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.

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.

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.

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 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.

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

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.

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.

Obgective To observe the effect of hydrogen sulfide (H2S) on vasorelaxation and expression of guanosine 3',5'-cyclic phosphate (cGMP) and activity of cyclic nucleotide phosphodiesterase (PDE) in vascular tissue.Methods H2S donor was provided by sodium bisulfide sodium hydrosulfide.The isolated perfused rat thoracic aorta rings were used to test the relaxation responses to H2S,which recorded by Power Lab system,and the enzyme linked immuno assay was used to detect intracellular cGMP.The activity of PDE was evaluated by using cyclic nucleotide PDE assay kit.Results (1) H2S relaxed the thoracic aorta rings,and the half maximal effective concentration (EC50) for the H2 S relaxation curve,represented by the corresponding concentration of H2 S that achieved 50％ of the maximum relaxation effect,was (1.79 ± 0.31) × 10-5 mol/L.(2)The cGMP content in vascular tissue increased from (22.29 ± 1.59) pmol/L to(41.45 ± 7.49) pmol/L and (31.35 ± 2.56) pmol/L after incubation with 50 μmol/L and 300 μmol/L H2 S,respectively (t =-3.09,t =-2.88;all P ＜ 0.05,n =7-8).(3) cGMP could be lysed into 5'-guanylicacid(5'-GMP) by PDE,which was an important pathway for cGMP degradation.This study showed that PDE activity was decreased in vascular tissue,the 5'-GMP decreased from (0.52 ±0.06) mol/L to (0.25 ±0.06) mol/Land (0.27 ±0.07) mol/L after incubation with 50 μmol/L and 300 μ mol/L H2S,respectively (t =3.21,t =2.58;all P ＜ 0.05,n =7-8).Conclusion The vasorelaxant effects of H2 S might be related to the inhibited activity of PDE and elevated content of cGMP.

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.