Background: The most frequent type of cardiac abnormality in childhood is left-to-right shunting in acyanotic congenital heart disease (CHD). Delays in CHD care are caused by limited access to professional health services. Limited facilities, delayed diagnosis, and family economic factors all make it difficult to close the shunt in a timely manner, increasing the patient's risk of developing pulmonary hypertension. Objective: To determine the factors that influence pulmonary hypertension in pediatric patients with left to right shunting in acyanotic congenital heart diseases. Materials and Methods: This observational study was included children with acyanotic CHD left-to-right shunting who were admitted in the Department of Pediatric Cardiology in Bangladesh Shishu Hospital & Institute (BSHI), Dhaka, from 1st January to 31st December 2024. Total 140 patients aged between 1 month to 17 years with isolated atrial septal defect, or ventricular septal defect, or patent ductus arteriosus were included. Patients who had abnormalities that limited blood flow to the lungs, such as pulmonary stenosis, disorders that limited systemic blood flow such as aortic stenosis, aortic coarctation, mitral stenosis, as well as patients with rheumatic heart disease, cardiomyopathy, and infective endocarditis were excluded. Results: Younger children are more likely to develop pulmonary hypertension (p < 0.05). About four-fifth 55 (78.57%) of the participants had single congenital anomaly. Out of the remaining 6 (8.57%) children ASD e PDA was 4 (5.71%), ASD and VSD was 3 (4.29%), VSD e PDA was 3 (4.29%) respectively. Heart failure was substantially higher in the pulmonary hypertension group compared to the no pulmonary hypertension group (42.86% vs. 10%, p<0.001). The findings revealed that heart failure was a strong predictor of pulmonary hypertension, with a hazard ratio of 4.1. Conclusion: Patients with acyanotic CHD and heart failure who underwent left-to-right shunting have a four-...