BACKGROUND Left cardiac sympathetic denervation (LCSD) is a surgical procedure that has been shown to have an antiarrhythmic and antifibrillatory effect. Evidence indicating its antiarrhythmic effect has been available for over 100 years. It involves the removal of the lower half of the stellate ganglion and T2-T4 of the sympathetic ganglia and is carried out as either a unilateral or bilateral procedure. With advancements in thoracic surgery, it can be safely performed via a minimally invasive Video-Assisted Thoracoscopic Surgery (VATS) approach resulting in significantly less morbidity and a shortened inpatient stay. LCSD provides a valuable treatment option for patients with life-threatening channelopathies and cardiomyopathies. AIMS AND METHODS This case series reports the preliminary paediatric and adult experience in the Republic of Ireland with LCSD and describes five cases recently treated in addition to an outline of the operative procedure employed. Of the five cases included, two were paediatric cases and three were adult cases. RESULTS One of the paediatric patients had a diagnosis of the rare catecholaminergic polymorphic ventricular tachycardia (CPVT) and the other a diagnosis of long-QT syndrome. Both paediatric patients experienced excellent outcomes. Of the three adult patients, two benefitted greatly and remain well at follow-up (one inappropriate sinus tachycardia and one CPVT). One patient with idiopathic ventricular fibrillation unfortunately passed away from intractable VF despite all attempts at resuscitation. CONCLUSION In this case series, we highlight that LCSD provides a critical adjunct to existing medical therapies and should be considered for all patients with life-threatening refractory arrhythmias especially those patients on maximal medical therapy.