UNASSIGNED: Vasovagal syncope (VVS) and psychogenic pseudosyncope (PPS) can be difficult to distinguish, given their similar clinical presentations. This study was conducted to explore the clinical value of catecholamine levels in the differential diagnosis of VVS and PPS in children.
UNASSIGNED: This retrospective case-control study was conducted with data from children with VVS and PPS who underwent head-up tilt tests (HUTTs) at the Children\'s Hospital of Hebei Province between March 2021 and March 2023. The data collected were baseline clinical characteristics, HUTT results, serum catecholamine levels in the supine and upright positions, and 24 h urinary catecholamine concentrations. These variables were compared between the VVS and PPS groups.
UNASSIGNED: From 328 potentially eligible cases, 54 (16.46%) cases of VVS and 24 (7.32%) cases of PPS were included in the analysis. No significant difference in age, sex, body mass index, or syncope frequency was observed between the VVS and PPS groups. The main predisposing factors for syncope were body position changes in the VSS group (83.33%) and emotional changes in the PPS group (41.67%). The episode duration was significantly shorter in the VSS group than in the PPS group (4.01 ± 1.20 vs. 24.06 ± 5.56 min, p < 0.05). The recovery time was also shorter in the VVS group than in the PPS group (1.91 ± 0.85 vs. 8.62 ± 2.55 min, p < 0.05). Relative to patients with PPS, those with VVS had significantly higher serum epinephrine (EP) levels in the upright position [199.35 (102.88, 575.00) vs. 147.40 (103.55, 227.25), p < 0.05] and lower serum epinephrine levels in the supine position [72.70 (42.92, 122.85) vs. 114.50 (66.57, 227.50), p < 0.05].
UNASSIGNED: Serum EP levels have potential value in the differential diagnosis of VVS and PPS.

Tilt table testing (TTT) has been used for decades to study short-term blood pressure (BP) and heart rate regulation during orthostatic challenges. TTT provokes vasovagal reflex in many syncope patients as a background of widespread use. Despite the availability of evidence-based practice syncope guidelines, proper application and interpretation of TTT in the day-to-day care of syncope patients remain challenging. In this review, we offer practical information on what is needed to perform TTT, how results should be interpreted including the Vasovagal Syncope International Study classification, why syncope induction on TTT is necessary in patients with unexplained syncope and on indications for TTT in syncope patient care. The minimum requirements to perform TTT are a tilt table with an appropriate tilt-down time, a continuous beat-to-beat BP monitor with at least three electrocardiogram leads and trained staff. We emphasize that TTT remains a valuable asset that adds to history building but cannot replace it, and highlight the importance of recognition when TTT is abnormal even without syncope. Acknowledgement by the patient/eyewitness of the reproducibility of the induced attack is mandatory in concluding a diagnosis. TTT may be indicated when the initial syncope evaluation does not yield a certain, highly likely, or possible diagnosis, but raises clinical suspicion of (1) reflex syncope, (2) orthostatic hypotension (OH), (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT in the patient with a certain, highly likely or possible diagnosis of reflex syncope, may be to educate patients on prodromes. In patients with reflex syncope with OH TTT can be therapeutic to recognize hypotensive symptoms causing near-syncope to perform physical countermanoeuvres for syncope prevention (biofeedback). Detection of hypotensive susceptibility requiring therapy is of special value.

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.

An expert committee was formed to reach consensus on the use of Tilt Table Testing (TTT) in the diagnosis of disorders that may cause transient loss of consciousness (TLOC) and to outline when other provocative cardiovascular autonomic tests are needed. While TTT adds to history taking, it cannot be a substitute for it. An abnormal TTT result is most meaningful if the provoked event is recognised by patients or eyewitnesses as similar to spontaneous ones. The minimum requirements to perform TTT are a tilt table, a continuous beat-to-beat blood pressure monitor, at least one ECG lead, protocols for the indications stated below and trained staff. This basic equipment lends itself to perform (1) additional provocation tests, such as the active standing test carotid sinus massage and autonomic function tests; (2) additional measurements, such as video, EEG, transcranial Doppler, NIRS, end-tidal CO2 or neuro-endocrine tests; (3) tailor-made provocation procedures in those with a specific and consistent trigger of TLOC. TTT and other provocative cardiovascular autonomic tests are indicated if the initial evaluation does not yield a definite or highly likely diagnosis, but raises a suspicion of (1) reflex syncope, (2) the three forms of orthostatic hypotension (OH), i.e. initial, classic and delayed OH, as well as delayed orthostatic blood pressure recovery, (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT is to teach patients with reflex syncope and OH to recognise hypotensive symptoms and to perform physical counter manoeuvres.

An expert committee was formed to reach consensus on the use of tilt table testing (TTT) in the diagnosis of disorders that may cause transient loss of consciousness (TLOC) and to outline when other provocative cardiovascular autonomic tests are needed. While TTT adds to history taking, it cannot be a substitute for it. An abnormal TTT result is most meaningful if the provoked event is recognised by patients or eyewitnesses as similar to spontaneous events. The minimum requirements to perform TTT are a tilt table, a continuous beat-to-beat blood pressure monitor, at least one ECG lead, protocols for the indications stated below and trained staff. This basic equipment lends itself to the performance of (1) additional provocation tests, such as the active standing test, carotid sinus massage and autonomic function tests; (2) additional measurements, such as video, EEG, transcranial Doppler, NIRS, end-tidal CO2 or neuro-endocrine tests; and (3) tailor-made provocation procedures in those with a specific and consistent trigger of TLOC. TTT and other provocative cardiovascular autonomic tests are indicated if the initial evaluation does not yield a definite or highly likely diagnosis, but raises a suspicion of (1) reflex syncope, (2) the three forms of orthostatic hypotension (OH), i.e. initial, classic and delayed OH, as well as delayed orthostatic blood pressure recovery, (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT is to teach patients with reflex syncope and OH to recognise hypotensive symptoms and to perform physical counter manoeuvres.

Head-up tilt test (TT) has been used for >50 years to study heart rate/blood pressure adaptation to positional changes, to model responses to haemorrhage, to assess orthostatic hypotension, and to evaluate haemodynamic and neuroendocrine responses in congestive heart failure, autonomic dysfunction, and hypertension. During these studies, some subjects experienced syncope due to vasovagal reflex. As a result, tilt testing was incorporated into clinical assessment of syncope when the origin was unknown. Subsequently, clinical experience supports the diagnostic value of TT. This is highlighted in evidence-based professional practice guidelines, which provide advice for TT methodology and interpretation, while concurrently identifying its limitations. Thus, TT remains a valuable clinical asset, one that has added importantly to the appreciation of pathophysiology of syncope/collapse and, thereby, has improved care of syncopal patients.

Objective: We aimed to establish useful models for the clinical differential diagnosis between vasovagal syncope (VVS) and psychogenic pseudosyncope (PPS). Methods: This bicentric study included 176 patients (150 VVS and 26 PPS cases) for model development. Based on the results of univariate and multivariate analyses, a logistic regression model and a scoring model were established and their abilities to differentiate VVS from PPS were tested. Another 78 patients (53 VVS and 25 PPS) were used for external validation. Results: In the logistic regression model, the outcome indicated that the QT-dispersion (QTd) (P < 0.001), syncope duration (P < 0.001), and upright posture (P < 0.001) acted as independent factors for the differentiation of VVS from PPS, which generated an area under the curve (AUC) of 0.892. A cutoff value of 0.234 yielded a sensitivity and specificity of 89.3 and 80.8%, respectively, for the differentiation between VVS and PPS in the logistic regression model. In the scoring model which consists of three variables, a cutoff score of three points yielded a sensitivity and specificity of 91.3 and 76.9%, respectively, with an AUC of 0.909. The external validation test indicated that the negative and positive predictive values of the scoring model were 78.8 and 91.7%, respectively, and the accuracy was 80.8%. Conclusion: The scoring model consisting of three variables is an easy-to-perform, inexpensive, and non-invasive measure for initial differential diagnosis between VVS and PPS.

Psychogenic pseudosyncope (PPS) frequently mimics syncope. The aim of this study was to assess the prevalence and clinical features of PPS and its relationship to vasovagal syncope (VVS).
We examined retrospectively the medical records of 1,401 consecutive patients referred to a syncope unit. We identified patients who had the final diagnosis of PPS. In these patients, we retrieved the initial diagnosis made during their first visit and the subsequent tests performed leading to the final diagnosis.
Fourteen (1.0%) patients (mean age 35 ± 14; 11 females) were diagnosed as having PPS: seven had a diagnosis of PPS alone and seven had both VVS and PPS. High frequency of attacks (53 ± 35 attacks during the previous year), prolonged loss of consciousness (minutes to > 1 hour), and a history of psychiatric disorders characterized PPS patients. Tilt test reproduced a PPS attack in the presence of normal blood pressure and heart rate in seven patients (50%), and induced VVS in another three patients who had the final diagnosis of both PPS and VVS. In two patients, one or more events occurred during the clinic visits and were directly witnessed by the clinic personnel.
We have shown that 1% of referrals to a syncope unit have the final diagnosis of PPS and that up to 50% of cases presented with a different initial diagnosis, namely VVS. Our findings suggest that causality between syncope and psychiatric disorders is likely bidirectional. The presence of a multidisciplinary team is important to address this often unrecognized relationship.

The initial evaluation of patients with transient loss of consciousness (LOC) comprises a detailed medical history, physical examination, and 12-lead electrocardiogram. Because there are many causes of syncopal and nonsyncopal LOC, an adequate method of taking the clinical history, which is the cornerstone of diagnosing patients with transient LOC, should be used.

Psychogenic pseudosyncope (PPS) is the appearance of transient loss of consciousness (TLOC) in the absence of true loss of consciousness. Psychiatrically, most cases are classified as conversion disorder, which is hypothesized to represent the physical manifestation of internal stressors. The incidence of PPS is likely under-recognized and the disorder is under investigated in the unexplained syncope population, yet it can be diagnosed accurately with a focused history and confirmed with investigations including head-up tilt testing (HUTT), electroencephalogram (EEG; sometimes combined with video) or, in some centers, transcranial Doppler (TCD). Patients are more likely to be young females with an increased number of episodes over the past 6months. They frequently experience symptoms prior to their episodes including light-headedness, shortness of breath and tingling. Conversion disorder is associated with symptomatic chronicity, increased psychiatric and physical impairment, and diminished quality of life. Understanding the epidemiology, biological underpinnings and approach to diagnosis of PPS is important to improve the recognition of this disorder so that patients may be managed appropriately. The general treatment approach involves limiting unnecessary interventions, providing the patient with needed structure, and encouraging functionality. While there are no treatment data available for patients with PPS, studies in related conversion disorder populations support the utility of psychotherapy. Psychotropic medications should be considered in patients with comorbid psychiatric disorders.