Implanted Defibrillator Reduces Heart Failure Deaths

A new study has shown that an implantable cardiac defibrillator (ICD) significantly reduces deaths among heart failure patients. Another finding was that treatment with amiodarone, an antiarrhythmic drug, does not reduce deaths. These results were presented at the annual meeting of the American College of Cardiology in New Orleans (LA, USA).

The study, involving 2,521 participants, tested whether an ICD that provides a shock without pacing impulses or whether an antiarrhythmic drug would help prevent sudden death in heart failure patients. The participants were divided into three roughly equal-sized groups: a placebo group, an amiodarone group, and an ICD group. The mean follow-up was almost four years. The participants had moderate-to-severe heart failure and ranged in age from 19-90. About 52% had heart failure caused by heart attack, and the other 48% had heart failure due to a different cause, such as a viral infection of the heart. While 30% had diabetes, 15% had had at least one episode of diagnosed atrial fibrillation.

Study results showed 666 deaths overall: 182 (22%) in the ICD group, 240 (28%) in the amiodarone group, and 244 (29%) in the placebo group. The benefit from ICD therapy appeared to be strongest in those patients with moderate heart failure, while amiodarone appeared to have a detrimental effect in those with severe heart failure. ICD therapy reduced deaths whether heart failure was caused by a heart attack or something else.

"Until now, it was not known if implanted defibrillators would help such a wide range of heart failure patients, including those whose heart failure may not have been caused by a heart attack,” noted Dr. Barbara Alving, acting director of the U.S. National Heart, Lung, and Blood Institute (NHLBI, Bethesda, MD, USA), which sponsored the study.




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