Implanting defibrillators in patients just weeks after a heart attack does not improve their chances of survival, according to an international study. The researchers suggested instead that patients wait several months before having one of the devices inserted in the chest.
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The findings could have big implications for Medicare, which is about to expand coverage for the $25,000 devices to many more people.
Implanted defibrillators, such as the one Vice President Dick Cheney has, shock the heart back into a normal rhythm when it starts beating irregularly. Research has shown these devices save lives, but those studies were done almost exclusively on patients six months to several years after their heart attack.
The new study found that defibrillators offer little benefit in the early days after a heart attack, when patients with damaged and weakened heart muscle are most likely to die. In the study, reported in Thursday's New England Journal of Medicine, lives saved among patients who suffered abnormal rhythms were basically canceled out by deaths from heart problems unrelated to rhythm.
For doctors, this finding will complicate deciding exactly when to install the devices, and in which patients.
"We recommend that you wait at least six months after the heart attack," said the lead researcher, Dr. Stefan Hohnloser, professor of medicine and cardiology at J.W. Goethe University in Frankfurt, Germany.
The study involved patients who suffered a muscle-damaging heart attack just 6 to 40 days earlier, a group at high risk of death from another heart attack or gradual heart failure, or from abnormal rhythms.
In the United States, doctors usually wait at least one to three months after a patient's heart attack before implanting a defibrillator, said American Heart Association spokesman Dr. Kenneth Ellenbogen, a professor at Medical College of Virginia.
Currently, Medicare covers implantation of a defibrillator as little as a month after a heart attack. The federal health program for the elderly is expected to adopt a controversial plan by the end of the month to pay for the devices for many more patients, including people who have not had a heart attack but whose hearts are so damaged they cannot pump enough blood.
"The study provides a lot of important information (on timing of implantation), and we'll definitely be looking at it carefully as we make our final determination," said Dr. Sean Tunis, chief medical officer at the Center for Medicare and Medicaid Services.
Medicare spends about $1.5 billion a year for about 50,000 defibrillators. Various estimates, Tunis said, show those figures rising by 2007 to 150,000 to 200,000 defibrillator implants per year, costing $4 billion or more. In a measure of how much money is at stake, Johnson & Johnson is in talks to buy Guidant Corp., one of the top defibrillator makers, for more than $24 billion.
The 676-patient study was funded by St. Jude Medical of St. Paul, Minn., a defibrillator manufacturer for which Hohnloser serves as a consultant.
Half the patients had defibrillators implanted and half got standard medical treatment, including aspirin, medicines called ACE inhibitors and beta blockers to hold down blood pressure, and cholesterol-lowering drugs.
Of the 120 patients who died within an average follow-up of 2 1/2 years, 62 received defibrillators and 58 got standard treatment. The defibrillators reduced deaths from abnormal heart rhythm by about 60 percent, compared with the standard-treatment group. However, nearly twice as many defibrillator patients died of a heart attack or other nonrhythm causes.
Doctors said it is not entirely clear why more defibrillator patients died, but they do not believe the devices themselves harmed patients. Instead, they said patients in the comparison group may have received more aggressive drug treatment, and more of them had bypass surgery or artery-clearing angioplasty than the defibrillator group.
Also, doctors said that the defibrillators may have temporarily saved patients from a sudden death from a dangerous heart rhythm, only to have the underlying damage to the heart's pumping ability kill them later.
The findings, along with results of other studies, show that implanting defibrillators after a heart attack saves patients only after the short-term risk of heart failure or another heart attack has passed, said Dr. Marc Klapholz, chief of cardiology at University of Medicine and Dentistry of New Jersey in Newark.
Dr. Mina Chung, a cardiologist at the Cleveland Clinic, predicted the study will make doctors re-evaluate whether their patients should get a defibrillator soon after a heart attack.
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