Abstract: Electrical storm is a life-threatening condition characterized by recurrent ventricular arrhythmias. Despite aggressive medical therapy some patients remain refractory to treatment. The use of percutaneous left stellate ganglion block (LSGB) has shown promise in managing electrical storm. We present our early promising experience using LSGB in three patients with drug-refractory electrical storm, leading to stabilization until subsequent ventricular tachycardia (VT) ablation or successful anti-arrhythmic therapy.

Methods: One electrophysiologist in our team attended a one-day workshop at IRCCS Policlinico San Matteo (Pavia) to learn how to perform the SGB via the anatomical and the echo-guided technique. After that, during the years 2022-2023 three patients diagnosed with electrical storm, unresponsive to conventional anti-arrhythmic therapy, were considered for percutaneous LSGB. The blockade technique which was chosen was always the anatomic technique which was carried out at the bed of the patient in different settings (emergency room, cardiology ward, intensive care unit). Xylocaine or Mepivacainhydroclorid was injected into the neck with local anesthetic spread in the vicinity of the left stellate ganglion. Data were collected prospective including clinical characteristics, immediate and long- term outcomes and procedure-related complications.

Results: The included patients were two males (aged 64 and 76 years) and a female (aged 83 years), all with  a severely reduced left ventricular ejection fraction. All patients showed a drug-refractory (at least non responsive to one or more anti-arrhythmic agents) electrical storm with recurrent monomorphic ventricular arrhythmias two of them caused by a chronic ischemic cardiopathy and one in the setting of dilative cardiomyopathy. All three patients where free of sustained ventricular arrhythmias within 5 minutes from the percutaneous injection and only one of them had recurrent ventricular arrhythmias needing a second LSGB for rhythm control after five days. None of the three patients showed Horner syndrome after the injection and within the subsequent 5 hours of monitoring.  None of the patients needed a bilateral SGB. All three patients could safely be stabilized until the planned VT ablation or the beginning of an effective anti-arrhythmic therapy, carried out respectively two, four and twelve day after the first LSGB

Conclusion: Percutaneous LSGB appears to be a safe and effective adjunctive therapy which can be performed bedside in patients with drug-refractory electrical storm. This technique, combined with conventional antiarrhythmic therapy, offers a temporary respite from the recurrent ventricular arrhythmias, allowing for subsequent invasive treatment such as VT ablation.  Our monocentric early experience highlights the feasibility of the anatomical LSGB after a one-day training, making this technique attractive for other emergency situations such as its use in the emergency room, during out-of-hospital resuscitations by recurrent ventricular fibrillation or during complex percutaneous procedures such as ablations and coronarographies on electrical unstable patients.  Further research is warranted to validate these findings and determine the safety and feasibility of LSGB in a larger patient population as well as the feasibility of the training of doctors outside the electrophysiology field.