Factores que dificultan el diagnóstico del síndrome de taquicardia ortostática postural / Factors that hinder the diagnosis of postural orthostatic tachycardia syndrome

Las disautonomías son el resultado de un mal funcionamiento del sistema nervioso autónomo, entre las cuales se encuentra el síndrome de taquicardia ortostática postural, un problema de salud variable y complejo que tiene una prevalencia considerable, principalmente en adolescentes y mujeres. Este produce una amplia variedad de signos y síntomas que son similares a los de otras patologías, lo que, sumado a la falta de pruebas diagnósticas específicas, muchas veces retrasa el diagnóstico. A pesar de la existencia de criterios estandarizados para determinar la presencia del síndrome, existe aún una brecha en el conocimiento acerca del mismo. Esto dificulta el abordaje del padecimiento y, por consiguiente, su tratamiento oportuno. Conocer más sobre este síndrome y los factores que dificultan su diagnóstico temprano permitiría mejorar la atención de los pacientes y su calidad de vida

Dysautonomias are the result of a malfunction of the autonomic nervous system, among which is the postural orthostatic tachycardia syndrome, a variable and complex health problem that has a considerable prevalence, mainly in adolescents and women. It produces a wide variety of signs and symptoms that are similar to those of other pathologies, which, added to the lack of specific diagnostic tests, often delays diagnosis. Despite the existence of standardized criteria to determine the presence of the syndrome, there is still a gap in knowledge about it. This hinders the approach to the condition and, consequently, its timely treatment. Understanding more about this syndrome and the factors that hinder its early diagnosis would improve patient care and quality of life

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.

Acrocianosis como primera manifestación de síndrome de taquicardia postural ortostática en dos adolescentes / Acrocyanosis as the first manifestation of orthostatic postural tachycardia syndrome in two adolescents

La acrocianosis desencadenada por la bipedestación como signo principal de la taquicardia postural ortostática (POTS, por su sigla en inglés) es poco conocida, aunque bien descrita en la bibliografía especializada. Se describen dos casos clínicos de adolescentes que consultaron en el Servicio de Urgencias por acrocianosis e intolerancia al ortostatismo. El primer paciente, de 13 años, presentó un aumento de la frecuencia cardíaca de 40 latidos por minuto (lpm) al pasar del decúbito a la bipedestación. El segundo, de 14 años, presentó un aumento de la frecuencia cardíaca hasta 125 lpm al incorporarse. En ambos, la tensión arterial y los estudios complementarios fueron normales. El POTS se define en la edad pediátrica como una intolerancia al ortostatismo que se acompaña de aumento de la frecuencia cardíaca excesiva sin hipotensión arterial. Conocer la acrocianosis como primer signo de presentación es de utilidad para el diagnóstico de esta enfermedad y para evitar estudios complementarios innecesarios.

Acrocyanosis triggered by standing position as the main sign of postural orthostatic tachycardia (POTS) is little known but well described in scientific literature. In pediatric age, POTS is defined as orthostatic intolerance that is accompanied by an excessive increase in heart rate without arterial hypotension. We present two clinical reports of teenagers who were admitted in the Emergency Department with acrocyanosis and orthostatic intolerance. The first patient was 13-year-old and had an increase in heart rate of 40 bpm when moving from a reclining to a standing position. The second patient was 14-year-old and showed an increasing in heart rate up to 125 bpm after upright position. In both patients' blood pressure was normal and all investigations were negative. They were finally diagnosed with postural orthostatic tachycardia. Recognizing acrocyanosis as first sign of this disease is useful for diagnosis and can help to avoid unnecessary testing.

Baseline left ventricular ejection fraction associated with symptom improvements in both children and adolescents with postural tachycardia syndrome under metoprolol therapy / 中华医学杂志(英文版)

BACKGROUND@#Postural tachycardia syndrome (POTS) is a common childhood disease that seriously affects the patient's physical and mental health. This study aimed to investigate whether pre-treatment baseline left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) values were associated with symptom improvement after metoprolol therapy for children and adolescents with POTS.@*METHODS@#This retrospective study evaluated 51 children and adolescents with POTS who received metoprolol therapy at the Peking University First Hospital between November 2010 and July 2019. All patients had completed a standing test or basic head-up tilt test and cardiac echocardiography before treatment. Treatment response was evaluated 3 months after starting metoprolol therapy. The pre-treatment baseline LVEF and LVFS values were evaluated for correlations with decreases in the symptom score after treatment (ΔSS). Multivariable analysis was performed using factors with a P value of  0.050). However, responders had significantly higher baseline LVEF (71.09% ± 4.44% vs. 67.17% ± 4.88%, t = -2.789, P = 0.008) and LVFS values (40.00 [38.00, 42.00]% vs. 36.79% ± 4.11%, Z = -2.542, P = 0.010) than the non-responders. The baseline LVEF and LVFS were positively correlated with ΔSS (r = 0.378, P = 0.006; r = 0.363, P = 0.009), respectively. Logistic regression analysis revealed that LVEF was independently associated with the response to metoprolol therapy in children and adolescents with POTS (odds ratio: 1.201, 95% confidence interval: 1.039-1.387, P = 0.013).@*CONCLUSIONS@#Pre-treatment baseline LVEF was associated with symptom improvement after metoprolol treatment for children and adolescents with POTS.

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.

Efficiency of heart rate and heart rate difference at different time points during head-up tilt test in the diagnosis of postural tachycardia syndrome in children and adolescents / 中国当代儿科杂志

OBJECTIVE@#To study the efficiency of heart rate (HR) and heart rate difference (HRD) at different time points during head-up tilt test (HUTT) in the diagnosis of postural tachycardia syndrome (POTS) in children and adolescents.@*METHODS@#A total of 217 children and adolescents, aged 6-16 years, who were diagnosed with POTS were enrolled as the POTS group, and 73 healthy children and adolescents, matched for sex and age, were enrolled as the control group. The POTS group was further divided into ≤12 years old group with 127 children/adolescents and >12 years old group with 90 children/adolescents. The two groups were compared in terms of HR at baseline and at 5 and 10 minutes of HUTT (HR0, HR5, and HR10 respectively), difference between HR5/HR10 and HR0 (HRD5 and HRD10 respectively). The efficiency of HR5, HR10, HRD5 and HRD10 in the diagnosis of POTS was assessed.@*RESULTS@#Compared with the control group, the POTS group had significant increases in HR5, HR10, HRD5, and HRD10 (P12 years old subgroup (P<0.05), while the coincidence rate of HRD for the diagnosis of POTS was higher in the ≤12 years old subgroup (P<0.05). The combination of HR5, HR10, HRD5, and HRD10 for the diagnosis of POTS had a greater area under the curve (0.974; 95%CI: 0.949-0.989) than HR5, HR10, HRD5, or HRD10 alone, with a sensitivity of 87.80% and a specificity of 95.83%. The diagnostic efficacy of HRD for POTS was higher than that of HR (P<0.05).@*CONCLUSIONS@#HR and HRD at different time points during HUTT have a good value in the diagnosis of POTS in children and adolescents, and the accuracy of diagnosis varies with age and gender.

Hemodynamic changes in standing-up test of children and adolescents with postural tachycardia syndrome / 北京大学学报(医学版)

OBJECTIVE@#To explore the hemodynamic changes in standing-up test of children and adolescents with postural tachycardia syndrome (POTS) and to compare hemodynamic parameters of POTS patients with decreased cardiac index (CI) and those with not-decreased CI.@*METHODS@#A retrospective study was conducted to show the trends of CI, total peripheral vascular resistance index (TPVRI), heart rate and blood pressure in standing-up test of 26 POTS patients and 12 healthy controls, and to compare them between the two groups. The POTS patients were divided into two groups based on CI decreasing or not in standing-up test, namely decreased CI group (14 cases) and not-decreased CI group (12 cases). The trends of the above mentioned hemodynamic parameters in standing-up test were observed and compared between decreased CI group and not-decreased CI group.@*RESULTS@#In standing-up test for all the POTS patients, CI (F=6.936, P=0.001) and systolic blood pressure (F=6.049, P<0.001) both decreased significantly, and heart rate increased obviously (F=113.926, P<0.001). However, TPVRI (F=2.031, P=0.138) and diastolic blood pressure (F=2.018, P=0.113) had no significant changes. For healthy controls, CI (F=3.646, P=0.016), heart rate (F=43.970, P<0.001), systolic blood pressure (F=4.043, P=0.020) and diastolic blood pressure (F=8.627, P<0.001) all increased significantly in standing-up test. TPVRI (F=1.688, P=0.190) did not change obviously. The changing trends of CI (F=6.221, P=0.001), heart rate (F=6.203, P<0.001) and systolic blood pressure (F=7.946, P<0.001) over time were significantly different between the patients and healthy controls, however, no difference was found in TPVRI and diastolic blood pressure (P > 0.05). Among the POTS patients, CI was significantly different between decreased CI group and not-decreased CI group (F=14.723, P<0.001). Systolic blood pressure of the former decreased obviously (F=8.010, P<0.001), but it did not change obviously in the latter (F=0.612, P=0.639). Furthermore, none of the changes of TPVRI, heart rate and diastolic blood pressure in standing-up test were significantly different between the two groups (P > 0.05). Age was an independent factor for decreased CI patients (P=0.013, OR=2.233; 95% CI, 1.183 to 4.216).@*CONCLUSION@#POTS patients experience vital hemodynamic changes in standing-up test, part of them suffering from decreased CI, but others from not-decreased CI. Age is an independent factor for patients suffering from decreased CI.

2018 KHRS guideline for the evaluation and management of syncope: Part 2

The general concept and initial approach to syncope patients has been mentioned in the general sections. This special sections have been described the characteristics, diagnosis, and treatment with patient education for the each syncope. It has been described in order of reflex syncope, orthostatic hypotension, postural orthostatic tachycardia syndrome (POTS), cardiac syncope, and unexplained syncope. Several clinical issues will have been dealt with in special issues. Neurological assessment is added when the patients were diagnosed with psychogenic pseudosyncope (PPS). Although many childhood syncope caused by reflex syncope, they are also presented as syncope caused by arrhythmic events in patients with congenital heart disease. In the elderly patients, syncope is because of not only a single cause of syncope but a combination of various conditions. In case of a syncope patient visiting the emergency department, a standardized systematic approach will be required to determine whether hospitalize the patient according to the risk of recurrence and the needs for the syncope management unit. We also mention recommendations on the limits of driving, exercising and social life style that are relevant to syncope in all patients. In this guideline, we reviewed the Korean published literatures and European/American guidelines on syncope. We, writing and publishing committee for evaluation and management guidelines of syncope in the Korean Society for Holter and Noninvasive Electrocardiography (KSHNE) under the Korean Heart Rhythm Society (KHRS) are very pleased to be able to publish this guideline. We also hope this guideline will be a good support to manage the syncope patients and a useful trigger for further research in Korea.

Etiology and Clinical Characteristics of Pediatric Dizziness / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Dizziness is not uncommon in children. The etiology of dizziness varies according to different studies due to different methods of examination or characteristics of the dizziness center. To assess meaningful causes of dizziness in children, a multidisciplinary approach would be needed. The purpose of this study was to analyze the main pathologies associated with vertigo and dizziness in children, paying particular attention to recent diagnostic advances with a multidisciplinary approach. SUBJECTS AND METHOD: A total of 73 children, aged between 4-18 years, who visited the Pediatric Dizziness Clinic of the University Hospital from January 2016 to June 2016 were included in this study. Medical records were reviewed retrospectively. All of the subjects were examined by history, questionnaires, physical examinations, electrocardiogram, hematologic tests, brain MRI scan, audiogram and vestibular function tests. Patients who had orthostatic symptoms additionally underwent a tilt table test, and in selective cases, a caloric and vestibular evoked myogenic potential tests as well. RESULTS: Vestibular migraine (VM) and benign paroxysmal vertigo of childhood (BPVC) were found in 35.6% and 27.4% of the children with dizziness, respectively. The incidence of orthostatic hypotension and postural orthostatic tachycardia syndrome were 12.3% each, both of which are higher than other previous reports. Other causes were Meniere's disease, benign paroxysmal positional vertigo, vestibular neuritis and so on. CONCLUSION: VM and BPVC were the most common causes of pediatric dizziness. Also, the incidence of orthostatic dizziness was rather high in pediatric population. The evaluation of dizziness in children should include a thorough check of history (questionnaire), neurotological examination, vestibular function tests and a tilt table test.

Small Fiber Neuropathy and Postural Orthostatic Tachycardia Syndrome after Human Papillomavirus Vaccination

We describe a 44-year-old woman with paresthesia, fatigue, and palpitation, 10 days after human papillomavirus (HPV) vaccination. The quantitative sensory test showed abnormal detection threshold in her foot. Tilt test result indicated postural orthostatic tachycardia syndrome. Symptoms were improved after immunomodulating therapy, pain control drug, and oral beta blocker medication. This is first case report for small fiber neuropathy and autonomic dysfunction after HPV vaccination in Korea.

Autonomic Dysfunction in Dizziness Clinic / 대한평형의학회지

Orthostatic dizziness is a common type of dizziness. In general, orthostatic dizziness is provoked by standing or tilting, and subsided by supine position. The patient with orthostatic intolerance complains multiple symptoms such as dizziness, palpitation, lightheadness, fatigue and rarely syncope. Common orthostatic intolerance is orthostatic hypotension (classic, initial, transient, and delayed orthostatic hypotension) and postural orthostatic tachycardia syndrome. Transcranial Doppler is a noninvasive technique that provides real-time measurement of cerebral blood flow velocity. It can be useful for understanding the relationship between orthostatic symptoms and cerebral autoregulatory function. The reciprocal causal relationship between vestibular and autonomic dysfunction should always be kept in mind.

Evaluation of Adrenergic Function: Tilt-Table and Valsalva Test / 대한평형의학회지

Orthostatic dizziness is a common dizziness syndrome characterized by nonvertiginous lightheadedness when patients rise to stand from a sitting or supine position. Orthostatic dizziness is commonly believed to derive from orthostatic hypotension (OH) or postural tachycardia syndrome (POTS). Tilt-table test and Valsalva maneuver are standardized methods for evaluating of adrenergic autonomic function and essential for diagnosis of OH and POTS. We described the guidelines and interpretations of the tilt-table test and Valsalva maneuver.

Desafios diagnósticos na Síndrome da Taquicardia Postural Ortostática (POTS) em uma adolescente / Challenges on the diagnostis of Postural Orthostatic Tachycardia Syndrome (POTS) in a adolescent patient

Descreveu-se a Síndrome da Taquicardia Postural Ortostática (POTS) em uma adolescente de 16 anos, com história de 10 anos de hipotireoidismo e episódio de síncope incompleta e sintomas disautonômicos flutuantes por seis meses. Após esses seis meses, a paciente apresentou novo episódio de síncope incompleta pós-prandial. Apesar de um Tilt Test não ter flagrado anormalidade, em duas ocasiões separadas, flagramos aumentos ortostáticos da frequência cardíaca de 43 e 40 bpm, sem queda significativa da pressão arterial. Além de hipotireoidismo, não se detectaram outros fatores de risco para disautonomia. Propranolol (10mg, 12/12h) controlou os sintomas. POTS é de difícil. (AU)

We describe the Postural Orthostatic Tachycardia Syndrome (POTS) in a 16-year-old girl with a 10-year history of hypothyroidism who experienced an incomplete syncope episode with fluctuating disautonomic symptoms for 6 months. After six months, the patient had a new postprandial incomplete syncope episode. Although a Tilt Test did not disclose abnormality, in two separate occasions, we documented a heart rate increase of 43 and 40 bpm after standing, without a significant drop in blood pressure. Other than hypothyroidism, we did not detect other risk factors for dysautonomia. Propranolol (10mg, 12 / 12h) controlled the symptoms. POTS is difficult to diagnose in adolescents. It is often confused with Epilepsy and Neurocardiogenic Syncope, which may result from hypothyroidism. (AU)

Application of Near-Infrared Spectroscopy in Neurological Disorders: Especially in Orthostatic Intolerance

Near-infrared spectroscopy (NIRS), a noninvasive optical method, utilizes the characteristic absorption spectra of hemoglobin in the near-infrared range to provide information on cerebral hemodynamic changes in various clinical situations. NIRS monitoring have been used mainly to detect reduced perfusion of the brain during orthostatic stress for three common forms of orthostatic intolerance (OI); orthostatic hypotension, neurally mediated syncope, and postural orthostatic tachycardia syndrome. Autonomic function testing is an important diagnostic test to assess their autonomic nervous systems for patients with symptom of OI. However, these techniques cannot measure dynamic changes in cerebral blood flow. There are many experimentations about study of NIRS to reveal the pathophysiology of patients with OI. Research using NIRS in other neurologic diseases (stroke, epilepsy and migraine) are ongoing. NIRS have been experimentally used in all stages of stroke and may complement the established diagnostic and monitoring tools. NIRS also provide pathophysiological approach during rehabilitation and secondary prevention of stroke. The hemodynamic response to seizure has long been a topic for discussion in association with the neuronal damage resulting from convulsion. One critical issue when unpredictable events are to be detected is how continuous NIRS data are analyzed. Besides, NIRS studies targeting pathophysiological aspects of migraine may contribute to a deeper understanding of mechanisms relating to aura of migraine. NIRS monitoring may play an important role to trend regional hemodynamic distribution of flow in real time and also highlights the pathophysiology and management of not only patients with OI symptoms but also those with various neurologic diseases.

Syndromes of Orthostatic Intolerance: Pathophysiology and Diagnosis

Orthostasis means standing upright. Thus, orthostatic intolerance (OI) can be simply defined as “the development of symptoms during upright standing, that are relieved by recumbency.” However, OI might be a confusing topic in clinical practice because of the recent appreciation of the condition's clinical variant, emerging understanding of its diverse mechanisms, and its nomenclature, which seems to change annually. OI is not fatal but should be differentiated from potentially lethal disorders, including seizures or cardiogenic syncope. Typical signs and symptoms include loss of consciousness, lightheadedness, and visual difficulties. However, patients also experience multiple and nonspecific symptoms that seem unrelated to orthostatic intolerance, such as headache, fatigue, nausea, abdominal pain, and exercise intolerance. This review was aimed at expanding the comprehension of this confusing and easily missed topic by providing better understanding of the normal hemodynamic response to orthostasis and the basic pathophysiological concepts of major syndromes of OI.

Orthostatic Hypotension and Postural Orthostatic Tachycardia Syndrome in Children: Comparison of Clinical Features and Neurophysiology Test

PURPOSE: The clinical characteristics and neuropsychological tests of orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS) in children were compared. METHODS: From August 2011 to April 2015, we enrolled patients who visited hospital with dizziness or syncope. According to the results of head-up tilt test (HUTT), the patients were classified into 4 groups; OH group, POTS group, normal group I who had no orthostatic symptom during HUTT, and normal group II who had orthostatic symptom during HUTT. RESULTS: Eighty-eight patients were enrolled with 11(12.5%) in OH group, 13(14.7%) in POTS group, 49(55.7%) in normal group I and 15(17.0%) in the normal group II. During HUTT, the temporal changes of systolic, diastolic, and mean blood pressure of OH group were significantly different from those of POTS group, normal group I, and normal group II. Heart rate changes after tilt showed increase trend in all 4 groups and there was no significant different between OH and POTS group. In normal group II, the temporal changes of diastolic and mean blood pressure were similar to those in POTS group and were significantly different from normal group I. In the autonomic nervous system test, the heart rate response to deep breathing (HRDB) was significantly different between normal group I and II CONCLUSIONS: In pediatric OH patients, heart rate may be increased with blood pressure fall. And if orthostatic symptoms are associated with HUTT, we should not exclude OI even if the test result do not meet the criteria for diagnosis.

Pathogenesis and Individualized Treatment for Postural Tachycardia Syndrome in Children / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>Postural tachycardia syndrome (POTS) is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS in children.</p><p><b>DATA SOURCES</b>The data analyzed in this review are mainly from articles included in PubMed and EMBASE.</p><p><b>STUDY SELECTION</b>The original articles and critical reviews about POTS were selected for this review.</p><p><b>RESULTS</b>Studies have shown that POTS might be related to several factors including hypovolemia, high catecholamine status, abnormal local vascular tension, and decreased skeletal muscle pump activity. In addition to exercise training, the first-line treatments mainly include oral rehydration salts, beta-adrenoreceptor blockers, and alpha-adrenoreceptor agonists. However, reports about the effectiveness of various treatments are diverse. By analyzing the patient's physiological indexes and biomarkers before the treatment, the efficacy of medication could be well predicted.</p><p><b>CONCLUSIONS</b>The pathogenesis of POTS is multifactorial, including hypovolemia, abnormal catecholamine state, and vascular dysfunction. Biomarker-directed individualized treatment is an important strategy for the management of POTS children.</p>

Orthostatic Intolerance Syndrome

Orthostatic intolerance is the inability to tolerate an upright posture as a consequence of varying degrees of autonomic nervous system dysfunction. Orthostatic intolerance syndromes can be classified into at least 3 categories: 1) orthostatic hypotension, 2) neurally mediated (reflex) syncope, and 3) postural orthostatic tachycardia syndrome. In this review, we discuss the pathophysiology and etiologies of orthostatic hypotension and postural orthostatic tachycardia syndrome, and propose their diagnostic and therapeutic alternatives.

Inappropriate Sinus Tachycardia

Since inappropriate sinus tachycardia (IST) occurs due to various reasons, it can be diagnosed after exclusion of all causes and diseases that may result in sinus tachycardia. In particular, it is important to differentiate postural orthostatic tachycardia syndrome (POTS), and a multidisciplinary approach is necessary for differentiating psychiatric events. In addition, whether the clinical symptoms coincide with tachycardia events should be checked before treatment. β-adrenergic blocker is the most effective drug, and exercise training is recommended for controlling clinical symptoms. Furthermore, discontinuation of smoking and alcohol consumption, and decrease in caffeine intake may be useful. Recently, ivabradine has been found effective, and catheter ablation can be considered in cases of drug refractory IST presenting with clinical symptoms.

Dermatological Manifestations of Postural Tachycardia Syndrome Are Common and Diverse

BACKGROUND AND PURPOSE: Postural tachycardia syndrome (POTS) is a syndrome of orthostatic intolerance in the setting of excessive tachycardia with orthostatic challenge, and these symptoms are relieved when recumbent. Apart from symptoms of orthostatic intolerance, there are many other comorbid conditions such as chronic headache, fibromyalgia, gastrointestinal disorders, and sleep disturbances. Dermatological manifestations of POTS are also common and range widely from livedo reticularis to Raynaud's phenomenon. METHODS: Questionnaires were distributed to 26 patients with POTS who presented to the neurology clinic. They were asked to report on various characteristics of dermatological symptoms, with their answers recorded on a Likert rating scale. Symptoms were considered positive if patients answered with "strongly agree" or "agree", and negative if they answered with "neutral", "strongly disagree", or "disagree". RESULTS: The most commonly reported symptom was rash (77%). Raynaud's phenomenon was reported by over half of the patients, and about a quarter of patients reported livedo reticularis. The rash was most commonly found on the arms, legs, and trunk. Some patients reported that the rash could spread, and was likely to be pruritic or painful. Very few reported worsening of symptoms on standing. CONCLUSIONS: The results suggest that dermatological manifestations in POTS vary but are highly prevalent, and are therefore of important diagnostic and therapeutic significance for physicians and patients alike to gain a better understanding thereof. Further research exploring the underlying pathophysiology, incidence, and treatment strategies is necessary.