Syncope is a common emergency in children and adolescents, which has serious influence on the quality of life.After nearly 30 years′ exploration, great progress has been made in the diagnosis and treatment of children′s syncope in China.We have established the diagnosis procedure of syncope in line with health economics.We have also proposed the concept of individualized precise treatment of syncope in children for the first time.The disease spectrum of syncope in children has been continuously enriched.Relevant progresses have been cited by the guidelines of the United States, Europe and Canada, which has also been unanimously recognized by international experts.

Objective:To investigate the regulatory effects of endogenous nitric oxide (NO) on the activity of superoxide dismutase-1 (SOD1) and apoptosis of human umbilical vein endothelial cells (HUVECs).Methods:HUVECs were taken as the research object.The endothelial NO synthase (eNOS) short hairpin RNA(shRNA) lentivirus was employed to transfect HUVECs to knock down eNOS.HUVECs were divided in 4 groups: the scramble group, the eNOS shRNA group, the eNOS shRNA + sodium nitroprusside(SNP) group and the eNOS shRNA+ SNP+ tris (2-carboxyethyl) phosphine hydrochloride (TCEP) group.The protein expressions of eNOS and SOD1 dimer/monomer in cells were detected by western blot.The activity of SOD was detected by the enzyme-linked immunosorbent assay.The NO content in cells was detected with NO fluorescence probe.The level of superoxide anion in HUVECs was detected with dihydropyridine (DHE). The terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay was adopted to detect the apoptosis of HUVECs in situ.Results:Compared with the scramble group, the endogenous NO content (2.690±0.420 vs.15.029±2.193, P<0.01), eNOS protein expression (1.000±0.778 vs.3.141±0.199, P<0.01), SOD1 dimer/monomer ratio (4.6±1.0 vs.7.6±2.0, P<0.05) and SOD activity [(0.432±0.254) Carmen′s unit/10 4 cell vs.(1.000±0.116) Carmen′s unit/10 4 cell, P<0.01] were significantly decreased, while the level of intracellular superoxide anion (11.180±1.560 vs.6.146±1.007, P<0.01) and HUVECs apoptosis [75.0 (55.0, 100.0)% vs.0 (0, 0)%, P<0.01] were significantly increased in the eNOS shRNA group.Compared with the eNOS shRNA group, the content of endogenous NO (16.705±0.116 vs.2.690±0.420, P<0.01), the ratio of SOD1 dimer/monomer (7.3±2.0 vs.4.6±1.0, P<0.05) and the activity of SOD [(0.737±0.060) Carmen′s unit/10 4 cell vs.(0.432±0.254) Carmen′s unit/10 4 cell, P<0.05] were significantly increased, while the level of superoxide anion (6.897±1.648 vs.11.180±1.560, P<0.01) and the HUVECs apoptosis [0 (0, 0)% vs.75.0 (55.0, 100.0)%, P<0.01] were significantly decreased in the eNOS shRNA+ SNP group.Compared with the eNOS shRNA + SNP group, the ratio of SOD1 dimer/monomer (4.4±0.9 vs.7.3±2.0, P<0.05) and the activity of SOD [(0.214±0.084) Carmen′s unit/10 4 cell vs.(0.737±0.060) Carmen′s unit/10 4 cell, P<0.01] were significantly decreased, while the level of superoxide anion (10.917±1.552 vs.6.897±1.640, P<0.01) and the apoptosis level of HUVECs[63.6 (55.0, 90.0)% vs.0 (0, 0)%, P<0.01] were significantly increased in the eNOS shRNA+ SNP+ TCEP group.However, there was no significant difference in the NO content (16.112±0.926 vs.16.705±0.116, P>0.05). Conclusions:Endogenous NO could effectively antagonize the apoptosis of endothelial cells by increasing the cysteine-dependent SOD1 dimer/monomer ratio, enhancing SOD activity and inhibiting the accumulation of reactive oxygen species.

Objective:To explore the significance of plasma homocysteine (Hcy) as a new biomarker for the differential diagnosis of postural tachycardia syndrome (POTS) and suspected myocarditis in children.Methods:A total of 24 children diagnosed with POTS and 21 children diagnosed with suspected myocarditis treated in the Pediatrics Department of the Peking University First Hospital from July to December 2016 were included in the study.Plasma Hcy levels were measured in each subject and compared between children with POTS and suspected myocarditis.The receiver operating characteristic (ROC) curves were depicted for assessing the diagnostic potential of Hcy in distinguishing POTS from suspected myocarditis.Results:Plasma Hcy level in the POTS group was significantly higher than that in the suspected myocarditis group [(14.25±8.09) μmol/L vs.(8.99±3.19) μmol/L], which was also significantly higher than that of the mean levels in Beijing children [(8.82±5.58) μmol/L] (all P<0.05). When the cut-off was 9.36 μmol/L, the area under the ROC curve was 0.76, and the sensitivity and specificity for distinguishing POTS from suspected myocarditis were 71% and 68%, respectively. Conclusions:Plasma Hcy levels are helpful in the differential diagnosis of POTS and suspected myocarditis in children.

Vasovagal syncope (VVS) and postural tachycardia syndrome (POTS) are the main forms of orthostatic intolerance in pediatrics and both are underlying causes of neurally-mediated syncope. In recent years, increasing attention has been paid to the management of VVS and POTS in children and adolescents. A number of potential mechanisms are involved in their pathophysiology, but the leading cause of symptoms varies among patients. A few studies thus have focused on the individualized treatment of VVS or POTS based on selected hemodynamic parameters or biomarkers that can predict the therapeutic effect of certain therapies and improve their effectiveness. This review summarizes the latest developments in individualized treatment of VVS and POTS in children and indicates directions for further research in this field.

Kawasaki disease (KD) is an acute, self-limiting, and medium-sized vasculitis, which has been the commonest cause of acquired heart disease in children in developed countries.Without timely diagnosis and treatment, up-to 25% of the affected children may develop coronary artery abnormalities (CAA). Due to the lack of the specific diagnostic method, KD is mainly diagnosed according to the clinical criteria.As a result, typical KD is recognized easily, but it is a big challenge to diagnose KD patients with incomplete or atypical symptoms.The pandemic of novel coronavirus disease 2019 (COVID-19) around the world makes the diagnosis of KD even more complex.In this review, hot issues in diagnosing KD were discussed according to the 2017 guidelines for diagnosis and treatment of KD recently published by the American Heart Association (AHA), expecting to provide help for diagnosis of KD children.

Blood Coagulation Disorders ; physiopathology ; Blood Pressure ; physiology ; Hemodynamics ; physiology ; Humans ; Orthostatic Intolerance ; physiopathology ; Platelet Count ; Posture ; physiology

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