Objective: Congenital Long QT Syndrome (LQTS) is a rare channelopathy associated with malignant arrhythmias and sudden cardiac death. This case report aims to highlight the role of Left Cardiac Sympathetic Denervation (LCSD) as a rescue therapy in neonates with drug-refractory LQTS. Methods: We present the case of a female neonate diagnosed with congenital LQTS type 8 (Timothy syndrome), complicated by 2:1 atrioventricular block and recurrent torsades de pointes despite pacemaker implantation, beta-blockade, mexiletine, and magnesium. Due to persistent arrhythmias and a transient response to left stellate ganglion block, LCSD was performed via thoracotomy. Results: The surgery involved resection of the left stellate ganglion and thoracic ganglia T2–T4 through a left thoracotomy approach. The immediate postoperative course was uneventful. Genetic analysis confirmed a CACNA1C mutation. Despite the intervention, the patient died on postoperative day seven due to progressive cardiac failure. Conclusion: This case underscores the potential role of LCSD in severe neonatal LQTS unresponsive to conventional therapy. However, its efficacy appears to depend heavily on genetic subtype and timing of intervention. Early genetic testing and timely surgical decision-making may improve outcomes in such high-risk patients. Further investigation is needed to determine optimal indications and timing for LCSD in neonates with LQTS.