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Implantable Cardioverter-Defibrillator Is More Effective in Treating Congestive Heart Failure Than Amiodarone Therapy 

January 20, 2005

Seattle, WA In patients with NYHA class II or III congestive heart failure implantable cardioverter-defibrillator therapy reduces mortality, while amiodarone has no favorable effect. A randomized, double-blind trial of amiodarone and ICD therapy was performed and published by Gust H. Bardy, et. al, from the Seattle Institute for Cardiac Research in the January 20, 2005 issue of the New England Journal of Medicine. This study compared the effects of amiodarone versus ICD therapy on mortality in patients with congestive heart failure and found that only ICD therapy conferred a significant benefit when compared with placebo. 

Both treatment with amiodarone and ICD therapy have been proposed to improve the prognosis in patients with congestive heart failure, but prior to this study neither had been directly compared in a randomized, double blind, placebo controlled clinical trial. 

The study randomization period began in September 1997 and ended in July of 2001, during which 2,521 patients were randomized to receive either placebo, amiodarone, or a single chamber ICD. Patients had to have NYHA class II or III heart failure with a left ventricle ejection fraction of no greater than 35 percent. Of these patients, 847 were assigned to placebo, 845 to amiodarone, and 829 to ICD therapy. The primary endpoint of the trial was death from any cause. Placebo and amiodarone were administered in a double blind fashion. The ICDs were uniformly programmed to have a detection rate of 187 beats per minute or more. 

Out of the 829 patients in the ICD group, 259 (31 percent) were known to have received shocks from their device for any cause. During the five years of follow-up, the average annual rate of ICD shocks was 7.5 percent. 

A total of 666 patients died: 244 (29 percent) in the placebo group, 240 (28 percent) in the amiodarone group, and 182 (22 percent) in the ICD group. As compared with placebo, amiodarone therapy was associated with a similar risk of death (hazard ratio, 1.06; 97.5 percent confidence interval 0.86 to 1.30; P=0.53) and ICD therapy was associated with a decreased risk of death (hazard ratio, 0.77; 97.5 percent confidence interval 0.62 to 0.96; P=0.007). 

Interestingly, patients who had NYHA class II heart failure showed a greater benefit from ICD therapy, while patients with NYHA class III heart failure did not show a benefit significantly greater than placebo with the ICD therapy.  

These results indicated that for this patient population, ICD therapy is effective in decreasing mortality, while amiodarone does not appear to offer any benefit when compared with placebo controls. 

Co-authors: Kerry L. Lee, Ph.D., Daniel B. Mark, M.D., Jeanne E. Poole, M.D., Douglas L. Packer, M.D., Robin Boineau, M.D., Michael Domanski, M.D., Charles Troutman, R.N., Jill Anderson, R.N.,

George Johnson, B.S.E.E., Steven E. McNulty, M.S., Nancy Clapp-Channing, R.N., M.P.H., Linda D. Davidson-Ray, M.A., Elizabeth S. Fraulo, R.N., Daniel P. Fishbein, M.D., Richard M. Luceri, M.D., and John H. Ip, M.D. 

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