Connolly SJ, Dorian P, Roberts RS, et al. Comparison of [latin sharp s]-blockers, amiodarone plus [latin sharp s]-blockers or sotalol for prevention of shocks from implantable cardioverter defibrillators. JAMA. 2006; 295:165-171.

Amiodarone plus a beta-blocker may prevent painful shocks-appropriate and inappropriate-that occur with implantable cardioverter defibrillators (ICDs). In this study, researchers assessed the occurrence of ICD shocks in 412 patients who were randomized to receive amiodarone plus a beta-blocker (either metoprolol, carvedilol, or bisoprolol), sotalol alone, or a beta-blocker alone for 1 year. All of the patients had an ICD with antitachycardia pacing. Treatment with amiodarone plus a beta-blocker and, to a lesser extent, sotalol reduced the risk of shocks relative to beta-blocker alone. The annual cumulative percentages of patients experiencing an ICD shock with these treatments were, respectively, 10.3%, 24.3%, and 38.5%. The rates of inappropriate shocks in the corresponding groups were 3.3%, 9.4%, and 15.4%. Amiodarone plus beta-blocker cut the risk of shocks by 73% and 57% compared with beta-blocker alone, which fell just short of statistical significance. Pulmonary and thyroid side effects, as well as symptomatic bradycardia, were more common with amiodarone plus beta-blocker than with the other treatments. Drug discontinuation rates ranged from 5.3% for beta-blocker alone to 18.2% with amiodarone and 23.5% for sotalol. The results support the use of amiodarone plus beta-blocker for preventing shocks in patients with an ICD.