Background: Electrical storm is currently treated with anti-arrhythmic medications and/or ablation, with only modest benefit. We postulated that quinidine may be effective in terminating and preventing electrical storms.
Methods: We conducted a retrospective cohort study of consecutive advanced left-ventricular- dysfunction (LVD) patients during 2009-2014 who received oral quinidine for the treatment of electrical storms. Patients were followed for outcome of recurrent VT/VF, heart transplantation or ventricular-assist device implantation, and death.
Results: The 20 patients (80% male) with a mean age of 65.5±8.9, the mean left ventricular ejection fraction 26.7±6.9%, and 75% of ischemic etiology were followed for 10.6±16.8 months. 19 patients had an implanted internal defibrillator (ICD), 6 (30%) with concomitant cardiac resynchronization therapy (CRT) and 1 patient received an ICD in the index admission. Only 2 patients underwent VT ablation. At baseline the patients were treated with amiodarone (70%), d-sotalol (15%), and mexiletine (15%). Treatment with amiodarone was previously stopped due to thyrotoxicosis in 15% and due to treatment failure in 20%. During electrical storms, 65% of patients received intravenous therapies that included amiodarone alone (20%), procainamide alone (10%), a combination of both (15%), and lidocaine combined with amiodarone (20%). The remaining patients were treated with oral therapy alone. Quinidine was initiated with mean daily dose of 1087.5±238 mg. Seventeen patients (85%) were discharged from hospital, of whom 6 patients (36%) on quinidine alone and 11 patients (64%) with concomitant amiodarone (mean daily dose of 472.7±379.7 mg). Four patients (23.5%) had recurrent episodes of appropriate defibrillator discharge due to VT/VF, and 13 (76.5%) were apparently free of VT/VF during the follow-up period of 13.6±17.4 months. The composite outcome occurred in 8/20 patients (40%).
Conclusions: Oral quinidine, solely or with concomitant amiodarone therapy, seems to be effective in preventing or treating electrical storms in advanced LVD patients who have an ICD and are refractory to conventional treatments.
