Application of head-up tilt table testing in children

Differential Diagnosis Between Psychogenic Pseudosyncope and Vasovagal Syncope in Children: A Quantitative Scoring Model Based on Clinical Manifestations

The study was designed to explore a clinical manifestation-based quantitative scoring model to assist the differentiation between psychogenic pseudosyncope (PPS) and vasovagal syncope (VVS) in children. In this retrospective case-control study, the training set included 233 pediatric patients aged 5-17 years (183 children with VVS and 50 with PPS) and the validation set consisted of another 138 patients aged 5-15 years (100 children with VVS and 38 with PPS). In the training set study, the demographic characteristics and clinical presentation of patients were compared between PPS and VVS. The independent variables were analyzed by binary logistic regression, and the score for each variable was given according to the approximate values of odds ratio (OR) to develop a scoring model for distinguishing PPS and VVS. The cut-off scores and area under the curve (AUC) for differentiating PPS and VVS cases were calculated using receiver operating characteristic (ROC) curve. Then, the ability of the scoring model to differentiate PPS from VVS was validated by the true clinical diagnosis of PPS and VVS in the validation set. In the training set, there were 7 variables with significant differences between the PPS and VVS groups, including duration of loss of consciousness (DLOC) (p < 0.01), daily frequency of attacks (p < 0.01), BMI (p < 0.01), 24-h average HR (p < 0.01), upright posture (p < 0.01), family history of syncope (p < 0.05) and precursors (p < 0.01). The binary regression analysis showed that upright posture, DLOC, daily frequency of attacks, and BMI were independent variables to distinguish between PPS and VVS. Based on the OR values of each independent variable, a score of 5 as the cut-off point for differentiating PPS from VVS yielded the sensitivity and specificity of 92.0% and 90.7%, respectively, and the AUC value was 0.965 (95% confidence interval: 0.945-0.986, p < 0.01). The sensitivity, specificity, and accuracy of this scoring model in the external validation set to distinguish PPS from VVS were 73.7%, 93.0%, and 87.7%, respectively. Therefore, the clinical manifestation-based scoring model is a simple and efficient measure to distinguish between PPS and VVS.

The Application of Head-Up Tilt Test to Diagnose Hemodynamic Type of Orthostatic Intolerance in Children Aged Between 3 and 5 Years

Objectives: The head-up tilt test (HUTT) is a useful tool to assess autonomic function and to reproduce neurally mediated reflex. In this study, we evaluated the use of HUTT in pediatric patients aged 3-5 years with orthostatic intolerance. Materials and Methods: The medical history and HUTT records of 345 (180 males, aged from 3 to 5 years) cases of patients who complained of symptoms of orthostatic intolerance and who visited the Syncope Ward, Children's Medical Center, The Second Xiangya Hospital, Central South University from January 2003 to December 2019, were reviewed retrospectively. Results: Seventy-nine (22.9%) cases had positive responses to complete HUTT (basic HUTT and sublingual nitroglycerin HUTT), while 29 (8.4%) cases had positive responses if only basic HUTT was performed. Sublingual nitroglycerin provocation significantly increased the positive rate of the test (x 2= 27.565, P < 0.001). The most frequent hemodynamic response to HUTT was vasoinhibitory type vasovagal syncope (12.2%), Syncope (28.7%), and dizziness (22.6%) were the most common symptoms. Eight cases discontinued the test due to intolerable symptoms without severe adverse events occurring. Conclusions: HUTT was safe and well-tolerated and could be used to diagnose the hemodynamic type of orthostatic intolerance in children aged 3-5 years.

Children with transient loss of consciousness: Clinical characteristics and the effectiveness of diagnostic tests

BACKGROUND

Transient loss of consciousness (TLOC) is common among children and adolescents. The aims of this study were to identify clinical differences between patients with vasovagal syncope and those with epileptic seizures, which account for a large proportion of TLOC cases, and to evaluate the effectiveness of various diagnostic tests.

METHODS

The medical records of 160 children and adolescents with TLOC were analyzed retrospectively, and age, sex, clinical symptoms, and trigger factors were recorded. The cardiological and neurological evaluations performed included electrocardiograms, computed tomography scanning, magnetic resonance imaging, electroencephalograms (EEGs), echocardiograms, and head-up tilt tests (HUTTs). Overall assessments of the 160 patients generated final diagnoses.

RESULTS

The mean age of patients was 14.6 years old and TLOC occurred more frequently among girls (59.4%). The most common final diagnosis was vasovagal syncope (n = 102, 63.4%), followed by undetermined (n = 21, 13.1%) and epileptic seizures (n = 17, 10.6%). There were many other diagnoses, including cardiogenic syncope (1.3%). Patients diagnosed with vasovagal syncope were much more likely to have dizziness or light-headedness and blurred vision as pre-symptoms (p < 0.05), whereas patients diagnosed with epileptic seizures were more likely to have convulsions as an accompanying sign (p < 0.05). In addition, standing up was the most significant trigger factor for TLOC among those diagnosed with vasovagal syncope (p < 0.05). The sensitivity, specificity, and accuracy of the HUTT for vasovagal syncope were 95.1%, 75.0%, and 91.8%, respectively. Similarly, the sensitivity, specificity, and accuracy of EEGs for epileptic seizures were 80.0%, 70.6%, and 80.0%, respectively.

CONCLUSION

Vasovagal syncope and epileptic seizures should be considered as possible causes of most cases of TLOC in children and adolescents. An accurate case history and appropriate evaluation are essential for correct diagnoses.

The pathophysiology of vasovagal syncope

Vasovagal syncope, known also as neurogenic or neurocardiogenic syncope, accounts for about 30-40% of syncopes of unclear origin and is the most common type of syncope among children and adolescents. Vasovagal syncope is defined as a state of temporary loss of consciousness with reduction of muscle tone followed by sudden, rapid and total return of consciousness. Vasovagal syncope is caused by a drop in blood pressure and/or reflex bradycardia which occurs as a result of emotional or orthostatic stress. Consequently, in understanding the mechanism of neurogenic syncope, most attention is paid to the dysregulation of sympathetic-parasympathetic autonomic nervous system. The main objective of this study was to systematically review the pathomechanisms triggering a vasovagal reaction. The analysis is based on a review of the literature on this topic. Material was obtained using the library system ALEPH. The literature was obtained from databases such as PubMed, Medline and GBL. This study focused on the role of tilt testing in the diagnosis of vasovagal syncope as well as other tests used to assess the functioning of the autonomous control of the cardiovascular system in syncope.

2018 Chinese Pediatric Cardiology Society (CPCS) guideline for diagnosis and treatment of syncope in children and adolescents

Syncope belongs to the transient loss of consciousness (TLOC), characterized by a rapid onset, short duration, and spontaneous complete recovery. It is common in children and adolescents, accounting for 1% to 2% of emergency department visits.Recurrent syncope can seriously affect children's physical and mental health, learning ability and quality of life and sometimes cardiac syncope even poses a risk of sudden death. The present guideline for the diagnosis and treatment of syncope in children and adolescents was developed for guiding a better clinical management of pediatric syncope. Based on the globally recent development and the evidence-based data in China, 2018 Chinese Pediatric Cardiology Society (CPCS) guideline for diagnosis and treatment of syncope in children and adolescents was jointly prepared by the Pediatric Cardiology Society, Chinese Pediatric Society, Chinese Medical Association (CMA)/Committee on Pediatric Syncope, Pediatricians Branch, Chinese Medical Doctor Association (CMDA)/Committee on Pediatric Cardiology, Chinese College of Cardiovascular Physicians, Chinese Medical Doctor Association (CMDA)/Pediatric Cardiology Society, Beijing Pediatric Society, Beijing Medical Association (BMA). The present guideline includes the underlying diseases of syncope in children and adolescents, the diagnostic procedures, methodology and clinical significance of standing test and head-up tilt test, the clinical diagnosis vasovagal syncope, postural orthostatic tachycardia syndrome, orthostatic hypotension and orthostatic hypertension, and the treatment of syncope as well as follow-up.

Tilt angles and positive response of head-up tilt test in children with orthostatic intolerance

This study aimed at examining three tilt angle-based positive responses and the time to positive response in a head-up tilt test for children with orthostatic intolerance, and the psychological fear experienced at the three angles during head-up tilt test. A total of 174 children, including 76 boys and 98 girls, aged from 4 to 18 years old (mean 11.3±2.8 years old), with unexplained syncope, were randomly divided into three groups, to undergo head-up tilt test at the angles of 60°, 70° and 80°, respectively. The diagnostic rates and times were analysed, and Wong-Baker face pain rating scale was used to access the children's psychological fear. There were no significant differences in diagnostic rates of postural orthostatic tachycardia syndrome and vasovagal syncope at different tilt angles during the head-up tilt test (p>0.05). There was a significant difference, however, in the psychological fear at different tilt angles utilising the Kruskal-Wallis test (χ2=36.398, p<0.01). It was mildest at tilt angle 60° utilising the Kolmogorov-Smirnov test (p<0.01). A positive rank correlation was found between the psychological fear and the degree of tilt angle (r(s)=0.445, p<0.01). Positive response appearance time was 15.1±14.0 minutes at 60° for vasovagal syncope children. There was no significant difference in the time to positive response, at different tilt angles during the head-up tilt test for vasovagal syncope or for postural orthostatic tachycardia syndrome. Hence, it is suggested that a tilt angle of 60° and head-up tilt test time of 45 minutes should be suitable for children with vasovagal syncope.

A clinical manifestation-based prediction of haemodynamic patterns of orthostatic intolerance in children: a multi-centre study

OBJECTIVE

At present, the haemodynamic diagnosis of orthostatic intolerance is based mainly on the head-up tilt table test, which is sometimes risky for patients. Thus, it is important to find objective and safe methods to differentiate haemodynamic patterns of orthostatic intolerance cases.

METHODS

In all, 629 children with orthostatic intolerance, either vasovagal syncope or postural orthostatic tachycardia syndrome, were included in the multi-centre clinical study. We analysed the association between the clinical manifestation and haemodynamic patterns of the patients.

RESULTS

Syncope after motion with a prodrome of chest distress or palpitations and the concomitant symptom(s) after a syncopal attack, with debilitation, dizziness or headache, were the most important variables in predicting the diagnosis of vasovagal syncope. The overall diagnostic accuracy was 71.5%.

CONCLUSION

Complaint of syncope after motion with prodromal chest distress or palpitation and the concomitant symptom after a syncopal attack, with subsequent debilitation, dizziness or headache, were the most important variables in the diagnosis of vasovagal syncope in children with orthostatic intolerance.

Orthostatic symptoms does not always manifest during tilt-table test in pediatric postural orthostatic tachycardia syndrome patients

Purpose

Chronic day-to-day symptoms of orthostatic intolerance are the most notable features of postural orthostatic tachycardia syndrome (POTS). However, we have encountered patients with such symptoms and excessive tachycardia but with no symptoms during the tilt-table test (TTT). We aimed to investigate whether POTS patients with chronic orthostatic intolerance always present orthostatic symptoms during the TTT and analyze the factors underlying symptom manifestation during this test.

Methods

We retrospectively examined patients who presented with POTS at the Gyeongsang National University Hospital between 2008 and 2011. Diagnosis of POTS was based on chronic day-to-day orthostatic intolerance symptoms as well as excessive tachycardia during the TTT. The patients were divided two groups depending on the presentation of orthostatic symptoms during the TTT. Clinical data and the results of the TTT were compared between these groups.

Results

In 22 patients, 7 patients (31.8%) did not present orthostatic symptoms during the test. Diastolic blood pressure (BP) was significantly lower in the symptom-positive group. The head-up tilt resulted in a significant increase in diastolic BP in the symptom-negative group (P=0.04), while systolic BP had a tendency to decrease in the symptom-positive group (P=0.06).

Conclusion

Significant patients with POTS did not present orthostatic symptoms during the TTT despite having chronic daily symptoms. This finding may be important for establishing definitive diagnostic criteria for pediatric POTS. Development of symptoms during TTT might be related to low diastolic BP and abnormal compensatory responses to orthostasis.