Head-up Tilt Test In Children Research Articles

Isolated very low QRS voltage in at least one frontal lead is associated with vasovagal syncope in children.

To assess whether isolated very low QRS voltage of ≤0.3 mV in the frontal leads might be a marker for diagnosing paediatric vasovagal syncope and the risk of recurrence. We included 118 children with vasovagal syncope, comprising 70 males and 48 females in our retrospective analysis. All patients underwent head-up tilt test and supine 12-lead electrocardiography. Furthermore, the QRS voltage was measured from each one of the 12 leads on basal electrocardiography. Patients were followed up for 6-24 months (average, 16 months). Eighty-six patients (73%) patients displayed isolated very low QRS voltage in frontal leads. Furthermore, the patients were classified into two groups based on the presence or absence of isolated very low QRS voltage. Enhanced syncopic spells over the past 6 months, and the positive rates of head-up tilt test were observed in patients having isolated very low QRS voltage in the frontal leads than those without isolated very low QRS voltage (p < 0.05). The single factor and time-to-event analyses also showed an increased syncope recurrence rate in patients with isolated very low QRS voltage in frontal leads when compared with those without isolated very low QRS voltage (p < 0.01). Isolated very low QRS voltage in frontal leads is correlated with the positive response of the head-up tilt test in children who experience syncope and its recurrence post-treatment. Hence, isolated very low QRS voltage in frontal leads might become a novel diagnostic indicator and a risk factor for syncope recurrence in children with vasovagal syncope.

Clinical characteristics and hemodynamic responses to head-up tilt test in children and adolescents with unexplained sighing.

Sighing is a common symptom in children and adolescents. In this study, we explored the clinical characteristics and hemodynamic responses to head-up tilt test (HUTT) in children and adolescents with unexplained sighing. One hundred ninety-two children and adolescents complaining of unexplained sighing were enrolled as study group after excluding chest wall, lung, heart diseases, and psychogenic disorders. Sixty-nine healthy individuals were enrolled as control group. All the subjects underwent HUTT. Nitroglycerin-stimulated HUTT positive rate was higher in the study group than the control group (24.0% vs 10.1%, P = 0.014). In total, 32.3% of patients with sighing had positive responses to HUTT, which was higher than that of healthy individuals (32.3% vs 15.9%, P = 0.009). Among 62 cases with positive responses to HUTT in the study group, 48 cases were vasoinhibitory type vasovagal syncope (VVS), 5 cases were mixed type VVS, 3 cases were cardioinhibitory type VVS, 5 cases were postural tachycardia syndrome, and one case was orthostatic hypertension. Sighing patients with positive responses to HUTT had female dominance (54.8% vs39.2%, P = 0.045), older mean age (9.6 ± 2.8 vs 8.1 ± 2.7years old, P = 0.001), higher basic systolic blood pressure (104.8 ± 10.4 vs 101.1 ± 9.9mmHg, P = 0.019), and higher diastolic blood pressure (66.0 ± 7.5 vs 62.9 ± 9.2mmHg, P = 0.021) compared with those of negative responses. CONCLUSIONS: Nearly one-third of children and adolescents with unexplained sighing had positive responses to HUTT, demonstrating that sighing was related to dysfunction of the autonomic nervous system. Elder female patients with higher systolic and diastolic blood pressure were more likely to have positive responses to HUTT.

The Repolarization Period during the Head-Up Tilt Test in Children with Vasovagal Syncope.

Background: Electrocardiography (ECG) and the head-up tilt test (HUTT) are vital in clinical work-up in children with vasovagal syncope (VVS). Ventricular repolarization parameters (QT) measured during the HUTT can be indicative of electrical instability; however, these parameters are not frequently assessed. This study aimed to investigate if ventricular repolarization parameters measured during the HUTT could be indicative of future ventricular arrhythmias in children with syncope. Methods: The shape and amplitude of the T-wave and parameters of the repolarization period (QT, QTpeak, Tpeak-Tend) were evaluated in a resting ECG performed on the first day of hospitalization and in ECGs performed during three phases of the HUTT. Results: In the after-tilt phase of the HUTT, 19/30 children displayed a change in T-wave morphology. QTc was significantly longer in VVS I compared to that in VVS II patients, but not in the controls (p = 0.092). Conclusions: We need further follow-up studies to establish the clinical importance of abnormal dynamics of the repolarization period in children with VVS and negative HUTT. Therefore, children with abnormal T-wave refraction and prolonged duration of the TpTe should remain under the care of a cardiological outpatient.

Autonomic Responses to Head-Up Tilt Test in Children with Autism Spectrum Disorders.

Autism Spectrum Disorders (ASD) is a group of neurodevelopmental disorders often manifested by social and behavioral deficiencies. Autonomic dysfunction is frequently reported in the autistic population but the mechanisms remain largely unknown. We aimed to characterize the cardiac autonomic profile of children with autism during a head-up tilt test. Thirty-nine male children were recruited: 19 controls (9.9±1.6years) and 20 children with ASD without intellectual disability (10.7±1.2years). Each child underwent a head-up tilt test on a motorized tilt table. After a 10min resting period in the supine position, subjects were tilted head-up to 70° on the table for 10min. Heart rate and blood pressure variabilities were continuously recorded using non-invasive Nexfin monitoring. The head-up tilt test significantly altered heart rate variability (p<0.001 for both groups) and greater parasympathetic responses were found in the ASD group compared to controls (p<0.05). In the supine position baroreflex sensitivity was higher in children with ASD than in the controls (p<0.05) and significantly decreased during the tilt test in the ASD group, but not in controls. Our results showed that children with ASD did not have clinical signs of dysautonomia in response to a head-up tilt test. However, in children with ASD higher parasympathetic responses with the same sympathetic modulations during orthostatic stress suggest parasympathetic dominance in this population.

Changes of plasma intermedin during head-up tilt test in children with postural tachycardia syndrome and its significance

To explore possible mechanisms of postural tachycardia syndrome (POTS) by comparing plasma intermedin (IMD) during head-up tilt test (HUTT) in children with POTS. The study subjects were divided into two groups: POTS group and control group. The POTS group consisted of twenty-nine children (male 14, female 15) with POTS, the mean age (12.4 ±3.1) years old, admitted into Peking University First Hospital from November 2013 to June 2014. The control group consisted of 32 healthy children (male 17, female 15). Their mean age was (11.6±2.2) years old, who were confirmed as healthy by physical examination and HUTT. Finapres Medical System was used to continuously monitor heart rate and blood pressure during HUTT, and electrocadiogram was performed. Supine systolic and diastolic blood pressure, mean arterial pressure (MAP), ΔMAP (standing mean arterial pressure-supine MAP), supine heart rate and ΔHR (standing HR-supine HR) were compared between POTS group and control group. Sandwich immunoluminescence assay was used to test plasma IMD. The plasma IMD level was compared in supine between POTS and control group. The plasma IMD level in supine was compared with HUTT in POTS group. No significant differences were found in age, height, weight, supine systolic and diastolic blood pressure, MAP, ΔMAP and supine heart rate between POTS group and control group (P>0.05). ΔHR in POTS group was significantly higher than that of control group ((48±10) vs. (22±7) beats /min, t=9.797, P<0.05). The plasma IMD level in POTS group was lower than that of control group in supine position ((497±61)×10(-6) vs. (529±58)×10(-6) mg/L, t=2.117, P<0.05). But, it was higher during HUTT than supine IMD in POTS group ((537±57) ×10(-6) vs. (497±61)×10(-6) mg/L, t=-2.464, P<0.05). The plasma delta IMD level (HUTT vs. supine) was positively correlated with delta HR in POTS group (r=0.435, P<0.05). The excessively high heart rate during HUTT have a positive correlation with plasma IMD, which may play a role in the pathogenesis of POTS in children.

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.

Diagnosis of unexplained syncope in children: a multi-center study

To examine the diagnostic value of head-up tilt test in children with unexplained syncope (UPS). A total of 379 children (171 males, 208 females) aged 3-18 years, mean age (12 +/- 3) years with unexplained syncope from Beijing, Hunan, Hubei and Shanghai and undergoing baseline head-up tilt tests (BHUTT) or head-up tilt tests potentiated with nitroglycerine (SNHUTT) under a quiet circumstance were selected as the syncope group. Ten healthy children (5 males, 5 females) aged 9-15 years with a mean age of (11.4 +/- 2.1) years, were recruited as the control group. SPSS 10.0 software was used for data analysis. In 379 children with unexplained syncope, 67 (17.7%) were of postural orthostatic tachycardia syndrome (POTS), 157 (41.4%) of vasovagal syncope vasoinhibitory pattern, 14 (3.7%) of vasovagal syncope cardioinhibitory pattern, 47 (12.4%) of vasovagal syncope mixed pattern, 1 (0.3%) of orthostatic hypotension (OH) and 93 children (24.5%) of UPS. In syncope group and control group, the positive rate of BHUTT was 55.9% and 0 respectively and it was 75.5% and 20.0% respectively for SNHUTT. During BHUTT, the mean time of positive response occurrence was (16 +/- 12) minutes, and the posture when positive response appeared was at a tilt angle of 60 degrees. For SNHUTT, the mean time of positive response occurrence was (6 +/- 4) minutes and the posture was at a tilt angle of 60 degrees when potentiated with nitroglycerine. HUTT is an objective diagnostic tool of UPS. With a high diagnostic positive rate, SNHUTT can improve the diagnostic positive rate of BHUTT. Meanwhile the time of positive response occurrence during SNHUTT is markedly shorter than BHUTT.

Tilt testing potentiated with sublingual nitroglycerin in children with unexplained syncope

The aim of this prospective study was to assess the diagnostic value of a sublingual nitroglycerin (NTG) potentiated head-up tilt (HUT) testing protocol in children with unexplained syncope. One hundred and sixty-four consecutive paediatric patients with syncope of unknown origin and no evidence of organic heart disease (115 female, mean age 13 +/- 3 years) and 29 control children underwent a sublingual NTG-potentiated tilt testing protocol. Paediatric patients and controls were tilted at 60 degrees for 20 min and, if no symptom occurred, for other 15 min after sublingual 400 mug spray NTG administration. During the drug-free phase of the test, 13 patients (8%) and no controls had a positive response. After drug administration, a positive response occurred in another 88 patients (55%) and in four controls (14%), whereas an exaggerated response was observed in nine patients (5%) and in four controls (14%). Thus, the positive rate and specificity of sublingual NTG HUT test in children were 63 and 86%, respectively. No relevant adverse events were observed during the test. Tilt testing potentiated with sublingual NTG has proved to be effective and safe in unmasking the neurally mediated origin of unexplained syncope in children. The NTG challenge greatly increased the positive rate of passive tilt, with a small decrease in specificity.

Provocation of Neurocardiogenic Syncope During Head-up Tilt Testing in Children: Comparison Between Isoproterenol and Nitroglycerin

Although nitroglycerin- and isoproterenol-augmented tilt tests are of equal value in the diagnosis of neurocardiogenic syncope in adults, no data exist in children. We compared the sensitivity and specificity of the 2 tests in a pediatric population. We studied 85 patients (33 boys; mean age: 11.6 +/- 2.9 years). Of them, 56 had a diagnostic history of neurocardiogenic syncope, whereas 29 served as controls. After a negative passive phase, they were randomly assigned to either intravenous isoproterenol or sublingual nitroglycerin, and tilt was continued for 20 minutes. Sensitivity was 0.78 for the isoproterenol test and 0.79 for the nitroglycerin test, but specificity was significantly higher for isoproterenol test compared with nitroglycerin test. In patients with a positive test, the duration of the recovery period was significantly longer after nitroglycerin (8.4 +/- 2.7 minutes) than after isoproterenol (5.1 +/- 1.6 minutes). Nitroglycerin- and isoproterenol-augmented tilt tests are associated with equal sensitivity in the diagnosis of neurocardiogenic syncope in children and adolescents. However, nitroglycerin results in more false-positive tests and produces more prolonged vasovagal symptoms. Our data do not support the routine use of nitroglycerin in the evaluation of syncope in this age group.

Common patterns of response to the head-up tilt test in children and adolescents

Testing using the head-up tilt table is performed regularly as a diagnostic tool in the evaluation of syncope. Recommendations for protocols, and interpretation of the results, however, are mainly based on experience in adults. We evaluated the results of tilt table testing in 100 consecutive children and adolescents aged from 6 to 18 years and referred for investigation of syncope. Over half the patients, 55%, proved impossible to classify using the criterions established by the European Society of Cardiology. Based on our data, we propose a modified classification for responses to tilt table testing in the young.

Association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope

To explore the different hemodynamic patterns during the course of head-up tilt tests in children with unexplained syncope and the association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope. 100 pediatric patients with unexplained syncope, aged 11 +/- 2 (6-16), 36 male and 64 female, with the mean course of 10 +/- 16 months (2 d-5 y), underwent head-up tilt tests or head-up tilt tests potentiated with nitroglycerine under quiet circumstance. Blood pressure and heart rate were monitored simultaneously. According to their different hemodynamic patterns, they were divided into vasovagal response pattern, postural orthostatic tachycardia syndrome (POTS) response pattern, orthostatic hypotension (OH) response pattern and normal response pattern. The vasovagal response was divided into vasodepressor, cardioinhibitory and mixed patterns. The distribution and different clinical features of different response patterns in the unexplained syncope were also studied. Fifty (50%) of the 100 children with unexplained syncope displayed the hemodynamic pattern of vasovagal response, among which 31 (31%) displayed the pattern of vasodepressor response, 7 (7%) cardioinhibitory response, and 12 (12%) mixed response. Thirty-three patients (33%) displayed POTS response, 2 (2%) OH response, and 15 (15%) the normal hemodynamic response. Patterns of dysautonomic response and chronotropic incompetence were not observed in these children with unexplained syncope. The age of the children with normal response during HUT was 10 +/- 3 years, significantly younger than that of the children with vasovagal response and POTS response (12 +/- 2 and 12 +/- 2, both P < 0.01). There were no differences in sex ratio and duration of syncope among the vasovagal response, POTS and normal response. But the syncopal spells in the children with POTS response was less frequent and the baseline heart rate of the children with POTS response was 81 +/- 7, significantly faster than that of the children with vasovagal response and normal response (71 +/- 9 and 74 +/- 7, both P < 0.01). There was no significant difference in the baseline blood pressure among the children with vasovagal response, POTS and normal response. There were also no significant differences in the age, sex ratio, and duration of syncope, number of syncopal spells, baseline heart rate, and baseline blood pressure among the children with vasodepressor response, cardioinhibitory response and mixed response. There are different hemodynamic response patterns in head-up tilt testing in children with unexplained syncope, and there was some association between hemodynamic response patterns and their clinical features.

Reproducibility of the head-up tilt test results in children with vasovagal syncope

Background: This prospective study aims to investigate the reproducibility of HUTT results in children with typical history of vasovagal syncope. Methods: Between October 1996 and October 1999, 58 children with a history of typical vasovagal syncope attacks were evaluated with head up tilt test (HUTT). The table was tilted to 60° and the patients were monitored for heart rate and blood pressure changes during 45 min. No provocative agents were used. The test was repeated a week later at a similar setting. Results: Of 58 patients, 39 had positive and 19 had negative response during the initial test. During the second test, the positive response was reproduced in 29 cases (50%), and the negative response was reproduced in 16 cases (28%). Ten patients (17%) with an initial positive test had a negative second test. A negative test became positive only in three patients (5%). There were 12 vasodepressor, four cardioinhibitor and 23 mixed responses among the initial tests. Only in four patients did the type of the response change from vasodepressor to a mixed type during the second test. The reproducibility of a positive tilt test was 74.4% (29/39), the negative tilt test was 84.2% (16/19), and the overall reproducibility of the HUTT was 77.6% (45/58). Conclusions: Unprovoked HUTT in children is reproducible when repeated on different days and similar settings and the results are comparable to the ones with adult patients.