Objective: To investigate the predictive value of blood cell parameters in children with vasovagal syncope (VVS). Methods: In this case-control study, the VVS group included 111 patients with unexplained syncope or prodromata who were diagnosed with VVS by head-up tilt test in the Second Xiangya Hospital, Central South University from January 2018 to October 2020, and 111 healthy children were enrolled as control. The differences in blood cell parameters between the 2 groups were compared by t test and Mann-Whitney U test. Multivariate binary Logistic regression was used to analyze the independent correlation factors of VVS, and receiver operating characteristic (ROC) curve to explore the predictive value of blood cell parameters for diagnosing VVS. Results: Sex composition ratios were consistent in the 2 groups (51 males vs. 60 females), while the age of the VVS group was higher than that of the control group (11.0 (8.0, 12.5) vs. 8.0 (7.0, 11.0) years, Z=4.39, P<0.001). Compared with the control group, VVS group had lower level of white blood cell (WBC) (6.0 (5.3, 7.1)×10⁹ vs. 8.6 (6.7, 10.1)×10⁹/L, Z=-7.96, P<0.001), lymphocyte (LY) (2.3 (1.9, 2.7)×10⁹ vs. 4.0 (2.8, 6.3)×10⁹/L, Z=-8.49, P<0.001), lymphocyte ratio (0.39 (0.33, 0.44) vs. 0.52 (0.37, 0.69), Z=-5.59, P<0.001), monocyte (0.3 (0.3, 0.4)×10⁹ vs. 0.4 (0.3, 0.6)×10⁹/L, Z=-6.19, P<0.001), eosinophil (0.1 (0.1, 0.2)×10⁹ vs. 0.2 (0.2, 0.4)×10⁹/L, Z=-5.75, P<0.001), mean corpuscular-hemoglobin concentration (MCHC) ((328±12) vs. (333±11) g/L, t=-3.27, P<0.001) and blood platelet (263 (235, 313)×10⁹ vs. 341 (295, 409)×10⁹/L, Z=-2.69, P<0.001), but higher neutrophil ratio (0.53 (0.48, 0.58) vs. 0.37 (0.22, 0.54), Z=5.86, P<0.001), hematocrit (0.39±0.04 vs. 0.37±0.04, t=2.75, P=0.006), mean corpuscular volume (MCV) (85 (82, 88) vs. 81 (78, 84) fl, Z=5.56, P<0.001), mean corpuscular hemoglobin (28 (27, 29) vs. 27 (26, 28) pg, Z=3.39, P=0.001), red cell distribution width (39 (37, 41) vs. 37 (36, 40) fl, Z=4.02, P<0.001) and mean platelet volume (11 (10, 11) vs. 10 (9, 11) fl, Z=2.81, P=0.005) levels. After adjusting for confounding factors such as sex and age, LY (OR=0.42, 95%CI 0.29-0.62, P<0.001), WBC (OR=0.75, 95%CI 0.59-0.95, P=0.015), MCHC (OR=0.94, 95%CI 0.91-0.97, P<0.001) were independent negative correlation factors of VVS, while MCV (OR=1.08, 95%CI 1.01-1.15, P=0.021) was independent positive correlation factor. ROC curve showed that the combination of LY, WBC, MCV and MCHC had acceptable predictive value for the diagnosis of VVS, with area under curve of 0.88, sensitivity of 0.80, specificity of 0.83, and Youden index of 0.63. Conclusions: Compared with healthy children, the blood cell parameters usually change in those with VVS. Combination of LY, WBC, MCHC and MCV can facilitate the diagnosis of VVS in children with unexplained syncope or prodromata.
Case-Control Studies ; Child ; Female ; Humans ; Lymphocytes ; Male ; Syncope ; Syncope, Vasovagal/diagnosis* ; Tilt-Table Test

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 (SBP_CV), coefficient of variation of diastolic pressure (DBP_CV) and coefficient of variation of heart rate (HR_CV) 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 HR_CV,SBP_CV and DBP_CV 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 SBP_CV 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 SBP_CV 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 DBP_CV 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 DBP_CV 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 HR_CV 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 HR_CV 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 SBP_CV and HR_CV 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. SBP_CV ≥ 4.4% or HR_CV ≥ 10.5% of supine-erect position could be an indication of HUTT.
Blood Pressure ; Child ; Heart Rate ; Humans ; Orthostatic Intolerance/diagnosis* ; Postural Orthostatic Tachycardia Syndrome/diagnosis* ; Retrospective Studies ; Syncope, Vasovagal/diagnosis* ; Tilt-Table Test

Child ; Humans ; Syncope, Vasovagal/therapy* ; Tilt-Table Test

OBJECTIVE: To analyze the disease spectrums underlying orthostatic intolerance (OI) and sitting intolerance (SI) in Chinese children, and to understand the clinical empirical treatment options. METHODS: The medical records including history, physical examination, laboratory examination, and imagological examination of children were retrospectively studied in Peking University First Hospital from 2012 to 2021. All the children who met the diagnostic criteria of OI and SI were enrolled in the study. The disease spectrums underlying OI and SI and treatment options during the last 10 years were analyzed. RESULTS: A total of 2 110 cases of OI and SI patients were collected in the last 10 years, including 943 males (44.69%) and 1 167 females (55.31%) aged 4－18 years, with an average of (11.34±2.84) years. The overall case number was in an increasing trend over the year. In the OI spectrum, postural tachycardia syndrome (POTS) accounted for 826 cases (39.15%), followed by vasovagal syncope (VVS) (634 cases, 30.05%). The highest proportion of SI spectrum was sitting tachycardia (STS) (8 cases, 0.38%), followed by sitting hypertension (SHT) (2 cases, 0.09%). The most common comorbidity of OI and SI was POTS coexisting with STS (36 cases, 1.71%). The highest proportion of treatment options was autonomic nerve function exercise (757 cases, 35.88%), followed by oral rehydration salts (ORS) (687 cases, 32.56%), metoprolol (307 cases, 14.55%), midodrine (142 cases, 6.73%), ORS plus metoprolol (138 cases, 6.54%), and ORS plus midodrine (79 cases, 3.74%). The patients with POTS coexisting with VVS were more likely to receive pharmacological intervention than the patients with POTS and the patients with VVS (41.95% vs. 30.51% vs. 28.08%, χ²= 20.319, P < 0.01), but there was no significant difference in the proportion of treatment options between the patients with POTS and the patients with VVS. CONCLUSION POTS and VVS in children are the main underlying diseases of OI, while SI is a new disease discovered recently. The number of children with OI and SI showed an increasing trend. The main treatment methods are autonomic nerve function exercise and ORS. Children with VVS coexisting with POTS were more likely to take pharmacological treatments than those with VVS or POTS only.
Child ; Electrolytes ; Female ; Humans ; Male ; Metoprolol ; Midodrine ; Orthostatic Intolerance/therapy* ; Postural Orthostatic Tachycardia Syndrome/diagnosis* ; Retrospective Studies ; Salts ; Sitting Position ; Syncope, Vasovagal/diagnosis* ; Tilt-Table Test

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 (P<0.05). The coincidence rate of HR or HRD for the diagnosis of POTS in males was higher than that in females at 5 minutes of HUTT (P<0.05), while the coincidence rate of HR or HRD for the diagnosis of POTS in males was lower than that in females at 10 minutes of HUTT (P<0.05). The coincidence rate of HR for the diagnosis of POTS was higher in the >12 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.
Adolescent ; Blood Pressure ; Child ; Female ; Heart Rate ; Humans ; Male ; Postural Orthostatic Tachycardia Syndrome ; Tilt-Table Test

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.
Adolescent ; Child ; Child, Preschool ; Female ; Humans ; Male ; Postural Orthostatic Tachycardia Syndrome ; Posture ; Retrospective Studies ; Syncope, Vasovagal ; Tilt-Table Test

OBJECTIVE: To quantify the relationship between cerebral blood flow velocity and peripheral blood pressure during hypotension period, aiming to predict the brain hypotension before symptomatic occurrence. METHODS: Twenty vasovagal syncope (VVS) patients who had a previous clinical history were selected in groups and 20 pair-matched control subjects underwent 70° tilt-up test. The subjects remained supine for 30 minutes before recordings when Doppler probes, electrodes and Finapres device were prepared. After continuous baseline recordings for 10 min, the subjects underwent head up tilt (HUT) test (70°), and were standing upright for 30 minutes or until syncope was imminent. For ethical reasons, the subjects were turned back to supine position immediately after SBP dropped to ≥20 mmHg, when their consciousness persisted. The point of syncope was synchronized for all the subjects by the point SBP reached the minima. Their beat-to-beat blood pressures (BP) were recorded continuously and bilateral middle cerebral artery (MCA) flow velocities were obtained with two 2 MHz Doppler probes from a transcranial Doppler ultrasonography (TCD) system. A nonlinear dynamic method--multimodal pressure flow (MMPF) analysis was introduced to access cerebral autoregulation during different time intervals. We introduced a new indicator--syncope index (SI), which was extracted from blood flow velocity (BFV) signal to evaluate the variation of cerebral vascular tension, and could reflect the deepness of dicrotic notch in BFV signal. RESULTS: Compared with the syncope index of the baseline value at the beginning of the tilt test, SI in VVS group showed significantly lower when the VVS occurred (0.16±0.10 vs.0.27±0.10,P<0.01),while there was no significant difference in syncope index between the control group at the end of the tilt test and the baseline value at the beginning of the tilt test. For those VVS patients, pulse index and resistance index had no significant change. Syncope index decreased significantly 3 minutes before the point of syncope (0.23±0.07 vs.0.29±0.07,P<0.01). CONCLUSION Dynamic regulation is exhausted when vasovagal syncope occurred. Tension decrease of small vessels could have some relationship with loss of the cerebral autoregulation capability. The proposed syncope index could be a useful parameter in predicting syncope of VVS patients since it decreased significantly up to 3 minutes earlier from the point of syncope.
Blood Pressure ; Heart Rate ; Humans ; Nonlinear Dynamics ; Syncope ; Syncope, Vasovagal ; Tilt-Table Test

BACKGROUND AND PURPOSE: The objective of this study was to determine the patterns of blood pressure (BP) changes during the head-up tilt (HUT) test, particularly in terms of its clinical significance for patients with orthostatic hypotension (OH). METHODS: OH was divided into four categories based on systolic BP changes occurring within the first 10 minutes of the HUT test: sustained orthostatic hypotension (SOH), progressive orthostatic hypotension (POH), orthostatic hypotension with partial recovery (OHPR), and transient orthostatic hypotension (TOH). RESULTS: In total, 151 patients were analyzed: 65 with SOH, 38 with POH, 21 with OHPR, and 27 with TOH. POH patients exhibited the greatest reduction in systolic BP after HUT and were also the most likely to develop symptoms requiring early termination of the HUT test (42.1%, p < 0.001). Additionally, SOH patients exhibited smaller heart-rate variation with deep breathing values (p=0.003) and Valsalva ratios (p=0.022) compared to POH patients. The sweat volume was greatest in OHPR patients. CONCLUSIONS: Clinical characteristics, including the findings of autonomic function tests, differed between the OH patient groups. This might reflect differences in the underlying pathophysiologic mechanisms. Determining the patterns of BP changes during the HUT test may facilitate the development of effective management strategies in patients with OH.
Blood Pressure* ; Humans ; Hypotension, Orthostatic* ; Orthostatic Intolerance ; Respiration ; Sweat ; Tilt-Table Test

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.
Benign Paroxysmal Positional Vertigo ; Brain ; Child ; Dizziness* ; Electrocardiography ; Hematologic Tests ; Humans ; Hypotension, Orthostatic ; Incidence ; Magnetic Resonance Imaging ; Medical Records ; Meniere Disease ; Methods ; Migraine Disorders ; Pathology ; Physical Examination ; Postural Orthostatic Tachycardia Syndrome ; Retrospective Studies ; Tilt-Table Test ; Vertigo ; Vestibular Function Tests ; Vestibular Neuronitis

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.
Diagnosis ; Dizziness ; Humans ; Hypotension, Orthostatic ; Postural Orthostatic Tachycardia Syndrome ; Supine Position ; Tilt-Table Test ; Valsalva Maneuver