Syncope is one of the most common emergencies in the pediatric population.Autonomic -mediated reflex syncope,including postural tachycardia syndrome and vasovagal syncope,is the main cause.Although the clinical manifestations are similar,each subtype has its optimal treatment option.With the development of translational medicine in recent years,as well as the emergence of biomarkers,precision medicine has become possible,and will be the main direction in the future researches.

Arrhythmia-induced cardiomyopathy (AIC) is a myocardial disease condition in which left ventricular dysfunction and cardiomegaly are induced or mediated by atrial or ventricular arrhythmias.The pathophysiological mechanisms remain unclear.Early recognition of AIC and provision of prompt treatment with pharmacological or ablative techniques could result in symptom resolution and recovery of ventricular function.But,the long-term prognosis of these patients is not clear and needs further observation and research.

OBJECTIVE:To study the therapeutic effect of L-arginine on collagen metabolism of pulmonary artery in rats with high pulmonary blood flow METHODS:The rat model of pulmonary hypertension was established with an abdominal aorta and inferior vena cava shunting L-arginine was intragastrically given to the rats with shunt in L-arginine group(1g/(kg?d)) for 11 weeks After 11 weeks of experiment,the expressions of collagen Ⅰ and collagen Ⅲ in pulmonary artery were detected by immunohistochemical assay RESULTS:The expressions of collagen Ⅰ and collagen Ⅲ in shunt group elevated obviously compared with those in control group(P

Myocarditis is one of the most common acquired heart diseases in children,and one of the most common causes of a pediatric dilated cardiomyopathy phenotype.The myocarditis is a difficult issue in the diagnosis and the optimal means of therapy.A recent Pediatric Cardiomyopathy Registry (PCMR) analysis in the largest group of pediatric myocarditis patients ever studied confirmed that the most common outcome in pediatric myocarditis was cardiac recovery,but approximately 30％ of pediatric myocarditis patients would die or undergo heart transplantation.Animal studies and adult experience suggested that autoimmunity might contribute to cardiac dysfunction in myocarditis.Immunosuppressive and immunomodulating therapy for pediatric myocarditis remains controversial.Small case series have shown benefit of these therapies in pediatric myocarditis.A limited number of biomarkers associated both good (recovery) and poor (death or transplantation) outcomes could be identified.We should do our best to find these biomarkers in the future.

Syncope is a common clinical problem in children and adolescents. It is a major challenge for practicing physicians, and medical resource utilization and expenses associated with syncope management are enormous. A diagnostic protocol to syncope must be developed for children and adolescents for convenient and effective final diagnosis, and an analysis of cost-effectiveness is meaningful. Thus, according to the studies of syncope in children in China,the Chinese Pediatric Cardiology Society proposed the guidelines for diagnosis of syncope in children in China, and developed a simplified diagnostic protocol for children and adolescents with syncope. According to a multi-center prospective study,the diagnostic protocol in children and adolescents with syncope results in an improvement of diagnostic yield.

Hypertension in children and adolescents is defined as systolic blood pressure(SBP)and/ or dias-tolic blood pressure(DBP)≥95th percentile for age,gender and height,on at least 3 occasions. Primary hypertension is more common among children of older age or adolescents,while secondary hypertension accounts for more cases for younger children. Among causes of secondary hypertension,renovascular diseases,renal parenchymal diseases,cardio-vascular diseases,and endocrine diseases are common. An initial evaluation can be reached after history taking and physical examination,to decide whether it should be primary or secondary hypertension. Laboratory tests and procedures can further confirm the classification and etiology. There is an increase in prevalence of hypertension in children and adolescents,and an in - time diagnosis and evaluation of hypertension is important to help patients receive a better management of their conditions.

Sulfur dioxide (SO_2) is an ordinary air pollutant globally and harm to human health. L-cysteine is the major sulfur-containing amino acid and its normal metabolism can produce hydrogen sulfur (H_2S) and SO_2. It is realized that H_2S has various bioactivities and is the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO). Recently, attention has been paid to the physiologic effects of endogenous SO_2 and its derivatives (bisulfite and sulfite) in vivo, and recognized that SO_2 and its derivatives can lower blood pressure, change heart rates, participate in inflammatory reactions, and so on, suggesting that endogenous SO_2 may modulate the physiologic functions in vivo as a bioactive molecule.

Objective To evaluate the efficacy of β-blockers in treatment of postural orthostatic tachycardia syndrome( POTS) in children. Methods Clinical controlled trials were collected from a variety of medical electronic databases including PubMed(1990-2014),Excerpta Medica database(EMBASE 1990-2014),ELSEVIER(1990-2014),China National Knowledge Internet(CNKI 1990—2014) and WANFANG(1990—2014) by 2 researchers simultaneously and respectively based on same inclusion and exclusion criteria. Studies were assessed based on the Juni scale evaluation,and the Meta-analysis was conducted using the Rev-Man 5. 0 software. Results In total 8 clinical trials were included out of over 200 papers. Possible publication bias were assessed by Funnel plot analysis. Meta analy-sis of the 8 studies demonstrated that compared with the placebo group, metoprolol group showed significantly better ef-ficacy in treating children with POTS(RR=0. 37,95%CI:0. 21-0. 64,P=0. 000 5). Furthermore,these included trials were divided into different subgroups based on trial design ( randomized controlled trial/non-randomized con-trolled trial and Scored/N-scored) . Although no statistical heterogeneities were detected within each subgroups by the subgroup analysis,marked heterogeneities were found among subgroups; there was no significant difference of efficacy between metoprolol and placebos in treating POTS in non-randomized controlled trial group(RR=0. 68,95%CI:0. 45-1. 02,P=0. 06). Conclusions Low-dose metoprolol is effective in treating POTS,but the conclusion still needs to be tested by more large-scaled,multi-centered and standardized clinical randomized controlled trials.

Postural tachycardia syndrome (POTS) is one type of orthostatic intolerance.The treatment for POTS including non-drug treatment and medications,such as α-receptor agonists,β-recepter blockers and oral rehydration salts.The prognostic meaning of biomarkers and hemodynamic parameters in the POTS children treated with midodrine hydrochloride are discussed in this paper.

Objective To observe the regulatory effect and significance of hydrogen sulfide (H2 S)on low -density lipoprotein receptor (LDLR).Methods Mouse primary hepatocytes were divided into control group,low -den-sity lipoprotein (LDL)group and LDL +sodium hydrosulfide (NaHS,the donor of H2 S)group.The cells in LDL group were treated with LDL (50 mg/L)and the cells in LDL +NaHS group were pretreated with NaHS (100 μmol/L)for 0.5 hours and then treated with LDL (50 mg/L).Real -time PCR and Western blot were used to detect the expres-sions of LDLR mRNA and protein,respectively.Mouse primary hepatocytes were divided into control group,1,1′-dioctadecyl -3,3,3′,3′-tetramethyl -indocarbocyanine perchlorate low -density lipoprotein (DiI -LDL)group and DiI -LDL +NaHS group.The cells in DiI -LDL group were incubated with DiI -LDL (10 mg/L)for 3 hours.The cells in DiI -LDL +NaHS group were pretreated with NaHS (100 μmol/L)for 1 hour before DiI -LDL (10 mg/L) was added.Confocal method was used to measure the uptake of DiI -LDL by mouse primary hepatocytes,and fluores-cent quantitative method was performed to detect the content of DiI -LDL in the supernatant of mouse primary hepato-cytes.Results The levels of LDLR mRNA and protein in the mouse primary hepatocytes were significantly downregu-lated compared with those in the control group (t =5.733,P <0.01;t =2.527,P <0.05);after NaHS was adminis-tered,LDLR mRNA and protein level in the mouse primary hepatocytes were significantly upregulated (t =-7.639, P <0.01;t =2.388,P <0.05).In the mouse primary hepatocytes,compared with that in the control group,the uptake of DiI -LDL by cells in DiI -LDL group was increased;the uptake of DiI -LDL by mouse primary hepatocytes in DiI -LDL +NaHS group was significantly increased in comparison with that in the DiI -LDL group.Compared with that in the control group,the DiI -LDL content of culture supernatant in the DiI -LDL group was significantly increased (t =-39.156,P <0.01);after treatment with H2 S donor,the content of DiI -LDL in the culture supernatant was sig-nificantly decreased in comparison with that in the mouse primary hepatocytes without H2 S donor treatment (t =17.202,P <0.01).Conclusion H2 S upregulated the expression of LDLR protein in the mouse primary hepatocytes.