Doctors have made great strides in treating acute heart attacks, yet sudden death from cardiac arrest fells many survivors months or even years after they're discharged from hospitals.
For years standard medical treatment to thwart these delayed killers has been various drugs to control patients' irregular, overly fast heartbeat. More recently, implantable defibrillators, tiny pacemakerlike devices that shock a wayward heart back into proper rhythm, have offered cardiologists a powerful treatment option.
Doctors, however, have wondered whether drugs or these devices offer their high-risk patients the best prognoses.
A recently published study, 10 years in the making, gives the nod to implantable defibrillators. The results, which appeared last month in the influential New England Journal of Medicine, are likely to boost hospital purchases of defibrillators, at a cost upward of $20,000 each. The study may also increase the number of patients cardiologists refer to hospital electrophysiology laboratories for testing. The results of those tests help predict which patients are most at risk and, therefore, the most likely to benefit from treatment.
A cardiologist at Rhode Island Hospital, Providence, led the study, which spanned 85 hospitals and clinics in the U.S. and Canada. The National Institutes of Health and nine manufacturers of drugs and medical devices funded the research, launched in 1989.
The participating doctors focused on patients at risk for sudden death from heart attack. They had a history of coronary artery disease, significantly reduced heart pumping capacity and intermittent bouts of rapid heartbeat. About 2,200 patients first had their hearts tested in hospital electrophysiology labs. Special wire catheters were used to electrically stimulate their hearts and trigger tachyarrhythmia-fast, irregular heartbeat. This condition is a harbinger of sudden death from heart attack and the study was originally conceived as a way to assess the value of electrophysiology testing in identifying high-risk patients. Nearly 800 patients experienced tachyarrhythmia at testing. Almost all these patients agreed to be randomly assigned to receive either no special treatment or therapy with drugs or an implantable defibrillator. In the treatment group, patients were equally divided between those who took drugs and those who got the implants.
The difference in their outcomes was striking.
The five-year rate of a heart attack or death from arrhythmia in patients with defibrillators was four times lower than in patients who received only drugs, or 9%, compared with 37%. Further, at five years, the overall death rate in patients who received defibrillators was one in four, or 24%, compared with more than half, or 55%, for patients who did not.
"It's not a surprise to me," says Rick Wise, medical technology analyst at Bear, Stearns & Co., who expects the results will nonetheless strengthen clinical support for the devices. "It's another piece of the mosaic that says to doctors and patients alike that they really have to consider even prophylactic use of (implantable defibrillators) in certain patient populations."