The annual cost to the government would triple from just over $1 billion to more than $3 billion in five years if it decides to pay for more older and disabled Americans to get the device, according to Minneapolis-based Medtronic Inc., one of three companies that make most defibrillators in the United States. Guidant Corp. of Indianapolis and St. Jude Medical Inc. of St. Paul are the other manufacturers.
Private insurers also are closely watching Medicare because they often follow the government's lead in coverage decisions.
Currently, Medicare pays about $25,000 a person for defibrillators that are implanted in 40,000 patients who have congestive heart failure each year. Medicare is looking at expanding that number to cover people with less severe congestive heart failure.
Defibrillators are the size of a stopwatch and implanted under the skin. Wires attach the device to the heart. The device senses an irregularly beating heart and shocks it back into proper rhythm.
Vice President Dick Cheney had a defibrillator implanted in 2001.
Paul Neill, 63, of Gaithersburg, Md., described the "huge kick from within" that has three times saved him from sudden cardiac arrest in the two years since he had the device installed. "It makes you realize you've just walked past death's door," Neill said at a news conference arranged by Medtronic.
Dr. Sean Tunis, Medicare's chief medical officer, said Wednesday he will meet this week with scientists who conducted the study to discuss its results in detail.
"We have to tease through what is spin and what's reality," Tunnis said. "Only after we feel we have a clear and precise understanding of the science will we explore policy issues," including the cost.
But Tunis said that if defibrillators cost only a few hundred dollars each, "it wouldn't be as critical to tease apart the data in exquisite detail."
About 450,000 people die in the United States each year from sudden cardiac arrest, where the heart stops beating without warning.
A Medicare advisory committee recommended a year ago that the government widen coverage. But the Centers for Medicare and Medicaid Services decided on a modest expansion, saying it would await the results of the new study.
Earlier trials showed a benefit in the severest cases of heart disease, but the new one extended that to more moderate disease, a category that includes between 1 million and 2 million Americans.
After almost four years of follow-up, there was a 23 percent reduction in death in those getting defibrillators. The study, conducted on 2,521 patients, was directed by Dr. Gust Bardy of the University of Washington and financed by the National Institutes of Health.
While expensive, defibrillators are more effective than drugs used to stave off sudden cardiac arrest, the study said.
Dr. Bruce Wilkoff, director of cardiac pacing at the Cleveland Clinic, said Medicare has been slow to make decisions about defibrillators. Tunis said a decision should come within nine months.
Until then, Dr. Marc Silver, a Raleigh, N.C., cardiologist, said he will have to tell Medicare patients that they are good candidates for defibrillators, but can get them only if they have the money.
"Most of our patients come from eastern North Carolina. It's not Beverly Hills," he said. "People aren't walking around with $30,000."
By Mark Sherman