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What’s the Best Drug Therapy for Preventing ICD Shocks?

Amiodarone plus beta-blockade — but that’s not the whole story.

Implantable-cardioverter defibrillators (ICDs) prolong the survival of many patients by delivering lifesaving, though painful, shocks for ventricular tachycardia (VT) or ventricular fibrillation (VF). In addition to these appropriate shocks, ICDs sometimes deliver unnecessary shocks for atrial arrhythmias. By suppressing arrhythmias, antiarrhythmic drugs have the potential to prevent the need for lifesaving shocks and to avoid unnecessary shocks. But do they perform any better than standard beta-blocker therapy alone?

Researchers addressed this question in an international trial involving 412 patients (mean age, 64; 80% men; maximum LV ejection fraction, 40%) who had recently received St. Jude Medical dual-chamber ICDs for inducible or spontaneous VT or VF. Subjects were randomized to receive standard beta-blocker therapy alone, sotalol alone, or standard beta-blocker therapy plus amiodarone for 1 year.

Incidence of the primary endpoint — the first occurrence of any ICD shock — was significantly lower in the amiodarone group (10.3%) than in the sotalol group (24.3%) or the standard-therapy group (38.5%). The difference between the sotalol and standard-therapy groups did not quite reach significance. Results were similar for appropriate and inappropriate shocks. Notably, amiodarone recipients experienced more adverse pulmonary events, thyroid events, and symptomatic bradycardia than the other groups did.

Comment: These results validate what physicians who care for large numbers of ICD patients already know: Amiodarone effectively prevents many ICD shocks. However, enthusiasm for using amiodarone for this purpose must be balanced against its risk for important short- and long-term side effects. Also, we don't know (1) how sotalol plus standard beta-blocker therapy would have performed against amiodarone plus a beta-blocker or (2) how antiarrhythmic therapy would do against catheter ablation for preventing ICD shocks.

— Hugh Calkins, MD

Published in Journal Watch Cardiology February 2, 2006

Citation(s):

Connolly SJ et al. for the Optimal Pharmacological Therapy in Cardioverter Defibrillator Patients (OPTIC) Investigators. Comparison of ß-blockers, amiodarone plus ß-blockers, or sotalol for prevention of shocks from implantable cardioverter defibrillators. The OPTIC Study: A randomized trial. JAMA 2006 Jan 11; 295:165-71.

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Page RL. Antiarrhythmic drugs for all patients with an ICD? JAMA 2006 Jan 11; 295:211-3.

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• Medline abstract (Free)