An overview of antiarrhythmic drug management of electrical storm.

Electrical storm, the most lethal of all cardiac arrhythmias, is defined as incessant or frequently recurrent ventricular fibrillation, or hemodynamically destabilizing ventricular tachycardia. Electrical storm typically develops in older men with coronary artery disease, in the setting of a acute myocardial infarction or following cardiac surgery. Treatment of electrical storm with conventional antiarrhythmic drugs is seldom effective. Amiodarone, an anti-arrhythmic agent with established efficacy in the treatment of a variety of atrial and ventricular tachyarrhythmias, is now available as an intravenous formulation in hospitals. Three recent studies have examined the effect of intravenous amiodarone in the management of electrical storm. The studies, performed in critically ill patients, found amiodarone to be effective in the treatment of these serious arrhythmias. Two of the studies compared different dose ranges for intravenous amiodarone, while one study compared amiodarone to intravenous bretylium. The investigators found amiodarone to be as effective as bretylium, and to have significantly fewer adverse effects requiring drug discontinuation. Side effects of intravenous amiodarone included hypotension and bradycardia, both of which were managed by reducing the rate of the infusion. Proarrhythmia, defined as torsade de pointes or new onset ventricular fibrillation, was infrequently seen in the studies.