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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 -
Current Opinion in Cardiology Jan 2009The absence of a satisfactory comprehensive theory for vasovagal syncope has prompted attention towards a possible genetic origin. There are several features of this... (Review)
Review
PURPOSE OF REVIEW
The absence of a satisfactory comprehensive theory for vasovagal syncope has prompted attention towards a possible genetic origin. There are several features of this trait that suggest a genetic origin. The purposes of this review are to present a rationale for considering a genetic origin and critically summarize recent findings.
RECENT FINDINGS
Key characteristics that suggest a genetic origin are incomplete effect in the population, a persistent clinical phenotype, and the absence of obvious infectious or autoimmune causes. There are familial pedigrees of vasovagal syncope, and statistical analyses of the impact of family history on the likelihood of an individual fainting that suggest an autosomal dominant transmission with incomplete penetrance. There is also evidence of sex-specific penetrance. Early candidate gene studies point towards involvement of sympathetic signal transduction in the physiologic cascade.
SUMMARY
Several epidemiologic characteristics of vasovagal syncope suggest that it may have a genetic origin.
Topics: Genetic Predisposition to Disease; Humans; Inheritance Patterns; Pedigree; Polymorphism, Genetic; Syncope, Vasovagal
PubMed: 19102038
DOI: 10.1097/hco.0b013e32831ba05f -
Archives of Dermatological Research Sep 2022Although vasovagal syncopal episodes (VSE) are a well-known complication of dermatologic surgery, there are currently no studies that report an incidence of VSE in Mohs...
Although vasovagal syncopal episodes (VSE) are a well-known complication of dermatologic surgery, there are currently no studies that report an incidence of VSE in Mohs surgery specifically. This study aims to provide data on the incidence of VSE in Mohs surgery by reviewing VSE incident reports from a private, community-based, outpatient Mohs surgery clinic. We report an incidence of VSE of 0.09% in Mohs surgery. This study offers the first data on the incidence of VSE during Mohs surgery and suggests that the incidence of VSE in Mohs surgery may be lower than what has been quoted as the reference standard for dermatologic surgery.
Topics: Humans; Incidence; Mohs Surgery; Syncope, Vasovagal; Tilt-Table Test
PubMed: 33710391
DOI: 10.1007/s00403-021-02215-0 -
Hellenic Journal of Cardiology : HJC =... 2008
Review
Topics: Age Factors; Autonomic Nervous System Diseases; Diagnosis, Differential; Humans; Risk Factors; Syncope, Vasovagal
PubMed: 18459461
DOI: No ID Found -
Anesthesia Progress Jun 2023
Topics: Humans; Anesthesia, Local; Anaphylaxis; Hypotension; Syncope, Vasovagal
PubMed: 37379085
DOI: 10.2344/anpr-70-03-02 -
Europace : European Pacing,... Sep 2005Vasovagal syncope (VVS) is a common clinical problem characterized by transient episodes of loss of consciousness due to abnormal autonomic activity. This paper...
Vasovagal syncope (VVS) is a common clinical problem characterized by transient episodes of loss of consciousness due to abnormal autonomic activity. This paper describes two groups of monozygotic twins, from different families, affected by VVS and a family with several members with this condition. Their clinical characteristics, haemodynamic response to tilt, treatment, and outcome are described.
Topics: Adult; Female; Humans; Male; Middle Aged; Pedigree; Syncope, Vasovagal; Tilt-Table Test; Twins, Monozygotic
PubMed: 16087112
DOI: 10.1016/j.eupc.2005.05.004 -
Heart Rhythm Mar 2016The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR ×... (Review)
Review
The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR × CO, hypotension can result from a decrease in systemic vascular resistance (SVR), cardiac output (CO), or both. It is important to understand that when blood pressure (BP) is falling, SVR and CO do not change reciprocally as they do in the steady state. In 1932, Lewis, assuming that decreased SVR alone accounted for hypotension, defined "the vasovagal response" along pathophysiologic lines to denote the association of vasodilation with vagal-induced bradycardia in simple faint. Studies performed by Barcroft and Sharpey-Schafer between 1940 and 1950 used volume-based plethysmography to demonstrate major forearm vasodilation during extreme hypotension and concluded that the main mechanism for hypotension was vasodilation. Plethysmographic measurements were intermittent and not frequent enough to capture rapid changes in blood flow during progressive hypotension. However, later investigations by Weissler, Murray, and Stevens performed between 1950 and 1970 used invasive beat-to-beat BP measurements and more frequent measurements of CO using the Fick principle. They demonstrated that CO significantly fell before syncope, and little vasodilation occurred until very late in the vasovagal reaction Thus, since the 1970s, decreasing cardiac output rather than vasodilation has been regarded as the principal mechanism for the hypotension of vasovagal syncope.
Topics: Cardiac Output; Cardiology; Humans; Periodicals as Topic; Syncope, Vasovagal; Vasodilation
PubMed: 26598322
DOI: 10.1016/j.hrthm.2015.11.023 -
Heart Rhythm May 2020
Topics: Humans; Pacemaker, Artificial; Patient Selection; Syncope, Vasovagal; Tilt-Table Test
PubMed: 32113895
DOI: 10.1016/j.hrthm.2020.02.026 -
Transfusion Medicine (Oxford, England) Apr 2019This narrative review examines current research on risk factors, prevention methods and management strategies for vasovagal reactions (VVRs) that occur during or as a... (Review)
Review
This narrative review examines current research on risk factors, prevention methods and management strategies for vasovagal reactions (VVRs) that occur during or as a result of blood donation. VVRs are important to blood collection agencies (BCAs) as they negatively impact the number of completed collections, perceptions of the safety of blood donation and rates of donor return. There has been significant progress in understanding and preventing VVRs in blood donation in recent years, with a multitude of risk factors identified. This has resulted in many BCAs implementing evidence-based strategies, such as donor age and weight restrictions. However, the profile of our most vulnerable donors and features of the donation setting that may protect these donors from experiencing a VVR have not been identified. Furthermore, an increased number of trials of physiological and psychological prevention interventions to reduce both immediate and delayed VVRs have been reported. However, a lack of methodological consistency in operationalising interventions to reduce or prevent VVRs means that the identification of effective VVR prevention strategies remains a challenge for practitioners. Furthermore, research is still required to determine how to successfully implement prevention and management strategies into standard operating procedures within collection centres. Finally, research in the management and mitigation of the effect of VVRs is currently only suggestive of what should be done to care for the donor who reacts and how to empower those donors to return. Collectively, research into these aspects of VVRs will provide support to donors and BCAs and improve the safety of blood donation.
Topics: Blood Donors; Female; Humans; Male; Risk Factors; Syncope, Vasovagal
PubMed: 29148259
DOI: 10.1111/tme.12488 -
Clinical Autonomic Research : Official... Apr 2005Vasovagal syncope, although often seen as a disease, is the result of a neurophysiological reflex which can be induced in most healthy people after a 30 % reduction in... (Review)
Review
Vasovagal syncope, although often seen as a disease, is the result of a neurophysiological reflex which can be induced in most healthy people after a 30 % reduction in blood volume either by venous pooling or by hemorrhage. Studies in mammals showed that the activation of certain brainstem nuclei including the caudal midline medulla is responsible for hypotension and bradycardia following central hypovolemia. The hypothesis is presented that vasovagal fainting developed during the evolution in order to support hemostasis. Bleeding animals with a central mechanism for the initiation of hypotension had presumably a better chance for blood clot formation and hemostasis than animals with normal blood pressure. In the context of this hypothesis, vasavagal fainting with blood or injury displaying stimuli can be understood as an early attempt to support hemostasis before the development of larger blood losses.
Topics: Biological Evolution; Emotions; Hemorrhage; Hemostasis; Humans; Syncope; Syncope, Vasovagal; Tilt-Table Test
PubMed: 15834770
DOI: 10.1007/s10286-005-0244-0