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Expert Review of Cardiovascular Therapy Dec 2014Vasovagal syncope (VVS) is a common form of fainting. The pathophysiology of VVS is complex and involves changes in the autonomic and vascular tone, resulting in reflex...
Vasovagal syncope (VVS) is a common form of fainting. The pathophysiology of VVS is complex and involves changes in the autonomic and vascular tone, resulting in reflex bradycardia with marked hypotension. Paradoxical peripheral vasodilation caused by endothelial dysfunction may also play a key role in inappropriate hypotension during VVS. Endothelial hyperactivity due to up regulation of nitric oxide synthase leads to profound vasodilation, much stronger than vasodilation caused by adrenergic stimulation in response to orthostatic stress alone. Studies have reported significantly higher flow-mediated dilation and higher plasma nitric oxide concentration in people with vasovagal syndrome. Patients with VVS showed decreased vasoconstrictive agent endothelin-1 levels during orthostatic stress. Coagulation and fibrinolysis activity also play important roles in endothelial function in syncopal patients. The response of the endothelium to orthostatic stress is similar to the reaction to haemorrhagic stress and is likely to be a remnant from the evolutionary adaptation of primates.
Topics: Autonomic Nervous System; Endothelium; Humans; Hypotension, Orthostatic; Stress, Physiological; Syncope, Vasovagal; Vasodilation
PubMed: 25410020
DOI: 10.1586/14779072.2014.982095 -
Magnetic Resonance Imaging Clinics of... Nov 2017Adverse reactions to iodinated and gadolinium-based contrast agents occur at an incidence of less than 1%. Although the exact pathophysiologic mechanisms are not... (Review)
Review
Adverse reactions to iodinated and gadolinium-based contrast agents occur at an incidence of less than 1%. Although the exact pathophysiologic mechanisms are not completely understood, the treatment regimens are well accepted. Skin testing may be helpful in patients with a history of severe allergiclike reaction to aid in the selection of alternative contrast agents. Premedication should only be used for a history of allergiclike reaction. Imaging team members should be familiar with signs and symptoms of contrast reactions to allow for prompt assessment and treatment. A plan of action should be in place for contrast reactions and rehearsed regularly.
Topics: Adrenal Cortex Hormones; Antihypertensive Agents; Contrast Media; Diuretics; Drug Hypersensitivity; Fluid Therapy; Histamine Antagonists; Humans; Hypertension; Nitroglycerin; Oxygen Inhalation Therapy; Pulmonary Edema; Risk Factors; Syncope, Vasovagal; Vasodilator Agents
PubMed: 28964463
DOI: 10.1016/j.mric.2017.06.008 -
Clinical Cardiology Jul 2023Vasovagal syncope (VVS) is the most prevalent type of syncope and its management includes pharmacologic and non-pharmacologic interventions. Recently, studies have... (Meta-Analysis)
Meta-Analysis Review
Vasovagal syncope (VVS) is the most prevalent type of syncope and its management includes pharmacologic and non-pharmacologic interventions. Recently, studies have investigated vitamin D levels in VVS patients. In this systematic review and meta-analysis, we aim to review these studies to find possible associations between vitamin D deficiency and vitamin D levels with VVS. International databases including Scopus, Web of Science, PubMed, and Embase were searched with keywords related to "vasovagal syncope" and "vitamin D." Studies were screened and the data were extracted from them. Random-effect meta-analysis was conducted to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) for vitamin D levels in comparison to VVS patients and controls. Also, VVS occurrence was measured and the odds ratio (OR) and 95% CI were calculated for comparison of vitamin D deficient cases and nondeficient individuals. Six studies were included with 954 cases investigated. Meta-analysis showed that patients with VVS had significantly lower vitamin D serum levels in comparison to non-VVS cases (SMD -1.05, 95% CI -1.54 to -0.57, p-value < .01). Moreover, VVS occurrence was higher in vitamin D-deficient individuals (OR 5.43, 95% CI 2.40 to 12.27, p-value < .01). Our findings which show lower vitamin D levels in VVS patients can have clinical implications in order for clinicians to pay attention to this when approaching VVS. Further randomized controlled trials are certainly warranted to assess the role of vitamin D supplementation in individuals with VVS.
Topics: Humans; Tilt-Table Test; Syncope, Vasovagal; Syncope; Vitamin D Deficiency; Vitamin D
PubMed: 37226313
DOI: 10.1002/clc.24035 -
Autonomic Neuroscience : Basic &... Sep 2014Vasovagal syncope (VVS) is the most frequent type of syncope and affects about 25% of the population. The role of genetic factors in VVS has long been debated. In this... (Review)
Review
INTRODUCTION
Vasovagal syncope (VVS) is the most frequent type of syncope and affects about 25% of the population. The role of genetic factors in VVS has long been debated. In this review we will discuss the current evidence that strongly suggests a major genetic component.
CLINICAL GENETIC STUDIES
Family aggregation studies have consistently shown that individuals with VVS more frequently have affected family members with VVS than unaffected controls. Clear evidence for the relevance of genetic factors was provided by a twin study that showed significantly higher concordance rates in monozygous compared to dizygous twins for frequent syncope and syncope associated with typical vasovagal triggers. Analysis of the family history of the concordant monozygous twins revealed that complex inheritance is operative in the majority but rarer families with autosomal dominant inheritance also exist. Several autosomal dominant families have been described in the literature with the largest including 30 affected individuals.
MOLECULAR GENETIC STUDIES
Candidate gene association studies have so far been disappointing as they have revealed either negative or unconfirmed results. However, in an autosomal dominant family the first locus for VVS was identified on chromosome 15q26. The underlying gene has not been identified yet.
CONCLUSION
Genetic factors play a role in VVS. Most cases follow complex inheritance; autosomal dominant inheritance occurs less frequently. Identification of the underlying genes will improve our understanding of pathophysiology and may lead to new therapeutic strategies.
Topics: Humans; Syncope, Vasovagal
PubMed: 24794249
DOI: 10.1016/j.autneu.2014.03.008 -
Clinical Autonomic Research : Official... Feb 2022Sleep syncope is defined as a form of vasovagal syncope which interrupts sleep. Long term follow-up has not been reported.
PURPOSE
Sleep syncope is defined as a form of vasovagal syncope which interrupts sleep. Long term follow-up has not been reported.
METHODS
Between 1999 and 2013 we diagnosed vasovagal syncope in 1105 patients of whom 69 also had sleep syncope. We compared these 69 patients in the sleep syncope group to 118 patients with classical vasovagal syncope consecutively investigated between 1999 and 2003. We compared baseline demography, syncope history, tilt test results and follow-up findings.
RESULTS
At baseline, age and gender distribution (mean ± standard deviation) of the classical VVS and sleep synocope groups were similar: 46 ± 21 vs. 47 ± 15 years (p = 0.53), and 55% versus 66% female (p = 0.28), respectively. Abdominal discomfort and vagotonia were more frequent in sleep syncope patients: 80% versus 8% and 33% versus 2% (p < 0.001). Childhood syncope and blood-needle phobia were also more frequent in sleep syncope patients: 58% versus 15% and 69% versus 19% (p < 0.001). Positive tilt test results were similar for the two groups (93% [classical VVS] vs. 91%; p = 0.56). Blood pressure, heart rate and stroke volume changed in a similar manner from baseline to syncope (p = 0.32, 0.34 and 0.18, respectively). Mean duration of follow-up for the classical VVS and sleep syncope groups, as recorded in the electronic records, were 17 (3-21) and 15 (7-27) years, respectively. Rates of mortality and of permanent pacemaker insertion were similar in the two groups: 16.2% (classical VVS) versus 7.6% (p = 0.09) and 3% (classical VVS) versus 3% (p = 0.9). Incidence of sleep episodes decreased from 1.9 ± 3 to 0.1 ± 0.3 episodes per year (p < 0.001).
CONCLUSION
Sleep syncope is a subtype of vasovagal syncope with characteristic symptoms. Despite the severity of the sleep episodes, the prognosis is very good. Very few patients require permanent pacing, and nearly all respond to education and reassurance.
Topics: Child; Female; Humans; Male; Prospective Studies; Sleep; Syncope; Syncope, Vasovagal; Tilt-Table Test
PubMed: 34997395
DOI: 10.1007/s10286-021-00842-1 -
Herzschrittmachertherapie &... Sep 2021This review discusses important aspects of pathophysiology, diagnosis and therapy of reflex syncope. The autonomic nervous system plays a crucial role in the origin of... (Review)
Review
This review discusses important aspects of pathophysiology, diagnosis and therapy of reflex syncope. The autonomic nervous system plays a crucial role in the origin of this frequently observed form of syncope. In most cases, reflex syncopes occur under specific circumstances. Thus, a detailed history is essential. Besides a physical exam und a normal 12-lead ECG, dedicated tests like tilt-table-testing, carotid massage and the implantation of a loop recorder often assist in making the correct diagnosis. The basis of therapy for all patients is reassurance about the benign course of the disease as well as education about adequate measures. Pharmacotherapy is reserved to a minority of patients. In older patients with repeat or severe syncopes and documented asystoles, pacemaker therapy is a valuable option.
Topics: Aged; Autonomic Nervous System; Humans; Pacemaker, Artificial; Reflex; Syncope; Syncope, Vasovagal
PubMed: 34189616
DOI: 10.1007/s00399-021-00775-2 -
World Journal of Pediatrics : WJP Jan 2022
Topics: Child; Humans; Syncope, Vasovagal; Tilt-Table Test
PubMed: 34982400
DOI: 10.1007/s12519-021-00495-0 -
Trends in Cardiovascular Medicine Nov 2018The benefit of conventional pacing in vasovagal syncope remains controversial and is currently recommended for patients with recurrent syncope and documented asystole.... (Review)
Review
The benefit of conventional pacing in vasovagal syncope remains controversial and is currently recommended for patients with recurrent syncope and documented asystole. In the last two decades, a growing body of evidence has emerged supporting the use of a new sensing technique called closed loop stimulation or CLS, to treat refractory vasovagal syncope. CLS uses a sensing algorithm that can detect variation in cardiac contractility and respond to drop in blood pressure by increasing the heart rate. Multiple observational and randomized studies have assessed its efficacy and showed its superiority to conventional pacing in reducing the burden of syncopal attacks in patients with cardio-inhibitory vasovagal syncope.
Topics: Algorithms; Cardiac Pacing, Artificial; Clinical Decision-Making; Equipment Design; Hemodynamics; Humans; Pacemaker, Artificial; Remote Sensing Technology; Signal Processing, Computer-Assisted; Syncope, Vasovagal; Treatment Outcome
PubMed: 29843961
DOI: 10.1016/j.tcm.2018.05.003 -
Clinical Autonomic Research : Official... Aug 2017
Topics: Cardiac Pacing, Artificial; Heart Arrest; Humans; Pacemaker, Artificial; Syncope, Vasovagal
PubMed: 28710604
DOI: 10.1007/s10286-017-0447-1 -
Autonomic Neuroscience : Basic &... Sep 2014Vasovagal syncope (VVS) is a common disorder of the autonomic nervous system. While recurrent syncope can cause very impaired quality of life, the spells are not... (Review)
Review
Vasovagal syncope (VVS) is a common disorder of the autonomic nervous system. While recurrent syncope can cause very impaired quality of life, the spells are not generally life-threatening. Both non-pharmacological and pharmacological approaches can be used to treat patients. Conservative management with education, exercise and physical maneuvers, and aggressive volume repletion is adequate for controlling symptoms in most patients. Unfortunately, a minority of patients will continue to have recurrent syncope despite conservative therapy, and they may require medications. These could include vasopressor agents, beta-blockers, or neurohormonal agents. Some patients may require more aggressive device based therapy with pacemakers or radiofrequency ablation, which are emerging therapies for VVS. This paper will review non-procedure based treatments for VVS.
Topics: Animals; Humans; Syncope, Vasovagal
PubMed: 24996861
DOI: 10.1016/j.autneu.2014.06.004