ICDs — implantable cardioverter defibrillators (search) — work wonders for people whose hearts don't pump properly and are at risk for dangerous heart rhythms. The devices sense when the heart's regular beating rhythm starts to flutter. They then give an electric shock that restores a normal heartbeat.
The devices clearly help people with serious heart disease. Doctors hoped they'd also be able to help people whose hearts are damaged by a recent heart attack, a susceptible period for these abnormal rhythms. But that doesn't seem to be the case, report Stefan H. Hohnloser, MD, of J.W. Goethe University in Frankfurt, Germany, and colleagues in the Dec. 9 issue of The New England Journal of Medicine.
Hohnloser and colleagues implanted ICDs in 332 patients who'd had a heart attack in the last six to 40 days. They compared them with 342 recent heart attack patients who didn't get the implanted devices. All of the patients had serious heart damage resulting in significantly reduced ability to pump blood. On average, patients enrolled in the study only 18 days after having a heart attack.
As hoped, ICDs cut abnormal heart rhythm-related deaths by 58 percent. But they increased the risk of death from other causes — mostly heart failure — by 75 percent.
"The main finding of [this study is] that patients who have recently had a [heart attack] do not benefit from an ICD," Hohnloser and colleagues write. "The most likely explanation is that the patients 'saved' from [an abnormal heart rhythm]-related death by ICD therapy are also at high risk from other cardiac causes."
In an editorial accompanying the Hohnloser study, Anne M. Gillis, MD, notes that ICDs are "not for everybody." Gillis, a noted heart researcher, is medical scientist for Canada's Alberta Heritage Foundation for Medical Research.
Gillis notes that ICDs implanted soon after a serious heart attack "may simply convert what would have been a sudden death to a death from [heart pumping] failure, without an effect on survival."
SOURCES: Hohnloser, S.H.The New England Journal of Medicine, Dec. 9, 2004; vol 351: pp 2481-2488. Gillis, A.M. The New England Journal of Medicine, Dec. 9, 2004; vol 351: pp 2540-2542. Jauhar, S. The New England Journal of Medicine, Dec. 9, 2004; vol 351: pp 2542-2544.