomic dysfunction that can lead to subsequent atrial arrhythmias, especially atrial fibrillation.
Topics: Atrial Fibrillation; Echocardiography, Doppler; Heart Atria; Humans; Syncope, Vasovagal; Tilt-Table Test
PubMed: 33890135
DOI: 10.1007/s00059-021-05038-x -
Revista Portuguesa de Cardiologia Sep 2019Syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion and is one of the leading causes of emergency department admission. The... (Review)
Review
Syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion and is one of the leading causes of emergency department admission. The initial approach should focus on excluding non-syncopal causes for loss of consciousness and risk stratification for cardiac cause, in order to ensure an appropriate etiological investigation and therapeutic approach. Vasovagal syncope (VVS), the most common type of syncope, should be assumed once other causes are excluded. Pathophysiologically, the vasovagal reflex is the result of a paradoxical autonomic response, leading to hypotension and/or bradycardia. VVS has not been shown to affect mortality, but morbidity may be considerable in those with recurrent syncopal episodes. The management of VVS includes both non-pharmacological and pharmacological measures that act on various levels of the reflex arc that triggers the syncopal episode. However, most are of uncertain benefit given the scarcity of high-quality supporting evidence. Pacemaker therapy may be considered in recurrent refractory cardioinhibitory reflex syncope, for which it is currently considered a robust intervention, as noted in the European guidelines. Non-randomized and unblinded studies have shown a potential benefit of pacing in recurrent VVS, but double-blinded randomized controlled trials have not consistently demonstrated positive results. We performed a comprehensive review of the current literature and recent advances in cardiac pacing and pacing algorithms in VVS, and discuss the diagnostic and therapeutic approach to the complex patient with recurrent VVS and reduced quality of life.
Topics: Adult; Aged; Algorithms; Decision Support Systems, Clinical; Diagnosis, Differential; Female; Humans; Male; Middle Aged; Pacemaker, Artificial; Randomized Controlled Trials as Topic; Syncope, Vasovagal
PubMed: 31813672
DOI: 10.1016/j.repc.2018.11.007 -
Expert Opinion on Pharmacotherapy Mar 2015Syncope is an abrupt loss of consciousness in response to reduced perfusion to the brain. Neurocardiogenic or vasovagal syncope results from a complex neurologic reflex,... (Review)
Review
INTRODUCTION
Syncope is an abrupt loss of consciousness in response to reduced perfusion to the brain. Neurocardiogenic or vasovagal syncope results from a complex neurologic reflex, and treatments to prevent recurrence attempt to modulate aspects of that reflex.
AREAS COVERED
Pharmacologic treatments for vasovagal syncope address the syncope reflex in multiple ways. Fludrocortisone and sodium chloride increase systemic fluid volume. Midodrine, β blockers and norepinephrine transport inhibitors modulate the sympathetic nervous system. Other treatments for syncope modulate other neurotransmitters or affect heart rate. The most recent trials evaluating established and novel therapies are reviewed.
EXPERT OPINION
To reduce recurrence of vasovagal syncope, conservative measures are first line. If these fail to prevent recurrence, the most promising medical therapy includes midodrine. Randomized placebo-controlled data evaluating fludrocortisone, midodrine and β blockers in older patients are awaited. Because of the significance of the placebo effect in this condition, any treatment must be evaluated in a randomized double-blind placebo-controlled trial before being accepted as effective.
Topics: Clinical Trials as Topic; Heart Rate; Humans; Neurotransmitter Agents; Parasympathetic Nervous System; Practice Guidelines as Topic; Sympathetic Nervous System; Syncope, Vasovagal; Water-Electrolyte Balance
PubMed: 25534874
DOI: 10.1517/14656566.2015.996129 -
The New Zealand Medical Journal Jul 2022In adults, the onset of vasovagal syncope is often unexplained. We wished to explore if moderate weight loss triggers the onset of vasovagal syncope (VVS).
AIM
In adults, the onset of vasovagal syncope is often unexplained. We wished to explore if moderate weight loss triggers the onset of vasovagal syncope (VVS).
METHODS
A retrospective case-control study comparing demographic characteristic, syncope symptoms, and tilt-table results of patients who had recently lost weight (n=57), with randomly selected weight-stable patients (n=73), and controls, patients without syncope (n=24).
RESULTS
VVS was diagnosed in 480 out of 1,209 clinic patients of whom 57 (11.9%) reported moderate weight loss. The mean (SD) reported weight loss was 11.5 (7) kg over 18.7 (13) months. Age and gender did not differ between groups: in the weight loss, weight stable, and control groups the mean age was 44.8, 45.2, and 44 years respectively; and proportion female 60%, 64%, and 54%. Body weight, mass index and calculated blood volume at presentation were also similar in the different groups. Weight loss preceded or coincided the onset of syncope in 80% of patients; the length of time over which weight loss occurred was associated with the length of time of syncope symptoms, product moment correlation coefficient 0.45, p=0.001. Syncope in childhood and teenage years was less frequent in the weight loss group compared to the weight stable group: 37% vs 53%. After 10 minutes of head-up tilt, stroke volume was preserved in both syncope groups compared to controls; percentage of baseline mean (SD) in the weight loss, weight stable, and control groups: 71(18), 69(10), and 61 (11) respectively; despite lower blood pressure in the weight loss groups with mean (SD) 90 (14) mmHg, 93 (13) and 103 (14) respectively.
CONCLUSIONS
Some patients have onset of VVS within a few months of weight loss resulting in earlier presentation to clinic. The physiological mechanism for this is uncertain.
Topics: Adult; Case-Control Studies; Female; Humans; Male; Middle Aged; New Zealand; Retrospective Studies; Syncope; Syncope, Vasovagal; Tilt-Table Test; Weight Loss
PubMed: 35834829
DOI: 10.26635/6965.5521 -
High Blood Pressure & Cardiovascular... Aug 2019Syncope is a temporary loss of consciousness due to transient global cerebral hypoperfusion. Reflex syncope is the most frequent, representing 21% of all types of... (Review)
Review
Syncope is a temporary loss of consciousness due to transient global cerebral hypoperfusion. Reflex syncope is the most frequent, representing 21% of all types of syncopal events, and includes: (a) the vasovagal syncope (classical type); (b) the situational syncope; (c) the carotid sinus syncope and (d) non-classical forms. An accurate anamnesis and physical examination are fundamental for the diagnosis. Although limited evidence is available regarding the efficacy of some treatments, a number of these can be successfully used in the clinical practice. It is, however, important to personalize the therapeutic approach in order to achieve an efficient reduction or suppression of syncopal episodes. Patients should be reassured about the benignity of these events and the possibility of reducing their frequency over time. They should be also educated on how to recognize and abort incoming syncopal episodes. Patients may be advised to increase their introit in water and salt, as well as to reduce vasoactive medications, if no contraindications exist. Orthostatic training may be beneficial but only in very motivated young patients capable of strictly adhering to the exercise plan. So far, any proposed pharmacological treatment has demonstrated very limited efficacy and, therefore, it should be tried in case of failure of non-pharmacological approaches. Pacemaker implantation is clearly indicated in patients with documented cardioinhibitory syncope in the absence of a vasodepressor component, which can compromise their quality of life. Despite the American and European guidelines for the treatment of syncope are similar, still some differences can be denoted. Aim of this study is to evaluate the management of patients with recurrent syncopal episodes focusing on pharmacological and non-pharmacological approaches.
Topics: Blood Pressure; Cerebrovascular Circulation; Clinical Decision-Making; Consciousness; Humans; Practice Guidelines as Topic; Recurrence; Risk Factors; Syncope, Vasovagal; Treatment Outcome
PubMed: 31297720
DOI: 10.1007/s40292-019-00327-3 -
Brazilian Journal of Cardiovascular... Feb 2021It is challenging to diagnose syncope in patients with pacemakers. Because these patients have increased morbidity and mortality risks, they require immediate attention...
INTRODUCTION
It is challenging to diagnose syncope in patients with pacemakers. Because these patients have increased morbidity and mortality risks, they require immediate attention to determine the causes in order to provide appropriate treatment. This study aimed to investigate the causes and predictive factors of syncope as well as the methods used to diagnose syncope in cardiac pacemaker patients.
METHODS
Patients with pacemakers implanted owing to sinus node disease or atrioventricular block were evaluated with standardized questionnaires, endocavitary electrograms, and other tests based on the suspected causes of syncope. Mann- Whitney U tests were used to analyze continuous variables and Chi-squared or Fisher's exact tests were used for categorical variables. Logistic regression was used for multivariate analyses. Statistical significance was P<0.05.
RESULTS
The study included 95 patients with pacemakers: 47 experienced syncope in the last 12 months and 48 did not. Of the 100 documented episodes of syncope, 48.9% were vasovagal syncopes, 17% had cardiac-related causes, 10.6% had unknown causes, and 8.5% had pacemaker failure. The multivariate analysis showed that a New York Heart Association (NYHA) Functional Class II was a significant factor for developing syncope (P<0.01).
CONCLUSION
While the most common type of syncope in pacemaker patients was neurally mediated, it is important to perform detailed evaluations in this population as the causes of syncope can be life-threatening. The best diagnostic methods were stored electrogram analysis and the tilt table test. NYHA Functional Class II patients were found to have a higher risk for syncope.
Topics: Atrioventricular Block; Humans; Pacemaker, Artificial; Syncope; Syncope, Vasovagal; Tilt-Table Test
PubMed: 33594860
DOI: 10.21470/1678-9741-2020-0076 -
Scientific Reports Jun 2023Around one-third of adults are scared of needles, which can result in adverse emotional and physical responses such as dizziness and fainting (e.g. vasovagal reactions;...
Around one-third of adults are scared of needles, which can result in adverse emotional and physical responses such as dizziness and fainting (e.g. vasovagal reactions; VVR) and consequently, avoidance of healthcare, treatments, and immunizations. Unfortunately, most people are not aware of vasovagal reactions until they escalate, at which time it is too late to intervene. This study aims to investigate whether facial temperature profiles measured in the waiting room, prior to a blood donation, can be used to classify who will and will not experience VVR during the donation. Average temperature profiles from six facial regions were extracted from pre-donation recordings of 193 blood donors, and machine learning was used to classify whether a donor would experience low or high levels of VVR during the donation. An XGBoost classifier was able to classify vasovagal groups from an adverse reaction during a blood donation based on this early facial temperature data, with a sensitivity of 0.87, specificity of 0.84, F1 score of 0.86, and PR-AUC of 0.93. Temperature fluctuations in the area under the nose, chin and forehead have the highest predictive value. This study is the first to demonstrate that it is possible to classify vasovagal responses during a blood donation using temperature profiles.
Topics: Adult; Humans; Needles; Temperature; Syncope, Vasovagal; Syncope; Vertigo
PubMed: 37316637
DOI: 10.1038/s41598-023-36207-z -
International Journal of Molecular... Sep 2021Syncope, defined as a transient loss of consciousness caused by transient global cerebral hypoperfusion, affects 30-40% of humans during their lifetime. Vasovagal... (Review)
Review
Syncope, defined as a transient loss of consciousness caused by transient global cerebral hypoperfusion, affects 30-40% of humans during their lifetime. Vasovagal syncope (VVS) is the most common cause of syncope, the etiology of which is still unclear. This review summarizes data on the genetics of VVS, describing the inheritance pattern of the disorder, candidate gene association studies and genome-wide studies. According to this evidence, VVS is a complex disorder, which can be caused by the interplay between genetic factors, whose contribution varies from monogenic Mendelian inheritance to polygenic inherited predisposition, and external factors affecting the monogenic (resulting in incomplete penetrance) and polygenic syncope types.
Topics: Genetic Predisposition to Disease; Humans; Inheritance Patterns; Multifactorial Inheritance; Syncope, Vasovagal
PubMed: 34638656
DOI: 10.3390/ijms221910316 -
Autonomic Neuroscience : Basic &... Jan 2022Syncope in the elderly patient is a common presentation and the most common causes are usually non-cardiac. Older adults however are more challenging dilemmas as their...
Syncope in the elderly patient is a common presentation and the most common causes are usually non-cardiac. Older adults however are more challenging dilemmas as their presentation is complicated by co-morbidities, mainly cardiovascular and neurodegenerative disorders. Frailty and cognitive impairment add to the ambiguity of the presentation, and polypharmacy is often a major modifiable contributing factor. Vasovagal syncope is a common presentation throughout life even as we age. It has a favorable prognosis and conservative management usually suffices. Vasovagal syncope in this population may be misdiagnosed as accidental falls and is frequently associated with injury, as is carotid sinus syndrome. The initial approach to these patients entails a detailed history and physical examination including a comprehensive medication history, orthostatic vital signs, and a 12-lead electrocardiogram. Further cardiac and neuroimaging rarely helps, unless directed by specific clinical findings. Head-up tilt testing and carotid sinus massage retain their diagnostic accuracy and safety in the elderly, and implantable loop recorders provide important information in many elderly patients with unexplained falls and syncope. The starting point in management of this population with non-cardiac syncope is attempting to withdraw unnecessary vasoactive and psychotropic medications. Non-pharmacologic and pharmacologic therapy for syncope in the elderly has limited efficacy and safety concerns. In selected patients, pacemaker therapy might offer symptomatic relief despite lack of efficacy when vasodepression is prominent. An approach focused on primary care with targeted specialist referral seems a safe and effective strategy.
Topics: Aged; Aging; Carotid Sinus; Humans; Syncope; Syncope, Vasovagal; Tilt-Table Test
PubMed: 34856496
DOI: 10.1016/j.autneu.2021.102919