Risk factors associated with malignant vasovagal syncope in children / 中华儿科杂志

Objective: To analyze the clinical characteristics and risk factors of malignant vasovagal syncope (VVS) in children. Methods: This was a case-control study. The data of 368 VVS patients who were treated in the Department of Cardiology, Children's Hospital, Capital Institute of Pediatrics from June 2017 to December 2021 was collected and analyzed. They were divided into malignant VVS group and non-malignant VVS group according to the presence of sinus arrest, and then their demographic characteristics were compared. The children with malignant VVS and complete clinical information were recruited into the case group and were matched by age and sex (1∶4 ratio) with non-malignant VVS patients during the same period.Their clinical characteristics and lab tests were compared. Independent sample t test, Mann Whitney U or χ2 test was used for comparison between groups.Logistic regression was used to analyze the risk factors for malignant VVS in children. Results: Eleven malignant VVS and 342 non-malignant VVS met the inclusion and exclusion critera. Eleven malignant VVS and 44 non-malignant children were recruited in the case-control study. Ten patients of the 11 malignant VVS had a cardiac arrest occurring at 35 (28, 35) minutes of the head-up tilt test, and the duration of sinus arrest was (9±5) s. One patient had syncope occurring while waiting for drawing blood, and the duration of sinus arrest was 3.4 s. The children with malignant vasovagal syncope were younger than non-malignant VVS patients (9 (7, 10) vs. 12 (10, 14) years old, P<0.05), and had higher mean corpuscular hemoglobin concentration (MCHC) and standard deviation of the mean cardiac cycle over 5-minute period within 24 hours ((347±9) vs. (340±8) g/L, (124±9) vs. (113±28) ms, both P<0.05). Logistic regression analysis showed that MCHC was an independent risk factor for malignant VVS in pediatric patients (OR=1.13, 95%CI 1.02-1.26, P=0.024). Conclusions: The onset age of malignant VVS was younger, with no other special clinical manifestations. MCHC was an independent risk factor for malignant VVS.

Utilidad de la midodrina para controlar el síncope vasovagal: ¿la recomienda la evidencia? / Usefulness of Midodrine for the Control of Recurrent Vasovagal Syncope: Does the Evidence Recommend it? / Utilidade da midodrina no controle da síncope vasovagal: as evidencias a recomendam?

Introducción:El síncope vasovagal es la principal causa de pérdida transitoria de la conciencia, y es un motivo de consulta cada vez más frecuente en pediatría y medicina del adulto. La midodrina es un agonista de los recepto-res alfa, de acción periférica, empleada principalmente en el manejo de la hipotensión ortostática; sin embargo, también se ha evaluado en el síncope vasovagal, con resultados prometedores.Objetivo:Analizar la evidencia más reciente sobre la utilidad de la midodrina para el control y la prevención del síncope vasovagal.Materiales y métodos: Se realizó una búsqueda bibliográfica utilizando términos de búsqueda como Vasovagal Syncope y Midodrine, así como sinónimos, que se combinaron con operadores booleanos, en cinco bases de datos, hasta octubre del 2022. Se incluyeron estudios originales, revisiones sistemáticas y metanálisis, publicados tanto en inglés como en español.Resultados:Ensayos controlados aleatorizados y revisiones sistemáticas y metanálisis difieren ligeramente entre resultados, pero estos demuestran un efecto global protector. La evidencia más reciente y completa indica que utilizar este agente reduce significativamente la positividad al realizar la prueba de la mesa inclinada y que previene la aparición de episodios sincopales.Conclusiones:Aunque la evidencia actual sobre la eficacia de la midodrina respecto a la prevención y control del síncope vasovagal es limitada, se observa un efecto protector significativo, porque disminuye el riesgo de sufrir un episodio sincopal, aproximadamente hasta en un 50 %.Palabras clave: midodrina; síncope vasovagal; síncope; adrenérgicos; medicina basada en la evidencia

Introduction: Vasovagal syncope is the main cause of transient loss of consciousness, being an in-creasingly frequent reason for consultation in pediatrics and adult medicine. Midodrine, a periphe-rally acting alpha-receptor agonist, is mainly used in the management of orthostatic hypotension. However, it has also been evaluated in vasovagal syncope, with promising results. Objective: To analyze the most recent evidence on the usefulness of midodrine for the control and prevention of vasovagal syncope. Materials and Methods: A literature search was performed using search terms such as "Vasovagal Syncope" and "Midodrine," as well as synonyms, which were combined with Boolean operators, in 5 databases until October 2022. Original studies, systematic reviews and meta-analyses, published in both English and Spanish, were included. Results: Randomized controlled trials and systematic reviews and meta-analyses differ slightly between results, but these demonstrate an overall protective effect. The most recent and complete evidence shows that using this agent significantly reduces the probability of positivity when performing the tilt table test and prevents the occurrence of syncopal episodes. Conclusions: Although current evidence on the efficacy of midodrine with respect to the prevention and control of vasovagal syncope is limited, a significant protective effect is observed, reducing the risk of suffering syncopal episode by approximately up to 50%

Introdução: a síncope vasovagal é a principal causa de perda transitória de consciência e é um motivo cada vez mais comum de consulta em pediatria e medicina de adultos. A midodrina é um agonista do receptor alfa de ação periférica usado principalmente no tratamento da hipotensão ortostática; no entanto, ela também foi avaliada na síncope vasovagal, com resultados promissores. Objetivo: Revisar as evidências mais recentes sobre a utilidade da midodrina para o controle e a pre-venção da síncope vasovagal. Materiais e métodos: Foi realizada uma pesquisa na literatura usando termos de pesquisa como Va-sovagal, Syncope e Medodrine, bem como sinônimos, que foram combinados com operadores boo-leanos, em cinco bancos de dados, até outubro de 2022. Foram incluídos estudos originais, revisões sistemáticas e metanálises, publicados em inglês e espanhol. Resultados: Os ensaios clínicos randomizados, as revisões sistemáticas e as metanálises diferem ligei-ramente entre os resultados, mas demonstram um efeito protetor geral. As evidências mais recentes e abrangentes indicam que o uso desse agente reduz significativamente a positividade no teste de inclinação da mesa e evita a ocorrência de episódios de síncope. Conclusões: Embora as evidências atuais sobre a eficácia da midodrina em relação à prevenção e ao controle da síncope vasovagal sejam limitadas, observa-se um efeito protetor significativo, pois ela diminui o risco de sofrer um episódio sincopal em aproximadamente 50%

Cardioneuroablación como tratamiento del síncope reflejo: reporte de un caso

Resumen: El síncope mediado neuralmente es un trastorno causado por un reflejo autónomo anormalmente amplificado que involucra componentes tanto simpáticos como parasimpáticos. Es la causa más frecuente de síncope en personas jóvenes y su tratamiento sigue siendo un desafío, ya que no se ha demostrado que alguna terapia farmacológica prevenga por completo su recurrencia. En los últimos años ha surgido una técnica denominada cardioneuroablación, que consiste en la ablación por radiofrecuencia de los plexos ganglionares (PG) parasimpáticos, con buenos resultados a corto y largo plazo en la prevención de síncope recurrente, según los diferentes grupos de investigación. Presentamos el primer caso en Chile de un hombre joven con síncopes mediados neuralmente recurrentes que fue tratado con esta técnica en el Hospital Regional de Concepción.

Abstract: Cardioneuroablation is a novel method that can be used to treat reflex syncope. Although the experience with this technique is relatively limited it provides a more physiological way to treat this condition. The first case in Chile is herein reported along with a discussion of the subject.

Coefficient of variation of heart rate and blood pressure in rapid identification of children with suspected orthostatic intolerance / 中华儿科杂志

Objective: To investigate the clinical value of coefficient of variation of heart rate and blood pressure in rapid identification of children with suspected orthostatic intolerance(OI). Methods: This was a retrospective study. The medical records of 379 children with OI were collected, who were admitted to the Department of Pediatrics of Qilu Hospital of Shandong University from January 2015 to January 2020. Another 20 out-patient children without syncope or syncope aura were selected as control. According to the results of standing test and head-up tilt test (HUTT), all the patients with OI were divided into the following 4 groups: vasovagal syncope (VVS) group, postural tachycardia syndrome (POTS) group, POTS combined with VVS (POTS+VVS) group and HUTT negative group. Then, coefficient of variation of systolic pressure (SBPCV), coefficient of variation of diastolic pressure (DBPCV) and coefficient of variation of heart rate (HRCV) in standing test and HUTT were calculated. Kruskal-Wallis test was used for comparison among the five groups, and Dunnett's T3 method for comparison between two groups. Paired t test was used to compare the coefficient of variation between supine and erect position and tilt position in each group. The predictive values of HRCV,SBPCV and DBPCV for negative HUTT were evaluated by receiver operating characteristic (ROC) curve. Results: Among the 379 children, there were 79 in HUTT negative group, 208 in VVS group, 52 in POTS group, and 40 in POTS+VVS group. The SBPCV of supine-erect position of the control group, HUTT negative group, VVS group, POTS group, POTS+VVS group were (3.8±1.0)%, (5.3±2.2)%, (6.6±3.4)%, (5.9±3.6)%, (6.9±2.8)%, respectively. Similarly, the SBPCV of supine, erect and head-up tilt position were (4.5±0.8)%, (6.0±1.9)%, (7.1±2.6)%, (6.0±2.1)%, (7.3±2.5)%; the DBPCV of supine-erect position were (7.3±1.2)%, (9.1±3.7)%, (9.1±4.9)%, (9.1±4.8)%, (11.6±4.6)%; the DBPCV of supine, erect and tilt position were (7.4±1.1)%, (9.4±2.9)%, (10.1±3.8)%, (9.2±3.3)%, (11.0±4.7)%; the HRCV of supine-erect position were (7.6±2.6)%, (12.9±3.7)%, (16.2±4.3)%, (21.2±5.9)%, (24.9±5.3)%; and the HRCV of supine, erect and tilt position were (8.1±1.6)%, (10.1±2.7)%, (14.1±4.3)%, (15.6±3.7)%, (18.9±4.0)%, respectively. All the indexes showed significant differences among the five groups (χ2=21.91, 25.47, 19.82, 14.65, 104.52, 92.51, all P<0.05). ROC curve analysis showed that when the SBPCV and HRCV of supine-erect position reached 4.4% and 10.5%, the area under the curve of ROC were 0.713 and 0.877, the sensitivity of predicting negative HUTT were 58.2% and 78.5%, and the specificity were 80.0% and 95.0%, respectively. Conclusions: Coefficient of variation of heart rate and blood pressure may serve as potential diagnostic indexes in evaluating autonomic function of OI patients. SBPCV ≥ 4.4% or HRCV ≥ 10.5% of supine-erect position could be an indication of HUTT.

Evaluación de la frecuencia cardiaca durante la bipedestación activa inicial en pacientes que padecen síncope vasovagal / Evaluation of the heart rate during initial active standing in patients with vasovagal syncope

Introducción: El síncope vasovagal es la causa más frecuente de pérdida breve de la conciencia, en su etiopatogenia se reporta una disfunción autonómica que puede ponerse de manifiesto en la bipedestación activa inmediata. Objetivo: Comparar la dinámica de los cambios de la frecuencia cardíaca durante la bipedestación activa inmediata, de pacientes que padecen síncope vasovagal y sujetos controles. Métodos: Se evaluaron 132 sujetos supuestamente sanos (grupo A) entre 18 y 25 años y 156 pacientes con síncopes vasovagales; fueron divididos por su respuesta ante la bipedestación prolongada, negativa 111 (grupo B) y positiva 45 (grupo C). Se registró la actividad electrocardiográfica en decúbito supino y al inicio de la bipedestación activa, se obtuvo las secuencias de intervalos RR. Se comparó la frecuencia cardíaca en los 3 grupos, con 22 indicadores (posicionales, temporales, ordinales y relacionales, promedio y de la velocidad de los cambios). Resultados: No hubo diferencias en los indicadores promedio, sin embargo, algunos que evalúan la velocidad del cambio inicial, fueron significativamente menores en el grupo A comparado con B y C (p < 0,05), mientras que los que evalúan la velocidad de recuperación, fueron significativamente menores en el grupo C comparado con A y B. Conclusión: La dinámica de los cambios de frecuencia, permitió encontrar indicadores que pueden considerarse posibles predictores de una respuesta cardiovascular inadecuada en pacientes con síncope vasovagal(AU)

Introduction: Vasovagal syncope is the most frequent cause of brief loss of consciousness, in its etiopathogenesis an autonomic dysfunction is reported that can be manifested in immediate active standing. Objective: To compare the dynamics of heart rate changes during immediate active standing of patients suffering from vasovagal syncope with control subjects. Methods: 132 supposedly healthy subjects (group A) between 18 and 25 years old and 156 patients with vasovagal syncope were evaluated, which were divided by their response to prolonged standing, negative 111 (group B) and positive 45 (group C). Electrocardiographic activity was recorded in the supine position and at the beginning of active standing, the sequences of RR intervals were obtained. The heart rate was compared in the 3 groups, using 22 indicators (positional, temporal, ordinal and relational, average and of the speed of changes). Results: Differences were not found in the average indicators in the analyzed period, however, some that evaluate the speed of the initial change were significantly lower in group A compared to B and C (p < 0.05), while others that evaluate the speed recovery rates were significantly lower in group C compared to A and B. This allows to characterize, compare and differentiate the groups studied during the complex and rapid interactions that occur in the change of position. Conclusion: The dynamic of frequency changes, allowed to find indicators, which can be considered as possible predictors of an inadequate cardiovascular response in patients with vasovagal syncope(AU)

Urgencias médicas durante la experiencia profesional de estomatólogos en La Habana / Medical emergencies in the professional practice of Havana dentists

Introducción: Las urgencias médicas durante la atención estomatológica son eventos que pueden poner en peligro la salud de los pacientes. Objetivo: Caracterizar las urgencias médicas que se les han presentado a los estomatólogos durante su práctica profesional. Métodos: Se realizó un estudio descriptivo y transversal, de enero a marzo de 2019. El universo estuvo constituido por los estomatólogos de 12 de las 20 clínicas estomatológicas de subordinación docente a la Facultad de Estomatología de La Habana "Raúl González Sánchez". Variables utilizadas fueron: presencia de urgencias, tipo de especialidades, frecuencia de las urgencias médicas, tipo de urgencia médica, procederes estomatológicos y cantidad de urgencias. Resultados: El 61,2 por ciento de los encuestados refirió que eran eventos poco frecuentes, el 50,8 por ciento presentó dos urgencias médicas. Las urgencias más frecuentes fueron las lipotimias (29,9 por ciento) y los síncopes vaso vágales (25,2 por ciento). Conclusiones: Las urgencias médicas son eventos que pueden producirse durante la atención estomatológica. El presente estudio aborda un área del conocimiento poco estudiada en Estomatología en Cuba. Los profesionales, durante los procederes estomatológicos, juegan un papel protagónico en la prevención de las urgencias médicas y en su tratamiento inicial. Los datos epidemiológicos y clínicos de estos eventos, aportados por esta investigación, pueden servir de referencia a otros estudios(AU)

Introduction: Medical emergencies occurring during dental care may pose a risk to the health of patients. Objective: Characterize medical emergencies experienced by dentists in their professional practice. Methods: A descriptive cross-sectional study was conducted from January to March 2019. The study universe was the dentists of 12 of the 20 university dental clinics attached to the Dental School of Havana. The variables analyzed were occurrence of emergencies, specialty, frequency of medical emergencies, type of medical emergency, dental procedures and number of emergencies. Results: 61.2 percent of the respondents stated that medical emergencies were not frequent, and 50.8 percent reported two medical emergencies. The most common emergencies were loss of consciousness (29.9 percent) and vasovagal syncope (25.2 percent). Conclusions: Medical emergencies may occur during dental care. The study addresses an area of dental practice not much dealt with in Cuba. During the performance of dental procedures, professionals play a leading role in the prevention of medical emergencies and their initial treatment. The epidemiological and clinical data about these events contributed by this research may serve as reference for other studies(AU)

Detección de síncope vasovagal con adaptación de la Escala de Calgary en estudiantes universitarios colombianos / Using a Calgary Scale adaptation to detect vasovagal syncope in Colombian university students

Resumen Introducción: El síncope vasovagal tiene una incidencia entre 10% y 19% en la población general, el primer episodio suele aparecer en la juventud. Objetivo: Estimar la prevalencia de síncope vasovagal en una población universitaria del sur de Colombia, utilizando una adaptación de la Escala de Calgary como cuestionario diagnóstico. Materiales y métodos: Después de la firma voluntaria del consentimiento informado, los estudiantes fueron entrevistados y se les aplicó la Escala de Calgary. Posteriormente, se realizó un cuestionario de seguimiento a los participantes positivos. Resultados: Participaron 280 estudiantes, el 17% obtuvo un puntaje positivo para síncope vasovagal. La edad media fue 21,45±5,18; con mayor positividad para el género femenino. En el seguimiento, el 10% de los positivos, consultó a urgencias por pérdida de conciencia, 4% fue ingresado a hospitalización y 10% presentó lesiones secundarias. Conclusiones: Un número representativo de participantes fue positivo en la Escala de Calgary, ninguno de ellos había recibido diagnóstico de síncope neuralmente mediado, pese a haber consultado a urgencias y/o presentar lesiones secundarias por pérdida de conciencia. Incluir la Escala de Calgary en la evaluación inicial del paciente consultante por pérdida de conciencia, podría ayudar al diagnóstico temprano de síncope vasovagal.

Abstract Introduction: Vasovagal syncope has an incidence between 10% and 19% in the general population, whose first episodes appear in youth. Objective: To estimate the prevalence of vasovagal syncope in a university student population from the southern Colombia, using a diagnostic questionnaire adapted from the Calgary Scale. Materials and methods: After voluntary signing of the informed consent form, students were surveyed through the Calgary Scale, and a subsequent follow-up questionnaire was conducted on positive participants. Results: 280 students participated in the study and 17% of them obtained a positive score for vasovagal syncope, being positive female participants the largest group. The mean age of participants was 21.45±5.18 years. At the follow-up, 10% of the positive cases had sought out treatment in emergency rooms because of consciousness loss, 4% were hospitalized, and 10% had secondary injuries. Conclusions: Even though an important number of patients was positive on the Calgary Scale, none of them had been diagnosed with neutrally mediated syncope, despite being treated in emergency rooms and/or presenting secondary lesions due to consciousness loss. The use of the Calgary Scale during the assessment of patients being treated for consciousness loss could help to early diagnose vasovagal syncope.

Syncope in patients with cardiac pacemakers

Abstract 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.

La Donación de Sangre / Blood donation

La donación de sangre es un procedimiento muy común en medicina, por eso tiene relevancia el estudio de las complicaciones frecuentes en los donantes y en especial las asociadas con la ferropenia. El procedimiento reporta beneficios tanto por la utilidad futura del producto como por los efectos favorables para la salud del donante; sin embargo, se han descrito complicaciones recurrentes derivadas tanto de la extracción de sangre total como de sus componentes por separado. En este artículo de revisión se encuentra la información relacionada con los factores de riesgo asociados con esta práctica y las principales complicaciones que pueden aparecer como es la depleción de hierro, con el fin de ilustrar al lector sobre los factores predisponentes en donantes iniciales y habituales. Se concluye que las reacciones más frecuentes son las vasovagales y algunas otras que pueden conllevar a síntomas indeseados, pero es la disminución de los niveles de hierro una de las complicaciones más alarmantes. Hay evidencia de factores como sexo, edad, nivel socioeconómico, dieta y tipo de sangre que favorecen la probabilidad de desarrollar complicaciones por deficiencia de hierro en los donantes.

Blood donation is a very common medical procedure, thus, it is important to review the most frequent complications indonors, especially blood-donation-induced iron deficiency. The procedure is beneficial both for the future usefulness of blood and blood products as well as the favorable health effects for the donors; however, recurrent complications derived from the collection of whole blood and blood components separately, have been described. This review article contains information related to the risk factors associated with this practice and the main complications that may appear, such as iron depletion, in order to enlighten the reader on the predisposing factors among first-time and repeat donors. It was concluded that vasovagal reactions are the most frequent reactions as well as other reactions that can lead to unwanted symptoms, but the decrease in iron levels is one of the most alarming complications. Sex, age, socioeconomic level, diet and blood type have been evidenced as factors that favor the probability of developing complications due to iron deficiency in donors.

Pediatric patients head-up-tilt-test with pharmacological challenge, it is safe? / Mesa inclinada en pacientes pediátricos con reto farmacológico, ¿es seguro?

Abstract Syncope in pediatrics represents an important cause of visits to the emergency units. For this reason, excluding a cardiac or malignant origin is essential at the time of the initial approach to determine what is the next step in management, or if they need to be referred to a pediatric cardiologist and/or electrophysiologist. Vasovagal syncope is the most frequent cause of syncope in pediatrics, in which a detailed clinical history is enough to make the diagnosis. If no diagnosis is concluded by the history, or if it is necessary to define the hemodynamic response of the patients, the head-up-tilt-test is indicated; this will trigger syncope due to an orthostatic stress caused by the angulated table (passive phase). If a negative response remains, it can be followed by a pharmacologic challenge to trigger the hemodynamic response, which is still controversial in pediatrics. The pharmacologic challenge increases the sensitivity with a slight reduction in test specificity. Although there is not a specific drug for the challenge in pediatric patients yet, the most commonly drugs used are nitrates and isoproterenol, the latter related to a great number of adverse effects. Sublingual administration of nitrates in the challenge has been proven to be ideal, effective, and safe in this specific age group. The aim of this article is to make a literature search to demonstrate the effectiveness and safety of the pharmacologic challenge during the head-up-tilt-test in pediatrics, emphasizing a study conducted at the National Institute of Cardiology with isosorbide dinitrate.

Resumen El síncope en edades pediátricas representa una causa importante en las visitas a unidades de urgencias, por lo que excluir un origen cardíaco o maligno es fundamental al momento del abordaje inicial para determinar la conducta a seguir o la necesidad de derivar al cardiólogo pediatra o electrofisiólogo. El síncope vasovagal (SVV) es la causa más frecuente de síncope en pediatría, para cuyo diagnóstico basta una historia clínica detallada. Cuando ésta no es suficiente para determinar el diagnóstico de síncope reflejo o es necesario definir el tipo de respuesta que lo origina, está indicada una prueba de mesa inclinada que produce un estrés ortostático por la angulación y ello desencadena un síncope (fase pasiva). En pruebas no concluyentes está indicado un reto farmacológico para precipitar la respuesta hemodinámica, pero aún es un tema de controversia en edades pediátricas. El reto farmacológico incrementa la sensibilidad de la prueba, con una ligera reducción de la especificidad. Si bien no existe todavía un medicamento específico para la población pediátrica, los más empleados son los nitratos y el isoproterenol, este último relacionado con un mayor número de efectos adversos. La administración sublingual de los nitratos utilizados ha demostrado ser ideal, efectiva y segura en los pacientes pediátricos. El objetivo del artículo es realizar una revisión de las publicaciones médicas que demuestran la efectividad y seguridad del reto farmacológico durante la prueba de mesa inclinada en pacientes pediátricos, con énfasis en un estudio conducido en el Instituto Nacional de Cardiología con dinitrato de isosorbida (DNIS).

Body mass index is a promising predictor of response to oral rehydration saline in children with vasovagal syncope / 中华医学杂志(英文版)

BACKGROUND@#Vasovagal syncope (VVS) greatly impairs quality of life. The therapeutic efficacy of oral rehydration saline (ORS) for unselected VVS patients is not satisfactory due to the diverse mechanisms of the disease. Body mass index (BMI) was demonstrated to reflect blood volume to a certain extent. Therefore, the present study explored the capability of BMI to predict the therapeutic response of children with VVS to ORS treatment.@*METHODS@#Seventy-four children with VVS who visited the Syncope Unit of Pediatrics at Peking University First Hospital from November 2010 to June 2019 receiving ORS treatment were enrolled for this retrospective case-control study. A comparison of demographic, clinical, and hemodynamic characteristics was performed between responders and non-responders. The correlation between baseline BMI and response time was analyzed. To determine the value of baseline BMI in predicting the therapeutic efficacy of ORS in children with VVS, a receiver operating characteristic curve analysis was performed.@*RESULTS@#Fifty-two children were identified as responders, and the remaining 22 children were identified as non-responders. The baseline BMI of the responders was much lower than that of the non-responders (16.4 [15.5, 17.8] kg/m2vs. 20.7 ±e6 kg/m2, P < 0.001), and baseline BMI was positively correlated with response time in the head-up tilt test after adjusting for sex (r = 0.256, 95% confidence interval [CI]: 0.067-0.439, P = 0.029). The area under the receiver operating characteristic curve of baseline BMI was 0.818 (95% CI: 0.704-0.932, P < 0.001), and an optimal cut-off value of 18.9 kg/m2 yielded a sensitivity of 83% and a specificity of 73% to predict the efficacy of ORS in VVS.@*CONCLUSION@#Prior to treatment, baseline BMI is a promising predictor of response to ORS in children with VVS.

Vasovagal syncope or postural orthostatic tachycardia syndrome in children with neurological symptoms at disease onset: a clinical analysis of 88 cases / 中国当代儿科杂志

OBJECTIVE@#To study the clinical features of vasovagal syncope (VVS) and postural orthostatic tachycardia syndrome (POTS) in children with neurological symptoms at disease onset.@*METHODS@#A retrospective analysis was performed on the medical data of 88 children with the initial symptoms of the nervous system, such as transient loss of consciousness, dizziness, headache, and convulsion, who were finally diagnosed with VVS or POTS.@*RESULTS@#Of the 88 children, there were 35 boys (40%) and 53 girls (60%), with an age of 4-15 years. The peak age of onset was between 10 and 13 years. All the children had the initial symptoms of transient loss of consciousness, dizziness, headache, and convulsion. Nervous system diseases were excluded by electroencephalography, cerebrospinal fluid examination, and cranial MRI. Of the 88 children, 53 (60%) were confirmed with VVS, and 35 (40%) with POTS, according to the results of head-up tilt test (HUTT). Five children with the initial symptom of transient loss of consciousness were misdiagnosed with epilepsy. Predisposing factors were determined for 59 children (67%), and prolonged standing was the most common factor, followed by change in body position and strenuous exercise. Premonitory symptoms were observed in 66 children (75%), among which chest discomfort was the most common symptom, followed by gastrointestinal symptoms (nausea, vomiting, and abdominal pain) and pale complexion. All 88 children received health education and exercise for autonomic nerve function, among whom 53 children with VVS were given oral rehydration salts and 35 children with POTS were given oral rehydration salts and metoprolol. All 88 children were followed up for 18 months, and the response rates to the above treatment at 3, 6, 12, and 18 months of follow-up were 87%, 93%, 93%, and 90% respectively.@*CONCLUSIONS@#In addition to nervous system diseases, functional cardiovascular diseases including VVS and POTS should be considered for children with the initial symptoms of transient loss of consciousness, dizziness, headache, and convulsion. HUTT can be used to make a confirmed diagnosis, and the early treatment can achieve a good outcome.

Síncope / Syncope

El síncope es una pérdida transitoria de conciencia y tono postural debido a hipoflujo sanguíneo cerebral que se recupera espontáneamente sin maniobras de RCP. En esta actualización se plantea el síncope vasovagal con sus diagnósticos diferenciales y posibles etiologías, fisiopatología y métodos de estudios. También se presenta la experiencia sobre este tema en nuestro hospital su estudio, tratamiento y diagnostico (tilt test) (AU)

Syncope is a transient loss of consciousness and postural tone due to cerebral blood hypoflow that recovers spontaneously without CPR maneuvers. This update discusses vasovagal syncope with its differential diagnoses and possible etiologies, pathophysiology, and diagnostic methods. Additionally, the experience on this topic of our hospital regarding investigations, treatment, and diagnosis is presented. (AU)

Polymorphisms in ß-adrenergic receptors are associated with increased risk to have a positive head-up tilt table test in patients with vasovagal syncope

Abstract Background Vasovagal syncope (VVS) is a frequent clinical condition in which a genetic background seems to be implicated. Considering that the adrenergic receptors (ARs) may play a role in VVS, the present study has as principal aim to determine if the α- and β-AR (ADRA and ADRB) gene polymorphisms are associated with an increased risk to have a positive head-up tilt table (HUTT) test in patients with VVS. Methods: Nine polymorphisms in the ADRA1A (rs1048101, rs1383914, rs574584, and rs573542), ADRB1 (rs1801252 and rs1801253), ADRB2 (rs1042713 and rs1042714), and ADRB3 (rs4994) genes were analyzed using the 5’ exonuclease TaqMan genotyping assay in a group of 134 patients with VVS. Results Under different models, the rs1801252 (OR = 8.63, 95% CI: 0.95-78.72, Precessive = 0.02), rs1042713 (OR = 1.94, 95% CI: 1.02-3.66, Padditive = 0.04), and rs4994 (OR = 2.46, 95% CI: 1.01-6.01, Pdominant = 0.042 and OR = 2.62, 95% CI: 1.04-6.63, Pover-dominant = 0.03) polymorphisms were associated with increased risk for a positive HUTT. All models were adjusted for statistically significant covariates. Conclusion These results suggest that some polymorphisms of the β-AR genes could contribute to a positive tilt test in patients with VVS.

Change in P wave on electrocardiogram and its diagnostic value in children and adolescents with cardioinhibitory vasovagal syncope / 中国当代儿科杂志

OBJECTIVE@#To study the change in P wave on electrocardiogram and its diagnostic value in children and adolescents with cardioinhibitory vasovagal syncope (VVS-CI).@*METHODS@#A total of 43 children and adolescents who were diagnosed with VVS-CI were enrolled as the VVS-CI group, and 43 healthy children and adolescents were enrolled as the control group. P wave duration and P wave voltage were measured by 12-lead electrocardiography in a basal state, and the changes were analyzed.@*RESULTS@#Compared with the control group, the VVS-CI group had a significantly lower heart rate (P<0.05) and significantly longer P wave duration (Pwd), P wave maximum duration (Pmax), and corrected P wave maximum duration (Pcmax), as well as significantly higher P wave dispersion (Pd) and corrected P wave dispersion (Pcd) (P<0.05). Pwd, Pmax, Pd, Pcmax and Pcd had a certain diagnostic value in children and adolescents with VVS-CI (P<0.05): Pwd had a sensitivity of 69.77% and a specificity of 83.72% at the optimal cut-off value of 78.49 ms; Pmax had a sensitivity of 76.74% and a specificity of 90.70% at the optimal cut-off value of 93.39 ms; Pd had a sensitivity of 95.35% and a specificity of 69.77% at the optimal cut-off value of 27.42 ms; Pcmax had a sensitivity of 46.51% and a specificity of 88.37% at the optimal cut-off value of 120.90 ms; Pcd had a sensitivity of 83.72% and a specificity of 72.09% at the optimal cut-off value of 36.37 ms.@*CONCLUSIONS@#Children and adolescents with VVS-CI have significantly increased Pwd, Pmax, Pd, Pcmax, and Pcd, which may indicate abnormal atrial electrical activity. The cut-off value of P wave has a certain diagnostic value in VVS-CI.

Gut microbiota analysis and its significance in vasovagal syncope in children / 中华医学杂志(英文版)

BACKGROUND@#Vasovagal syncope (VVS) is common in children and greatly affect both physical and mental health. But the mechanisms have not been completely explained. This study was designed to analyze the gut microbiota in children with VVS and explore its clinical significance.@*METHODS@#Fecal samples from 20 VVS children and 20 matched controls were collected, and the microbiota were analyzed by 16S rRNA gene sequencing. The diversity and microbiota compositions of the VVS cases and controls were compared with the independent sample t test or Mann-Whitney U test. The correlation between the predominant bacteria and clinical symptoms was analyzed using Pearson or Spearman correlation test.@*RESULTS@#No significant differences in diversity were evident between VVS and controls (P > 0.05). At the family level, the relative abundance of Ruminococcaceae was significantly higher in VVS children than in controls (median [Q1, Q3]: 22.10% [16.89%, 27.36%] vs. 13.92% [10.31%, 20.18%], Z = -2.40, P  4, P < 0.05). The relative abundance of Ruminococcaceae in VVS patients was positively correlated with the frequency of syncope (r = 0.616, P < 0.01). In terms of its correlation with hemodynamics, we showed that relative abundance of Ruminococcaceae was negatively correlated with the systolic and diastolic pressure reduction at the positive response in head-up tilt test (HUTT; r = -0.489 and -0.448, all P < 0.05), but was positively correlated with the mean pressure drop and decline rate (r = 0.489 and 0.467, all P < 0.05) as well as diastolic pressure drop and decline rate at the HUTT positive response (r = 0.579 and 0.589, all P < 0.01) in VVS patients.@*CONCLUSION@#Ruminococcaceae was the predominant gut bacteria and was associated with the clinical symptoms and hemodynamics of VVS, suggesting that gut microbiota might be involved in the development of VVS.