Use of a combination of class III and class Ic antiarrhythmic agents in patients with electrical storm.

STUDY OBJECTIVE: To determine the efficacy of the combination of class III and class Ic antiarrhythmic agents in suppressing an electrical storm in patients with and without a transvenous implantable cardioverter-defibrillator (ICD).

DESIGN: Retrospective medical record review.

SETTING: Arrhythmia service of an academic medical center in Zerifin, Israel.

PATIENTS: Ten patients who experienced an electrical storm that was not effectively treated with amiodarone or sotalol monotherapy between December 15, 1999, and June 13, 2007.

MEASUREMENTS AND MAIN RESULTS: The medical records of 152 patients who received an ICD during the study period were reviewed. Twenty patients experienced an electrical storm, an arrhythmia defined as more than two episodes of hemodynamically unstable ventricular tachycardia during a 24- hour period. Ten of the 20 patients responded favorably to amiodarone or sotalol monotherapy (class III antiarrhythmics), but in 10 patients, the combination of a class III and a class Ic antiarrhythmic agent was needed to effectively eliminate the electrical storm. Of the 10 patients who required both agents, two (20%) developed an electrical storm before implantation of their ICD. In another patient who had ongoing ischemia, ventricular tachycardia recurred, but the drug combination decreased the number of ventricular arrhythmia episodes. One patient with dilated cardiomyopathy had one recurrence of ventricular tachycardia, which was terminated with antitachycardia pacing. Three patients died during a mean +/- SD follow-up of 8.7 +/- 9.9 months.

CONCLUSION: Electrical storm can be acutely treated with the combination of a class III and a class Ic antiarrhythmic agent when a class III agent alone is insufficient and when radiofrequency ablation is not an option. Patients receiving this drug combination can be discharged from the hospital only if they have an ICD.