Percutaneous Stellate Ganglion Block with Bupivacaine/Lidocaine vs Amiodarone in Patients with Electrical Storm: Randomized STAR‑2 Trial

The primary objective is to determine whether the efficacy of percutaneous stellate ganglion block, measured by the proportion of patients achieving complete suppression of the treated ventricular arrhythmia within the first three hours post‑treatment, is superior to that of intravenous amiodarone, the current standard of care, in individuals experiencing an electrical storm.

The trial enrolled adult participants aged 18 years or older, encompassing both female and male patients. Individuals were selected on the basis of experiencing an electrical storm defined by at least three episodes of fast ventricular tachycardia or ventricular fibrillation treated with internal or external defibrillation within the 12 hours preceding randomization, with a minimum of one episode occurring in the three hours prior to enrolment. Eligible subjects presented with any structural heart disease, acute or chronic coronary disease, or catecholaminergic polymorphic ventricular tachycardia. The sponsor did not provide information regarding the total number of participants enrolled in the study.

The STAR 2 study is a multicentre, randomized, controlled trial evaluating percutaneous stellate ganglion block (PSGB) as first‑line therapy compared with intravenous amiodarone in patients experiencing electrical storm. Eligible participants (age ≥ 18 years, ≥ 3 episodes of fast ventricular tachycardia/ventricular fibrillation treated by internal or external defibrillation within the preceding 12 hours, with at least one episode in the last three hours, and underlying structural heart disease, coronary disease, or CPVT) undergo a screening visit to confirm inclusion and exclusion criteria. Upon confirmation, subjects are randomized to receive either PSGB using a mixture of lidocaine (600 mg) and bupivacaine (150 mg) administered paravertebrally, or a comparator dose of amiodarone (1200 mg) given intravenously. The primary efficacy assessment is performed during a three‑hour observation period after treatment, measuring the proportion of patients with complete suppression of treated ventricular arrhythmias. Subsequent follow‑up visits monitor safety, arrhythmia recurrence, and overall clinical status until discharge, after which an end‑of‑study visit is conducted to collect final outcome data. Participant involvement extends from the screening encounter through the end‑of‑study assessment, with early termination permitted for safety concerns, serious adverse events, or substantial protocol deviations. Recruitment is planned to commence in May 2026 and conclude in May 2028.

The comparator arm utilizes amiodarone hydrochloride supplied as a 50 mg/ml solution for injection. The product is administered intravenously as a single bolus dose of 1200 mg (24 ml) infused over the prescribed time frame in accordance with the study protocol. Dosing is recorded in the case report form, and administration is verified by a second qualified investigator to ensure protocol adherence.

The experimental arm includes a paravertebral administration of lidocaine. Lidocaina Kabi is provided as a 20 mg/ml solution for injection, and a total dose of 600 mg (30 ml) is injected at the target vertebral level. The procedure is performed once per participant, and the volume injected is documented. Compliance is monitored by confirming the injection site, volume delivered, and timing relative to the onset of the electrical storm.

Additionally, the experimental regimen incorporates bupivacaine. BUPISEN is a 5 mg/ml solution for injection, with a single dose of 150 mg (30 ml) administered via the same paravertebral technique. The dose and administration time are captured in the electronic data capture system, and a compliance check is performed by the study coordinator to verify that the injection conforms to the predefined schedule.

Efficacy will be assessed by determining the proportion of patients with complete suppression of treated ventricular arrhythmia (VA) during the first three hours after treatment. The primary endpoint requires identification of any VA episodes that necessitate antitachycardia pacing (ATP), internal direct current (DC) shock, or external DC shock within this observation window.

Patients will be continuously monitored using standard cardiac rhythm surveillance equipment immediately following the percutaneous stellate ganglion block or intravenous amiodarone administration. All occurrences of treated VA, including the type of intervention applied (ATP, internal DC shock, or external DC shock), will be recorded in real time. The primary efficacy analysis will compare the percentage of patients achieving complete suppression of treated VA between the investigational and comparator groups.