Objective ·To analyze the occurrence of heart failure (HF) and related functional impairment items in 3?6-year-old children with congenital heart disease (CHD) in the first year after operation by using the Rasch model. Methods ·The children aged 3?6 years old who were followed up at Shanghai Children 's Medical Center, Shanghai Jiao Tong University School of Medicine, from February to August 2021 were included. The general information of children, the evaluation of International Classification of Functioning, Disability, and Health for Children and Youth core set for children with congenital heart disease after surgery (ICF-CY-CHDS) filled by their parents and the diagnosis of HF were collected. The analysis with Rasch model was carried out by using Winsteps 3.72.3 software, and the degree of postoperative functional impairment and the difficulty of the items of the ICF-CY-CHDS were transformed into the same evaluation system (Logit value) for comparison. Multivariate Logistic regression was used to analyze the items related to HF. Results ·A total of 340 CHD children after surgery were included. The average age of the children was (4.48±1.05) years old and their average follow-up time was (8.33±2.79) months after CHD surgery. According to the analysis of Rasch model, the overall difficulty of the items of the ICF-CY-CHDS was moderate (the Logit value was 0), which was suitable for the study population. The Logit value of the overall functional impairment of 340 children was -2.35±0.87, indicating that the overall rehabilitation level of the children after CHD surgery in the first year was good; Among them, 24 children (7.1%) had HF, and the overall functional impairment of the children with HF was significantly more serious than that of the children without HF ( P=0.000). After transforming the degree of postoperative functional impairment and the difficulty of the items of the ICF-CY-CHDS into the same evaluation system, it was found that the proportions of the children failing to reach the standards in 9 items were higher in the HF children than those in the non-HF ones. The 9 items were “b1302 appetite” ( P=0.014), “b152 emotional functions” ( P=0.014), “b435 immunological system functions” ( P=0.000), “b455 exercise tolerance functions” ( P=0.014), “b530 weight maintenance functions” ( P=0.000), “b560 growth maintenance function” ( P=0.000), “d160 focusing attention” ( P=0.001), “e450 individual attitudes of health professionals” ( P=0.001), and “e580 health services, systems and policies” ( P=0.000). The results of multivariate Logistic regression demonstrated that “e580 health services, systems and policies” was the item related to HF ( OR=13.250, 95% CI 4.905?35.795). Conclusion ·The overall rehabilitation level of the children with CHD in the first year after surgery is good, but there are still a few children with HF. Making corresponding health service strategies about children 's psychological behavior, cardiopulmonary function, nutritional status, and medical environment may be helpful to improve children 's postoperative cardiac rehabilitation level and reduce the occurrence of HF.