Abstract : Tetralogy of Fallot (ToF) cases with late presentation were more common than previously realized and often undetected despite proper screening. This population initially has a small degree of right ventricular outflow obstruction, allowing them to receive better oxygenation. The incidence of ToF in NCCHK from 2019–2021 was 883 cases. The palliative interventions which aim to increase pulmonary blood flow are still considered the first-choice treatment in patients with critical ToF unsuitable for primary repair. RVOT stent (Right Ventricular Outflow Tract Stent) is frequently used to increase pulmonary artery flow in patients with uncorrected ToF in preparation for a ToF repair. It has been advocated as an intermediary step for high-risk patients. To report a case of late-presentation ToF with LV dysfunction which performed non-surgical palliative approach as bridging procedure due to high risk of surgery. A 7-year-old boy presented to the emergency room (ER) with shortness of breath and cyanosis. The patient has been diagnosed as ToF since 2019 but has lost follow-up due to the COVID-19 pandemic. Echocardiography on admission revealed a decreased left ventricular (LV) ejection fraction (LVEF of 39.5%) with global hypokinetic and thrombus at LV. Two days after admission, a joined cardiology–cardiothoracic surgery meeting was decided to do MSCT Cardiac and right ventricle outflow tract (RVOT) stenting for the patient. The day before being scheduled for MSCT and RVOT stenting, the patient suddenly developed a hypercyanotic spell and fell into cardiac arrest. The Code Blue protocol was activated and the patient was promptly given CPR, intubated, and transported to the ICU. He was having episodes of Arrest-ROSC. The patient was promptly delivered to the Cath lab for emergency right ventricular outflow tract (RVOT) stenting. At the end of the procedure, oxygen saturation reached 92% with stable hemodynamics and the RV-PA gradient was substantially decreased from 101 mmHg to 28 mmHg (evaluated by echocardiography). After RVOT stenting, the patient’s clinical condition continued to gradually improve. Echocardiography evaluation showed marked improvement in systolic function (EF 70%). We reported a case with late-presentation ToF patients with LV dysfunction who were treated with a non-surgical palliative approach as a bridging procedure in high-risk for surgery. The patient’s condition gradually improved after the RVOT stent procedure.