Assessment of Efficacy of Oral Rehydration Salts in Children With Neurally Mediated Syncope of Different Hemodynamic Patterns

The Role of the Autonomic Nervous System in Vasovagal Syncope

The mechanism of vasovagal syncope (VVS) is multifaceted and involves a delicate balance within the autonomic nervous system (ANS). This review delves into the complex interplay between the ANS and VVS, elucidating the pivotal role that autonomic imbalance plays in the pathophysiology of this condition. Through a comprehensive exploration of the sympathetic and parasympathetic branches of the ANS, this review provides insights into the mechanisms that underlie VVS. In addition, this article discusses established and emerging research on the management of VVS.

Therapeutic options for neurocardiogenic syncope: a meta-analysis of randomised trials with and without blinding

BACKGROUND

Neurocardiogenic syncope is a common condition with significant associated psychological and physical morbidity. The effectiveness of therapeutic options for neurocardiogenic syncope beyond placebo remains uncertain.

METHODS

The primary endpoint was the risk ratio (RR) of spontaneously recurring syncope following any therapeutic intervention. We also examined the effect of blinding on treatment efficacy. We identified all randomised trials which evaluated the effect of any pharmacological, device-based or supportive intervention on patients with a history of syncope. A systematic search was conducted on Medline, Embase, PubMed databases and Cochrane Central Register for Controlled Trials from 1950 to 25 April 2023. Event rates, their RRs and 95% CIs were calculated, and a random-effects meta-analysis was conducted for each intervention. Data analysis was performed in R using RStudio.

RESULTS

We identified 47 eligible trials randomising 3518 patients. Blinded trials assessing syncope recurrence were neutral for beta blockers, fludrocortisone and conventional dual-chamber pacing but were favourable for selective serotonin reuptake inhibitors (SSRIs) (RR 0.40, 95% CI 0.26 to 0.63, p<0.001), midodrine (RR 0.70, 95% CI 0.53 to 0.94, p=0.016) and closed-loop stimulation (CLS) pacing (RR 0.15, 95% CI 0.07 to 0.35, p<0.001). Unblinded trials reported significant benefits for all therapy categories other than beta blockers and consistently showed larger benefits than blinded trials.

CONCLUSIONS

Under blinded conditions, SSRIs, midodrine and CLS pacing significantly reduced syncope recurrence. Future trials for syncope should be blinded to avoid overestimating treatment effects.

PROSPERO REGISTRATION NUMBER

CRD42022330148.

Relationship between hemodynamic type and syncopal symptoms in pediatric vasovagal syncope

Vasovagal syncope (VVS) is a clinically common neurally mediated syncope. The relationship between different hemodynamic types of VVS and clinical syncopal symptoms has not been reported. The purpose of this research is to explore relationship between hemodynamic types and syncopal symptoms in pediatric VVS. Two thousand five hundred thirteen patients diagnosed with VVS at the age of 3-18 years, average age was 11.76 ± 2.83 years, including 1124 males and 1389 females, due to unexplained syncope and pre-syncope from single-center of January 2001 to December 2021 were retrospectively analyzed. Subjects were divided into two groups according to the presence or absence of syncopal symptoms: syncope group (1262 cases) and pre-syncope group (1251 cases). (1) Baseline characteristics: age, height, weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP) increased in the syncope group compared with the pre-syncope group; the composition ratio of females was more than that of males in the syncope group; and the composition ratio of VVS-cardioinhibited (VVS-CI) and VVS-mixed (VVS-M) was more in the syncope group than that of the pre-syncope group (all P < 0.05). (2) Univariate analysis: age, height, weight, SBP, DBP, female, VVS-CI, and VVS-M were potential risk factors for the presence of syncopal symptoms (all P < 0.05). (3) Multivariate analysis: VVS-CI and VVS-M were independent risk factors for the presence of syncopal symptoms, with an increased probability of 203% and 175%, respectively, compared to VVS-vasoinhibited (VVS-VI) (all P < 0.01).

CONCLUSION

The hemodynamic type of pediatric VVS is closely related to the syncopal symptoms.

WHAT IS KNOWN

• There are varying probabilities of syncopal episodes in different hemodynamic types of VVS, and there is a lack of research to assess the comparative risk of syncope in children with different hemodynamic types of VVS.

WHAT IS NEW

• The probability in presence of syncopal symptoms varies greatly between different hemodynamic types of VVS. • VVS-CI and VVS-M had a 203% and 175% increased risk in presence of syncopal symptoms compared with VVS-VI, respectively.

Spectrum of underlying diseases in syncope and treatment of neurally-mediated syncope in children and adolescents over the past 30 years: A single center study

Background

Syncope is the primary cause of transient loss of consciousness, which causes severe physical and mental burdens to children and adolescents.

Objective

The study was designed to analyze the spectrum of underlying diseases of syncope and treatment options for neurally-mediated syncope (NMS) in Chinese children and adolescents.

Methods

Medical records including history, physical examination, blood biochemistry, standing test, head-up tilt (HUTT), sitting-up test, electroencephalogram (EEG), electrocardiogram (ECG), and echocardiography were retrospectively studied in children and adolescents admitted to the National Pediatric Syncope Center, Department of Pediatrics, Peking University First Hospital between 1992 and 2021. All the data were collected from the Beijing Kaihua Medical Management System (Kaihua, Beijing, China). Children who met the syncope diagnostic criteria were enrolled in the study. The spectrum of the underlying diseases of syncope in children and adolescents and the treatment options of NMS were analyzed.

Results

A total of 1,947 children and adolescents with syncope were admitted, including 869 males (44.63%) and 1,078 females (55.37%) aged 1-18 years, with an average age of 11.1 ± 3.1 years. The number of children and adolescents with syncope displayed a gradually increasing trend between 1992 and 2021 except after 2020. NMS proportion increased, and the proportion of unexplained syncope decreased (χ2 = 128.839, P < 0.01). The treatment options of NMS mainly included autonomic nervous function exercise (549, 34.46%), oral rehydration salt (ORS; 445, 27.94%), metoprolol (219, 13.75%), midodrine (120, 7.53%), ORS plus metoprolol (139, 8.73%), ORS plus midodrine (120, 7.53%), and pacemakers (1, 0.06%). Patients with vasovagal syncope (VVS) coexisting with postural orthostatic tachycardia syndrome (POTS) were more likely to take pharmacological treatments than those with VVS or POTS only (χ2 = 41.696, P < 0.01).

Conclusion

The number of children with syncope displayed an increasing trend before 2020, and the proportion of unexplained syncope decreased. Autonomic nervous function exercise was the most common treatment for children and adolescents with NMS. Children with VVS coexisting with POTS were more likely to receive pharmacological treatments than those with either.

Understanding the use of oral rehydration therapy: A narrative review from clinical practice to main recommendations

Background and Aims

Fluid loss due to diarrhea remains a significant cause of mortality among children under the age of 5.

Methods

Oral rehydration therapy (ORT) is a first-line therapeutic measure to compensate the volume loss due to diarrhea and vomiting among gastroenteritis patients. Despite adequate knowledge, the practice of ORT is limited, particularly in developing countries.

Results

Several recommendations are provided regarding the use of ORT to treat hypovolemia, however, the information regarding its adequate usage is restricted within the healthcare centers and professionals.

Conclusion

This review highlights the importance of providing recommendations regarding the use of ORT. We also discuss the barriers and alternatives that might limit its use.

Clinical Efficacy of Empirical Therapy in Children with Vasovagal Syncope

(1) Background: This case-control study was designed to assess the efficacy of empiric treatment for vasovagal syncope in children; (2) Methods: We retrospectively enrolled 181 children with vasovagal syncope from the Department of Pediatrics of Peking University First Hospital. The participants were categorized into four groups, based on the empiric treatment received: conventional treatment, including health education and orthostatic training; conventional treatment plus oral rehydration salts; conventional treatment plus metoprolol; conventional treatment plus midodrine hydrochloride. Patients were followed up to evaluate the syncopal or presyncopal recurrence. Kaplan-Meier curves were drawn to explore the syncopal or presyncopal recurrence in children, and the differences were compared among the groups using a log-rank test; (3) Results: Among the 181 children with vasovagal syncope, 11 were lost to follow-up. The median time of follow-up was 20 (8, 42) months. The Kaplan-Meier survival curve showed no significant difference in syncopal or presyncopal recurrence in children treated with different empiric options according to a log-rank test (χ2 = 1.328, p = 0.723); (4) Conclusions: The efficacy of unselected empiric therapy of vasovagal syncope in children was limited, and the individualized therapies merit further studies.

Risk Factors and Prognostic Follow-Up of Vasovagal Syncope Children With Seizure-Like Activities During Head-Up Tilt Test Induced-Syncope

Objectives

To analyze the risk factors associated with seizure-like activities during head up tilt test (HUTT)-induced syncope in children with vasovagal syncope (VVS) and assess the prognosis of these patients.

Methods

This is a retrospective study. VVS children with or without seizure-like activities during HUTT-induced syncope were included in convulsive or non-convulsive group. The clinical characteristics, hemodynamic parameters during HUTT-induced syncope and follow-up data were reviewed from the HUTT case report form and analyzed.

Results

68 cases (25 males, mean age 11.86 ± 3.35 years) were enrolled in convulsive group and 65 cases in non-convulsive group (24 males, mean age 11.64 ± 2.11 years). There were statistical differences in history duration, response type, and asystole between the two groups (all P < 0.05). Fully adjusted logistic regression showed that the risk of seizure-like activities was increased by 37.18 folds for patients with asystole compared with those without asystole (P = 0.005), by 308.25 and 6.08 folds for patients with cardioinhibitory type or mixed type compared with vasoinhibitory type (P < 0.01). No significant difference was exhibited in negative HUTT conversion rate and the proportion of re-syncope patients between the two groups at follow-up (both P > 0.05). None of these convulsive patients underwent pacemaker implantation during follow-up.

Conclusions

Asystole and response type were independent risk factors associated with seizure-like activities. Patients with asystole and mixed or cardioinhibitory responses to HUTT should be closely concerned. However, VVS children with seizure-like activities did not have a poor prognosis at follow-up.

Salt supplementation in the management of orthostatic intolerance: Vasovagal syncope and postural orthostatic tachycardia syndrome

Salt supplementation is a common non-pharmacological approach to the management of recurrent orthostatic syncope or presyncope, particularly for patients with vasovagal syncope (VVS) or postural orthostatic tachycardia syndrome (POTS), although there is limited consensus on the optimal dosage, formulation and duration of treatment. Accordingly, we reviewed the evidence for the use of salt supplementation to reduce susceptibility to syncope or presyncope in patients with VVS and POTS. We found that short-term (~3 months) salt supplementation improves susceptibility to VVS and associated symptoms, with little effect on supine blood pressure. In patients with VVS, salt supplementation is associated with increases in plasma volume, and an increase in the time taken to provoke a syncopal event during orthostatic tolerance testing, with smaller orthostatic heart rate increases, enhanced peripheral vascular responses to orthostatic stress, and improved cerebral autoregulation. Responses were most pronounced in those with a baseline sodium excretion <170 mmol/day. Salt supplementation also improved symptoms, plasma volume, and orthostatic responses in patients with POTS. Salt supplementation should be considered for individuals with recurrent and troublesome episodes of VVS or POTS without cardiovascular comorbidities, particularly if their typical urinary sodium excretion is low, and their supine blood pressure is not elevated. The efficacy of the response, in terms of the improvement in subjective and objective markers of orthostatic intolerance, and any potential deleterious effect on supine blood pressure, should be routinely monitored in individuals on high salt regimes.

Management strategies for vasovagal syncope

Vasovagal syncope (VVS) (or neurocardiogenic syncope) is a common clinical condition that is challenging to both physicians and patients alike. Severe episodes of recurrent syncope can result in physical injury as well as psychological distress. This article provides a brief overview of current management strategies and a detailed overview of therapeutic modalities such as closed loop stimulation (CLS) and cardioneuroablation (CNA).

Efficacy of Increased Salt and Water Intake on Pediatric Vasovagal Syncope: A Meta-Analysis Based on Global Published Data

Objective: This study was designed to assess the efficacy of increased salt and water intake in the treatment of pediatric vasovagal syncope (VVS) based on a meta-analysis of global data. Methods: Following the established inclusion criteria, seven databases, Cochrane Library, EMBASE, PubMed, Web of Science, VIP, Wanfang, and China National Knowledge Infrastructure (CNKI), were searched using specific terms. The Cochrane Bias risk assessment tool was used as a quality assessment tool of the included studies, and publication bias was assessed by funnel plots. Review Manager 5.4 software was used to analyze the efficacy of the included studies, taking the negative changing rate of the head-up tilt test (HUTT) and recurrence rate of syncope or presyncope as therapeutic efficacy evaluations. Results: In total, 5 randomized controlled trials (RCTs) were finally obtained, using the negative changing rate of the HUTT as an efficacy evaluation, while in 4 of the studies, the recurrence rate of syncope or presyncope was also evaluated. A total of 233 children with VVS were included in the salt and water intervention group. The cases in the control group were treated with non-medicinal conventional therapy. The results revealed that the negative changing rate of the HUTT in the intervention group (144/233, 61.8%) was higher than that in the control group (48/179, 26.8%), and the difference was significant (P < 0.00001). The recurrence rate of syncope or presyncope in the intervention group (85/195, 43.6%) was lower than that in the control group (86/144, 59.7%), and the difference was significant (P = 0.002). Conclusion: The current findings suggest that increased salt and water intake may increase the negative changing rates of the HUTT and reduce syncope or presyncope recurrence rates in pediatric patients with VVS.

The predictive value of urine specific gravity in the diagnosis of vasovagal syncope in children and adolescents

BACKGROUND

Vasovagal syncope (VVS) is a kind of common neurally mediated syncope in children and adolescents. Decreased blood volume is one of the pathogenesis of VVS. The diagnosis of VVS is mainly based on head-up tilt test (HUTT), but some complications may easily occur when HUTT induces syncope. To find a simple and safe VVS diagnosis method can improve the VVS diagnosis efficiency.

AIMS OF THE STUDY

This was a prospective study. The study will explore the predictive value of urine specific gravity (USG) in the diagnosis of VVS in children and adolescents.

PATIENTS AND METHODS

Ninety-seven cases (43 males and 54 females, aged 4 to 16 years old, with an average age of 10.91 ± 2.18 years old) hospitalized due to unexplained premonitory syncope or syncope and diagnosed with VVS through HUTT from September 2014 to September 2018 were selected as VVS group. During the same period, 91 cases of children and adolescents, including 45 males and 46 females, aged from 5 to 15 years old, who underwent a healthy examination were matched as a control (control group). USG was measured in both groups.

RESULTS

The USG of VVS group was significantly lower than that of the control group (P < 0.01), and USG of females was lower than that of males in VVS group (P = 0.045). The sensitivity and specificity of USG in predicting VVS were evaluated by ROC curve. The area under the ROC curve was 0.751, standard error was 0.035, and 95% CI (0.683, 0.819) suggested that USG was of moderate predictive value in the diagnosis of VVS. As cut-off value of USG was 1.0185, the sensitivity and specificity and diagnostic coincidence rate of VVS were 74.39, 66.04 and 69.68%, respectively.

CONCLUSION

There are less USG in children and adolescents with VVS, especially lower USG in females. Therefore, USG has predictive value in the diagnosis of VVS in children and adolescents.