Nada Al-Sakini,Daniela Bispo,Shreya Ohri,Wasyla Ibrahim,Cathy West,Michael Gatzoulis,Wei Li, The Forgotten Ventricle: Sub-Pulmonary LV Failure in a Patient with Transposition of the Great Arteries Post Atrial Switch Repair International Journal of Surgical Case Reports 2022 2674-4171 http://dx.doi.org/10.31487/j.IJSCR.2022.01.05 https://www.sciencerepository.org/the-forgotten-ventricle_IJSCR-2022-1-105 Abstract: We present the case of a patient with transposition of the great arteries (TGA) post atrial switch repair (Mustard) with a failing sub-pulmonary left ventricle. Our case highlights the importance of early identification of a failing sub-pulmonary LV and the significance of utilising multi-modality imaging in diagnosing and monitoring these patients. Similarly, it emphasizes the importance of a holistic approach in managing patients with complex physical and psychological needs in relation to timely transplantation referral.Keywords: Sub-pulmonary LV, systemic RV, mustard repair, transposition of the great arteries, heart failure, atrial switch operation