A Paradoxical Increase in Ventricular Arrhythmia After a Left Stellate Ganglion Block: A Case Report.

Ultrasound-guided left-sided or bilateral stellate ganglion block (SGB) has emerged as an effective bedside intervention for malignant ventricular arrhythmias (VA) refractory to conventional therapies, with demonstrated safety and efficacy in multiple studies. We report a medically complex patient with presumed genotype-negative Long QT Syndrome (LQTS) who experienced a sudden, transient increase in arrhythmic events shortly after an uncomplicated left-sided ultrasound-guided SGB. To our knowledge, this is the first documented case of increased VA burden following left-sided SGB, highlighting the potential for paradoxical effects and the need for cautious application in patients with comorbidities.