Background: Left ventricle-right atrium (LV-RA) connection may develop secondary to ventricular septal defect (VSD) repair, particularly when the membranous septum or tricuspid valve is affected, leading to a leaflet defect. While surgery remains the standard treatment, reports of transcatheter valve closure are limited. This highlights the importance of exploring the safety and feasibility of transcatheter approaches for LV-RA connection, especially in high-risk patients. Case presentation: This is the first reported case of a retrograde Konar-MF closure of an LV-RA connection on a 6-year-old male patient with a history of VSD surgery. Pre-procedural transesophageal echocardiography (TEE) showed a 4 mm defect in the septal leaflet of the tricuspid valve. A residual membranous septal aneurysm (MSA) extending from the subaortic region to the septal annulus of the tricuspid valve without residual shunt, and a small atrial septal defect (ASD) were also identified. The cardiac team performed closure using Konar-MF VSD Occluder No. 6/8 mm via a retrograde right femoral arterial approach, advancing the catheter through the left ventricle and across the defect. A well-positioned device with minimal residual central shunt and without peripheral leakage were confirmed from the post-procedural TEE. Clinical evaluation immediately after procedure and at 3-month follow-up demonstrated good results. Conclusion: Percutaneous transcatheter device closure of an LV-RA connection in pediatrics is a feasible alternative to surgery using a retrograde technique. 2026 Sakti, Kurniawati, Ariani, Lasanudin and Prakoso.