Percutaneous Blockade Protocol of the Stellate Ganglion in Patients With Refractory Electrical Storm

The study aims to evaluate the reduction of arrhythmic events following stellate ganglion blockade in patients with electrical storm refractory to initial clinical measures.

Hypothesis Stellate ganglion infiltration is an effective neuromodulation strategy for controlling arrhythmic events in patients with electrical storm awaiting definitive therapy.

Methodology This is a single-center randomized study investigating the efficacy of stellate ganglion blockade in patients with electrical storm refractory to initial clinical measures.

Participant Selection and Sample Size Participants will include patients admitted to the Emergency Unit or any Intensive Care Unit with a diagnosis of refractory electrical storm. Based on the STAR study, which reported a median of 6 arrhythmic events before SGB (IQR: 3 to 15.8), and aiming for at least a 50% reduction in arrhythmias in the active group post-procedure (with no expected change in the placebo group), a sample size of 32 patients per group was calculated (alpha = 0.05, power = 80%, two-tailed test).

Definitions Electrical storm (ES) is defined as three or more episodes of ventricular arrhythmias (including appropriate ICD therapies), separated by at least 5 minutes, within 24 hours. Refractory ES is defined as recurrent arrhythmias despite antiarrhythmic drug administration. Patients requiring discontinuation of antiarrhythmics due to adverse events will also be eligible for SGB. An arrhythmic event is defined as an episode of sustained VT or VF (>30 seconds or unstable), treated or not with antitachycardia pacing (ATP), electrical therapy, ICD shock, or external defibrillation. Pre-specified complications include: simple hematoma, hematoma requiring intervention, symptoms due to anesthetic absorption, brachial plexus injury, simple vascular injury, and vascular injury requiring intervention.