MONDAY, June 12, 2006 (HealthDay News) -- People who've had a heart attack and receive an implanted defibrillator may be at increased risk of heart failure that often ends in death, a new study found.
"What we do is increase the quantity of life, but maybe the quality of life is not so good," said study lead author Dr. Ilan Goldenberg, a research assistant professor at the University of Rochester Medical Center, in New York.
Heart failure is the progressive loss of the heart's ability to pump blood. The study included 1,232 people who had had heart attacks and were given either the usual medical care, or that care plus an implanted defibrillator, which delivers a shock when needed to keep the heart beating regularly.
Two different kinds of defibrillators were used in the study -- one that delivered the shock to one chamber of the heart, and one that shocked both chambers. Overall, the survival benefit compared to people who got standard care was 42 percent for the single-chamber defibrillator recipients, and 51 percent for those with a double-chamber device.
But defibrillator recipients were 39 percent more likely to have a first hospitalization for heart failure and 58 percent more likely to have several such hospitalizations during an average follow-up period of 20 months, compared to patients who did not receive a defibrillator.
The lesson for physicians from the study is that "they should pay more attention to preventing heart failure" in heart attack patients, Goldenberg said.
The findings appear in the June 13 issue of the journal Circulation.
The study results were predictable, said Dr. Kenneth A. Ellenbogen, professor of medicine at the Medical College of Virginia, and a spokesman for the American Heart Association.
"Most people who are old and have heart disease die either from cardiac arrest or congestive heart failure," Ellenbogen said. "If you make sure they do not die of cardiac arrest by implanting a defibrillator, they can die either from heart failure or cancer. Heart failure is more probable."
Ellenbogen said the lesson from the study is that doctors "must very aggressively treat these patients to prevent development of heart failure." Drug such as ACE inhibitors, beta blockers and cholesterol-lowering statins "are essential and critical to prevent patients from heart failure," he said.
And for patients with a defibrillator, they should realize the device is effective against only one heart problem, cardiac arrest, Ellenbogen said. Other risk factors -- such as arteriosclerosis, blockage of the arteries -- are just as important, he said.
"Don't think that because you got a defibrillator, you can go out and have a Big Mac and not exercise," he said. "It is important to address every aspect of heart disease."
The defibrillator study is continuing, Goldenberg noted, testing whether two-chamber devices are more effective than one-chamber devices at preventing heart failure and death. Results are expected in one to two years, he said.
Favorable results for the two-chamber devices could pose economic concerns, because they are 10 percent to 20 percent more expensive than one-chamber defibrillators, Goldenberg said.
To learn more about defibrillators, visit the American Heart Association.