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ABSTRACT: AIM: This study was designed to evaluate the diagnostic value of B-type natriuretic peptide (BNP) in syncope in children and adolescents. METHODS: Serum BNP concentration was measured by electrochemiluminescence assay in 62 consecutive children and adolescents hospitalized for syncope. RESULTS: Of the 62 children and adolescents hospitalized for syncope, 39 had non-cardiac syncope, 37 (59.7%) of whom had autonomic-mediated reflex syncope, and two (3.2%) had syncope of unknown cause. Twenty-three patients (37.1%) had cardiac syncope; 11 of these had cardiac arrhythmias and 12 had structural cardiac/cardiopulmonary disease. Patients with cardiac syncope had significantly higher serum BNP than those with non-cardiac syncope (958.78 ± 2443.41 pg/ml vs. 31.05 ± 22.64 pg/ml, p < 0.05). Logistic multivariate regression analysis revealed that urinary incontinence during syncopal episodes, ECG abnormalities and increased serum BNP levels were independent predictors for cardiac syncope. At a cut-off value of 40.65 pg/ml, serum BNP was associated with significant risk for a cardiac cause of syncope, with sensitivity 73.9% and specificity 70.0% for distinguishing cardiac syncope from non-cardiac syncope. CONCLUSION: Serum BNP was helpful in differentiating cardiac syncope from non-cardiac syncope in children and adolescents ©2013 The Author(s)/Acta Paediatrica ©2013 Foundation Acta Paediatrica.
Acta Paediatrica 02/2013; · 2.07 Impact Factor
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ABSTRACT: The present study was designed to analyse the usefulness of a modified Calgary score system during differential diagnosis between cardiac syncope and postural orthostatic tachycardia syndrome-associated syncope through a large sample sized clinical investigation. The study included 213 children, including 101 boys and 112 girls, with cardiac syncope or postural orthostatic tachycardia syndrome-associated syncope in the age group of 2-19 years (mean 11.8 ± 2.9 years). A modified Calgary score was created, which was analysed to predict differential diagnoses between cardiac syncope and postural orthostatic tachycardia syndrome-associated syncope using a receiver operating characteristic curve. The median of modified Calgary scores for cardiac syncope was -5.0, which significantly differed from that of postural orthostatic tachycardia syndrome (0.0; p < 0.01). The sensitivity and specificity of a differentiation score of less than -2.5 was 96.3% and 72.7%, respectively. Owing to the fact that the modified Calgary score was an integer, when less than -3.0 the diagnosis could be considered as cardiac syncope. The modified Calgary score could be used to make an initial differential diagnosis between cardiac syncope and postural orthostatic tachycardia syndrome-associated syncope in the clinic.
Cardiology in the Young 10/2012; · 0.76 Impact Factor
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ABSTRACT: Pulmonary hypertension (PH) is a clinical hemodynamic syndrome characterized by increased pulmonary artery pressure and pulmonary vascular resistance. It can cause right ventricular failure, and even death. Pediatric PH is not very common, but is a greatly hazardous disease that leads to a high mortality rate. Therefore, many registry organizations have been established in the world to strengthen the study of diagnosis and treatment of the disease, and improve the understanding of pediatric PH. This article reviewed recently published researches, as well as presented a comprehensive understanding of PH, including definition, classification, epidemiology, prognosis and treatment.
Korean Circulation Journal 08/2012; 42(8):513-8.
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ABSTRACT: AimThis study was designed to investigate the value of history taking in identifying children with cardiac syncope, and to improve diagnostic efficiency and accuracy in children with cardiac syncope.Methods and ResultsWe compared the characteristics of a group of children and adolescents with cardiac syncope at the Pediatric Syncope Unit of five hospitals in China with those with typical vasovagal syncope. We included a cohort of 275 patients in Pediatric Syncope Unit. A cardiac cause of syncope was established in 31 patients, autonomic-mediated reflex syncope in 214, non-syncopal attacks in 15, and in the remaining 15 the cause of syncope remained unexplained. Cardiac syncope was triggered by exercise, whereas vasovagal syncope by prolonged standing, warm-crowded place, and fear or pain emotion. Syncopal spells occurred at various positions in cardiac syncope. Children who had prodromal symptoms with cardiac syncope were significantly fewer than those with vasovagal syncope. Most children with cardiac syncope had history of abnormal electrocardiogram findings when compared with children suffering from vasovagal syncope. On multivariable analysis, history of abnormal electrocardiogram findings and exercise-triggered syncope were independent predictors of cardiac syncope.ConclusionChildren and adolescents with a history of abnormal electrocardiogram findings and exercise-related syncope spells were at high risk for cardiac syncope.
Cardiology in the Young 03/2012; · 0.76 Impact Factor
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ABSTRACT: To investigate whether 24-hour urinary sodium excretion could be an indicator of the effectiveness of salt supplementation in children with postural orthostatic tachycardia syndrome (POTS).
The patient group comprised 30 children with POTS, and the control group comprised 10 healthy children. Serum sodium and 24-hour urinary sodium excretion were measured in all children, and the relationship between 24-hour urinary sodium and symptom severity was analyzed in the 30 patients. At 1 month after initiation of salt supplementation, the receiver operating characteristic curve was used to explore the probability of correctly discriminating responders to salt supplementation from nonresponders using 24-hour urinary sodium excretion as an indicator.
Patients with POTS had lower 24-hour urinary sodium excretion than controls (P = .022). Symptom severity was negatively correlated with 24-hour urinary sodium excretion (OR, -0.754; P = .000). The receiver operating characteristic curve demonstrated a sensitivity of 76.9% and specificity of 93% for correct prediction of responders and nonresponders to salt supplementation when a 24-hour urinary sodium excretion of 124 mmol/24 hours was used as the cutoff value.
Our results indicate that 24-hour sodium excretion of <124 mmol/24 hours is an indicator of the effectiveness of salt supplementation in children and adolescents with POTS.
The Journal of pediatrics 03/2012; 161(2):281-4. · 4.02 Impact Factor
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ABSTRACT: The implications of autophagy-related genes in serious neural degenerative diseases have been well documented. However, the functions and regulation of the family genes in embryonic development remain to be rigorously studied. Here, we report on for the first time the important role of atg5 gene in zebrafish neurogenesis and organogenesis as evidenced by the spatiotemporal expression pattern and functional analysis. Using morpholino oligo knockdown and mRNA overexpression, we demonstrated that zebrafish atg5 is required for normal morphogenesis of brain regionalization and body plan as well as for expression regulation of neural gene markers: gli1, huC, nkx2.2, pink1, β-synuclein, xb51 and zic1. We further demonstrated that ATG5 protein is involved in autophagy by LC3-II/LC3I ratio and rapamycin-induction experiments, and that ATG5 is capable of regulating expression of itself gene in the manner of a feedback inhibition loop. In addition, we found that expression of another autophagy-related gene, atg12, is maintained at a higher constant level like a housekeeping gene. This indicates that the formation of the ATG12–ATG5 conjugate may be dependent on ATG5 protein generation and its splicing, rather than on ATG12 protein in zebrafish. Importantly, in the present study, we provide a mechanistic insight into the regulation and functional roles of atg5 in development of zebrafish nervous system.
Autophagy 12/2011; 7(12):1514-27. · 7.45 Impact Factor
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ABSTRACT: The study was designed to explore flow-mediated vasodilation (FMD) and endothelium function in children with postural orthostatic tachycardia syndrome (POTS). The patient group consisted of 46 children 12 +/- 3 years of age who were diagnosed with POTS from June 2008 to January 2009 by head-up test or head-up tilt test at Peking University First Hospital. Twenty healthy children 12 +/- 4 years of age were selected for the control group. Plasma concentrations of nitric oxide (NO) and activity of NO synthase (NOS) were determined in the patient and control groups. FMD of each participant's brachial artery was measured using color Doppler vascular ultrasound and a comparison of FMDs and plasma NO and NOS activities between the 2 groups was done using independent t test. No significant differences were found between the POTS and control groups in age, sex ratio, height, body weight, baseline blood pressure, heart rate, and baseline brachial artery diameter. Patients in the POTS group had larger FMD (10.8 +/- 4.4%) than children in the control group (5.7 +/- 2.2%), and this difference was significant (p <0.01). Plasma NO and NOS levels were significantly higher in the POTS group than in the control group (NO 74 +/- 19 micromol/L in POTS group vs 62 +/- 6 micromol/L in control group, p <0.01; NOS 21 +/- 3 U/mL in POTS group vs 15 +/- 1 U/mL in control group, p <0.01). In addition, there was a significant correlation between FMD and the NOS activity. In conclusion, augmented FMD and abnormal function of vascular endothelium may play an important role in POTS in children.
The American journal of cardiology 08/2010; 106(3):378-82. · 3.58 Impact Factor
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Acta Paediatrica 03/2010; 99(5):641 - 641. · 2.07 Impact Factor
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ABSTRACT: The appropriate diagnostic protocol for children with syncope has not been well established. A diagnostic protocol was developed and prospectively implemented to improve the diagnostic performance of paediatricians.
The study population included 474 consecutive patients (range 6-17 years) presenting with a syncopal spell in one of the five participating hospitals of China. In step 1, all patients underwent initial evaluation for history, physical examination, standing test and standard electrocardiography (ECG). In step 2, priority was given to cardiographic tests for possibly cardiogenic syncope, or electroencephalographic examination and brain imaging for suspected neurological syncope, or psychiatric tests for suspected psychiatric syncope. Patients with unexplained syncope underwent head-up tilt testing (HUT).
The initial evaluation gave a definite diagnosis in 59 (12.4%) and possible diagnosis in 54 of the 474 patients. Further testing gave a definite diagnosis for 326 patients (69.7%). After the entire diagnostic protocol, definite diagnosis was established in 385 patients (81.1%). Autonomic-mediated reflex syncope (AMS) accounted for 73.0% of cases. The average cost of diagnostic results per patient was RMB 1030.24 +/- 150.09 ($118.42 +/- 17.25).
The use of a simplified diagnostic protocol for children and adolescents with syncope improves diagnostic yield.
Acta Paediatrica 02/2009; 98(5):879-84. · 2.07 Impact Factor
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ABSTRACT: Previous studies that have assessed the effects of beta blockers on preventing vasovagal syncope provide conflicting results. We sought to evaluate the effectiveness of metoprolol versus conventional treatment in preventing the recurrence of syncope in children and adolescents.
Twenty-eight children and adolescents (8 boys, 20 girls; mean age, 12+/-3 years; age range, 8-17 years) with vasovagal syncope were randomized to receive either metoprolol (metoprolol group; dosage range, 0.5-1.5 mg/kg/d) or conventional treatment (control group) for 1 year. The main outcome measure was the first recurrence of syncope beginning 2 weeks after the start of treatment. The mean follow-up was 22+/-10 months. Time to first recurrence of syncope was analyzed using Kaplan-Meier curves and compared with a log-rank test.
The 2 groups did not differ in terms of clinical characteristics. The number of syncopal episodes before tilt testing was 8+/-6 in patients in the metoprolol group and 9+/-6 in patients in the control group (P=0.150). Syncope recurred in 6 of 14 children in the metoprolol group and in 4 of 14 children in the control group. No significant between-group differences were found regarding the probability of freedom from a recurrent episode of syncope during follow-up (metoprolol vs controls, 43% vs 29%; P=0.389), as demonstrated by Kaplan-Meier curve analyses.
Recurrence of vasovagal syncope in children and adolescents treated with metoprolol is similar to that of patients treated with conventional therapy.
Medical science monitor: international medical journal of experimental and clinical research 05/2008; 14(4):CR199-203. · 1.70 Impact Factor
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ABSTRACT: This study aimed to improve diagnostic efficacy of syncope in children by analyzing the aetiology and clinical characteristics of syncope in Chinese children.
We retrospectively analyzed the causes of syncope and diagnostic workup in 154 consecutive children seen in the Department of Pediatrics, Peking University First Hospital, China, because of a syncope-related event.
In all patients with transient loss of consciousness (TLOC), there were 136 (88.31%) patients attributing to syncope, and 18 (11.69%) belonging to nonsyncopal cases. Neurally mediated syncope (NMS) was the most common cause of syncope (99 cases; 64.3%), with cardiac causes ranking second (10 cases; 6.5%). Other nonsyncopal causes included psychiatric problems and neurological and metabolic disorders. In 25 cases (16.2%), the cause was uncertain. Cases of NMS often had clear inducement of syncope and prodromes. Children with cardiac syncope often had a history of cardiac disease, were often younger than those with NMS, and showed exercise-related syncope, syncope spells in any body position or at an early age, or sudden death in family members but no prodromes. Neurological disorder was suspected in cases of TLOC with seizures, TLOC spells in any position, postictal phase of disorientation or abnormal neurological signs. A metabolic cause is suspected with a history of metabolic disease, prolonged anger, or violent vomiting and diarrhoea. Children with psychiatric disorders were adolescent girls, with prolonged TLOC spells, who had more frequent TLOC. Although many tests were used in diagnosis, most were not goal directed. Now, electrocardiography is recommended in almost all children with syncope. Neurological testing, including electroencephalography and computed tomography were rarely helpful unless with evidence of neurological signs and symptoms. Head-up tilt test (HUTT) was most useful in children with recurrent syncope in whom heart disease was not suspected.
NMS was the most common cause of syncope. We recommended HUTT as the important basis of the TLOC workup.
Acta Paediatrica 11/2007; 96(10):1505-10. · 2.07 Impact Factor
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ABSTRACT: This paper summarizes the personality and generality of common used topologies in power supply and puts forward novel switching-off model by analyzing and comparing the experiment waveforms with theoretical model. In the model, the effects of equivalent parallel capacitor of D-S and leakage inductance in the circuit serried with MOSFET drain are taken into account. The calculated results are compared with those of tested. The proposed switching model process and derived algorithm appears available for most of MOSFET
Industrial Electronics Society, 2005. IECON 2005. 31st Annual Conference of IEEE; 12/2005
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ABSTRACT: Generally, the reverse recovery issue of diode is difficult to deal with, which causes large added loss and EMI. Different down slopes for diode reverse voltage mean different working conditions, and this paper shows you the general concept with different down slopes and how to predict the reverse recovery current to calculate the relative switching loss. The empirical equations are deduced based on physical concepts and verified by lab measurements.
Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual; 02/2004
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ABSTRACT: This paper presents the analysis, design and optimization of a
novel DC/DC power converter-the boost half bridge (BHB) converter for
battery input applications. All switching of the BHB converter is
carried out under ZVS conditions. An experimental prototype of 40~75V
input, 400V/2kW output has a total efficiency of 94.5%. Theoretical
analyses of the power converter, along with experimental results, are
provided
Applied Power Electronics Conference and Exposition, 2002. APEC 2002. Seventeenth Annual IEEE; 02/2002
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ABSTRACT: This paper presents a novel DC/DC converter-Taping Transformer Boost Half Bridge (TTBHB). In this converter, all switches are working under ZVS mode, thus switching losses are small and the duty cycle range of TTBHB is larger than 50%, this reduces conduction losses and results in wide input range. The EMI filter of TTBHB is very small, for the CCM input. A synchronous rectifier can be easily self-driven by the transformer. Magnetic components can also be optimized according to the desired working duty cycle range. Theoretical analysis and simulation of the converter is provided.
Power Electronics Specialists Conference, 2002. pesc 02. 2002 IEEE 33rd Annual; 02/2002
