Stellate Ganglion Neuromodulation for the Treatment of Electrical Storm

Ventricular tachycardia (VT) is a serious heart rhythm problem in which the heart beats very fast and in an abnormal way. These abnormal heart rhythms can be life-threatening. When a person has three or more episodes of VT within a 24-hour period, it is called a "VT storm." VT storm can be difficult to treat because some patients do not respond well to standard medications. Some studies suggest that a procedure called a stellate ganglion block (SGB) may help. An SGB involves injecting a local anesthetic near a group of nerves in the neck that help control signals between the brain and the heart. The procedure can be performed at the bedside using ultrasound guidance. The purpose of this study is to find out whether SGB can delay or prevent the return of dangerous abnormal heart rhythms in patients with VT storm who are receiving care in an intensive care unit. If a patient joins the study, they will be randomly assigned (by chance, like flipping a coin) to one of two groups. One group will receive a real stellate ganglion block. The other group will receive a sham procedure, in which a blunt needle will touch the skin but no injection will be given. Patients in the sham group who continue to experience VT may later receive the real procedure. Participants will be followed until they leave the hospital or for 30 days after joining the study, whichever comes first. The study will take place at five hospitals across Ontario.

Inclusion Criteria: 1. Age ≥18 years 2. ≥3 VT/VF episodes within 24 hours (including appropriate shock or antitachycardia pacing (ATP) terminated events) VT/VF episode definition: ventricular tachyarrhythmia episode ≥30 seconds in duration (VT or VF) requiring intervention regardless of duration, as captured on telemetry, ECG or device intracardiac electrogram. 3. \