Study Evaluating Dexmedetomidine in the Acute Treatment of Electrical Storm

Electrical storm (ES), defined as three or more sustained or treated ventricular arrhythmias in a 24-hour period, is a life-threatening condition that is associated with significant short- and long-term mortality. Autonomic dysfunction from increased sympathetic tone and the catecholamine surge from defibrillator shocks can precipitate recurrent ventricular arrhythmias and exacerbate ES. Although the mainstay of treatment are anti-arrhythmic drugs, sedative agents and procedures are commonly used to decrease sympathetic tone. These therapies have been studied in refractory ES but the benefit of early sedation remains unclear.

Alpha-2 agonism with dexmedetomidine can provide conscious sedation without the need for mechanical ventilation. Dexmedetomidine has been found to reduce ventricular arrhythmia events in non-ES patients in the intensive care unit and in the peri-operative period. Its antiarrhythmic properties are thought to be due to catecholamine suppression, prolonging electrical refractory periods, and increasing vagal tone. Its rapid onset and favorable safety profile render alpha-2 agonism with dexmedetomidine a potentially valuable therapy for patients with ES.

This study is a multi-centre, double-blinded, placebo-controlled, randomized trial that will evaluate the effectiveness of dexmedetomidine in the acute treatment of ES. Consecutive patients admitted to an intensive care unit will be randomized to receive dexmedetomidine or placebo at the time of presentation. The study drug will be titrated to a maintenance dose and continued for 48 hours before being weaned.

Inclusion criteria

• All patients admitted to an intensive care unit with electrical storm over the age of 18 years will be approached for enrollment.

Exclusion criteria

• Refractory shock lasting for more than 30 minutes unrelated to ventricular arrhythmias (VAs), defined as requiring two or more vasopressors
• SCAI class D or E cardiogenic shock
• Cardiac arrest(s) with a no-flow and low-flow total time of greater than 10 minutes prior to recruitment.
• ST-segment elevation myocardial infarction (STEMI)-induced VA with signs of active ischemia.
• Bradycardia with heart rate less than 40 beats per minute, bradycardia-induced ventricular tachyarrhythmia, second degree Mobitz type 2 or greater atrioventricular block in the absence of a pacemaker.
• Pregnancy
• Known dexmedetomidine allergy or intolerance
• Inability to obtain consent from patient or substitute decision maker.
• Patients who have received dexmedetomidine or clonidine during the 24 hours prior to randomization