Study Finds Limitation to ICD Benefit

A large study involving 73 sites in 12 countries has found that implantable cardioverter defibrillator therapy does not reduce overall mortality in high-risk patients who have recently had a heart attack, but the study also found that ICDs significantly reduced mortality in patients with arrhythmia.

The study, sponsored by St. Jude Medical, Inc. (St. Paul, MN, USA), was called DINAMIT (defibrillator in acute myocardial infarction trial). Patients in the study ranged in age from 18-80, with additional inclusion criteria being a heart attack within six to 40 days, a left-ventricular ejection fraction of less than or equal to 35%, and signs of impaired cardiac autonomic modulation. The results were reported in the December 9, 2004, issue of The New England Journal of Medicine.

While the results showed no reduction in total mortality, they also demonstrated that in this patient population, ICD therapy can significantly reduce the risk of sudden death in patients who have had a recent heart attack and are at high risk of arrhythmic death. St. Jude Medical is a developer and marketer of ICDs.

"Although ICD therapy in the DINAMIT study was associated with a large, statistically significant reduction in the rate of death due to arrhythmia, it was offset by an increase in the rate of death from nonarrhythmic causes,” commented Stefan H. Hohnloser, M.D., professor of medicine, J.W. Goethe University (Frankfurt, Germany), and one of the principal investigators.