Abstract
<title>Abstract</title> <p>Background Refractory electrical storm following acute myocardial infarction (AMI) is a life-threatening condition with limited treatment options when conventional pharmacotherapy and electrical cardioversion fail. Stellate ganglion block (SGB) has emerged as a rescue intervention to reduce cardiac sympathetic tone. However, the use of dexmedetomidine as an adjuvant to local anesthetics for SGB in this setting has rarely been reported. Case presentation A 46-year-old female patient was admitted to hospital with an acute myocardial infarction (AMI), complicated by cardiogenic shock. The patient required veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and intra-aortic balloon pump (IABP) support following percutaneous coronary intervention. Despite the administration of deep sedation, beta-blockade, and antiarrhythmic therapy, the patient exhibited recurrent ventricular fibrillation (VF) that proved refractory to multiple electrical cardioversions. Following a multidisciplinary discussion, ultrasound-guided left subarachnoid block (SGB) was performed using an in-plane technique at the C6 transverse process level. The first SGB with 4 mL of 0.75% lidocaine resulted in Horner's syndrome and markedly reduced VF frequency. However, VF recurred approximately 48 hours later. A second SGB was then performed using a mixture of 4 mL of 0.75% lidocaine and 0.5 µg/kg of dexmedetomidine at the same site. Following the second block, VF ceased entirely, with only occasional premature ventricular contractions and self-terminating short runs of ventricular tachycardia. The patient was successfully weaned from VA-ECMO one week later, extubated, and discharged home after one month with full recovery. Conclusion This case demonstrates that ultrasound-guided SGB with lidocaine combined with dexmedetomidine may provide effective suppression of refractory electrical storm in patients on maximal mechanical and pharmacological support. The staged response in this case suggests that the combination of lidocaine with dexmedetomidine may provide more durable antiarrhythmic efficacy, though larger prospective studies are required to confirm its safety and effectiveness. Registration Clinical trial number: not applicable.</p>