Concomitant amiodarone and the implantable cardioverter-defibrillator: is there a place?

OBJECTIVE: To discuss the controversy surrounding concomitant therapy with amiodarone and the implantable cardioverter-defibrillator (ICD). DATA SOURCES: A MEDLINE search identified English-language literature sources, including nonhuman studies. STUDY SELECTION: Studies included those that specifically addressed the use of amiodarone plus the ICD as well as reviews of the ICD. DATA EXTRACTION: Studies were evaluated for design, type of defibrillation electrode or defibrillator, method of defibrillation, amiodarone loading and maintenance dosages, duration of amiodarone therapy, and study endpoints. DATA SYNTHESIS: Because the ICD functions by delivering energy to depolarize a mass of myocardium, concomitant use of antiarrhythmic agents that elevate the defibrillation threshold (DFT) beyond an ICD's energy capability may adversely effect patient outcome. Amiodarone has been shown to both increase and decrease the DFT. Trials examining the use of amiodarone plus the ICD have not provided strong evidence that amiodarone will decrease the number of ICD discharges or favorably affect the mortality rate. Amiodarone is also expensive and toxic. Although the cost of the ICD is relatively high, continuing improvements in battery life will decrease long-term costs. CONCLUSIONS: Controlled trials are required to substantiate the improved survival rate with the ICD and to determine the role of antiarrhythmic agents in conjunction with the device. At present, there are no data to support the combination of amiodarone and an ICD in terms of improved quality or duration of life.