Hypertrophic cardiomyopathy (HCM) is one of the most important causes of sudden cardiac death in children and adolescents. Since the publication of the first Chinese consensus on pediatric HCM diagnosis in 2019, new and significant advances have been made in the diagnosis and management of HCM. To address these developments, the Cardiovascular Subspecialty Group of the Pediatrics Branch, Chinese Medical Association, in collaboration with the Precision Diagnosis and Treatment Collaborative Group for Childhood Cardiomyopathy, the Heart Failure Collaborative Group, the Genetic and Metabolic Cardiomyopathy Collaborative Group, and the Editorial Board of Chinese Journal of Practical Pediatrics, organized experts to develop this updated consensus. The consensus focuses on the definition, diagnostic approaches, risk stratification, and management of pediatric HCM,with the aim of improving the standardization of diagnosis and treatment of pediatric HCM, thereby enhancing its quality of life and improving prognosis.

Objective　To establish reference ranges for left ventricular functional parameters in neonatal echocardiography across different postnatal time intervals，stratified by gestational age（GA），birth weight，and gender，thereby providing reference for left ventricular functional assessment in the application of neonatal critical care bedside cardiac ultrasound. Methods　This multicenter，prospective，observational study enrolled 406 term neonates hospitalized or receiving outpatient care at the Children’s Hospital of Chongqing Medical University，Yinchuan First People’s Hospital of Ningxia Autonomous Region，and Inner Mongolia Maternal and Child Health Hospital between June 2023 and May 2024. Bedside echocardiography was performed by trained neonatologists or sonographers to measure parameters reflecting left ventricular systolic and diastolic function. Reference ranges（95% confidence intervals）were established for postnatal days 1，3，7，14，and 28，with stratification by GA and birth weight. Results　Among the 406 term neonates（204 males，202 females），mean GA was（38.9±1.5）weeks，and mean birth weight was（3197.8±449.5）g. Multiple left ventricular functional parameters—including left ventricular outflow tract stroke volume（LVO），weight-indexed LVO（LVO*），mitral annular plane systolic excursion（MAPSE），mitral valve early（MV-E）and late（MV-A）diastolic inflow velocities，and pulmonary vein S/D ratio—showed significant associations with birth weight and GA（all P<0.05）. LVO，LVO*，MV-E，MV-A，MV-E/e’ratio（early diastolic inflow velocity to lateral mitral annular tissue Doppler e’velocity），pulmonary vein S-wave velocity，and pulmonary vein S/D ratio were correlated with postnatal age（all P<0.05）. No parameters exhibited gender-related differences（all P>0.05）. Conclusion　Neonatal left ventricular systolic and diastolic functional parameters are associated with postnatal age，GA，and birth weight. This study establishes comprehensive reference ranges for left ventricular functional assessment，stratified by age，GA and birth weight，which play a crucial role in guiding refined hemodynamic evaluation and management of critically ill neonates.

Objective　High-dose methotrexate（HD-MTX）is a widely employed chemotherapy regimen for the treatment of medulloblastoma in pediatric patients.This study is aimed to investigate the risk factors associated with delayed methotrexate excretion and to evaluate the correlation between delayed excretion and the prognosis of the children. Methods　A 
retrospective analysis was conducted on children with medulloblastoma who received high-dose methotrexate（HD-MTX） treatment in the Department of Pediatrics of Beijing Shijitan Hospital，Capital Medical University between January 2019 and December 2020.Clinical data were collected，including gender，age at onset，histological type，molecular subtype，and disease stage.Additionally，24-hour（C24）and 42-hour（C42）blood drug concentrations，as well as blood routine and liver and kidney function indices，were recorded.The Mann-Whitney U test and Kruskal-Wallis H test were used to analyze the differences in blood drug concentrations across various clinical characteristics.Logistic regression analysis was employed to identify risk factors associated with delayed drug excretion. Furthermore，univariate and multivariate survival analyses were conducted using the Cox proportional hazards model. Results　A total of 41 children（24 boys，17 girls）with medulloblastoma were enrolled in this study，with a median age of 2.9 years（ranging from 0.6 to 13.6 years） at diagnosis.A total of 167 HD-MTX chemotherapy sessions were conducted，of which 31 sessions （18.6%）exhibited delayed excretion. Intrathecal MTX injection was performed in 133 sessions（80%）.C24 levels were significantly elevated in children who did not receive intrathecal injection（P=0.017）and those with leukopenia（P=0.044），and C42 levels were significantly elevated in children aged 3 years or older（P=0.006）and those with cerebrospinal fluid metastasis（P<0.001）.No statistically significant difference in adverse reactions was observed between children with normal excretion and those with delayed excretion. Cerebrospinal fluid metastasis was identified as an independent risk factor for delayed excretion in children with medulloblastoma（P=0.002，OR=4.864，95% CI 1.797 - 13.167）.Delayed MTX excretion was not a factor affecting the prognosis of children with medulloblastoma. Conclusion　The HD-MTX treatment exhibits favorable safety in pediatric patients with medulloblastoma. Cerebrospinal fluid metastasis is identified as a risk factor for delayed MTX excretion；however，the delayed excretion does not have a significant impact on the prognosis of the children.